Make sure the oil is mixed right, people think adding oil helps but it thickens the fuel and effectively leans out the fuel mixture. We used to use that trick riding dirt bikes into the mountains and not having to play with the jets. If it is lean at part throttle raise the needle by lowering the clip one notch. Use a mikuni tuning guide to see what circuits are at play, the main jet does not come into the picture until about 3/4's throttle, 1/4 to 3/4 is on the needle jet.
Put a little oil on some sheet metal, just roof tin scraps oil inbetween top and bottom sheets, tires on dry tin, (so the tires can "squish" out) roll the mains onto it, put your body weight ( as sandbags) in the cockpit., THEN check the gear. After plumbing bob down from the prop bub to the ground, (be on level ground) same with the center rear, snap a chalkline, and using a 4 to 6 ' straightedge hold it against the tires/wheels, and see how it jives to your chalk lines.
Jonas, when you're hand-propping an engine and it doesn't start, PLEASE wait until the prop has completely stopped moving before you reach out to grab it again, and turn off the ignition switch if you're going to reposition the prop between swings (second person helping if you're standing in front). It can cough and pop over one more time, and it'll make a real mess of your hand if it does.
Kick back firing is highly unlikely with CDI. They need to turn 300 rpm at the crankshaft just to charge up the Capacitor and make the trigger coil fire the plugs before it'll ever start. So there is no way it will fire turning or moving slow. It doesn't work at all like a magneto. Sometimes those things would fire if you moved anything or looked at them sideways. Old style points, maybe but again unlikely. There were several 447s that ran with us years ago in our UL club. Most never had many problems. One did have a crank bearing disintegrate. Found a spot to land and didn't bend anything. It's all about setup. Prop pitch is critical. Warmed up static rpm with proper jetting should be between 6200 -6400. EGT should be between 950 (climb) - 1150 (cruise). You are looking for 6300-6350 in a hard climb out with Cht around 950-1050 with Cht climbing. Cruise will show the higher egt. Keep it at or below 1200. My preference is 1050-1150. I've never fouled a plug and I'd run them for 75 to 125 hours or more. All very safe ranges. When you get those temps figured out, it'll be time to check the plug color before you start changing things again. Also get an airfilter. The one you were using can be jetted to accept that filter. You need it for nothing else but to stop the fuel/air/oil from being blown away out the carb between strokes. You'll probably never have to oil the filter after the initial oiling because of this reason. I flew a Firestar with a 447. Great little engine. Took it on a 700 mile cross country to SNF in my younger crazy days. It never did give men any problems once setup properly. I have much more to say but have said enough at point. I'll keep watching and following. BTW I've got around 3500 hours or more in front and behind the Rotax. Good engine but you have to take special care of them or they'll put you in the weeds.
@@michaelhighsmith6692 I was looking at the keys on the dash of a rental when I pulled the prop thru for a compression check (something I added after losing a cylinder a few days before). The engine burst to life for a few seconds while I was leaning forward and off balance. The mixture was set to idle cut-off but it obviously had a bit of fuel in the pipes, plus the key was pulled out of the ignition switch in the right mag position. My face was about 6 inches from the prop disc, so it was a loooong few seconds.
This air bike is the plane I want. After flying a hang glider for 15 years and lessons in a Cessna years ago, this is the perfect wilderness, long distance flyer. I've also seen this model made for tandem 2 seater. A great ultra light. Keep your tail wheel between your main wheel track to avoid ground loop until you slow down. Always watch airspeed indicator. Always stabilize your approaches. Great video!!!
Hi Jonas & Silvija, I'm not a pilot been around flying a little bit. Love your channel! I am an old man.. I want to see you be an old man too. Put the correct air filter on the engine. Make sure you have the correct mixture of oil and fuel! If anything be a little bit heavy on the 2-cycle oil. I don't know how many jets your carb has. Look at your chart or see what the standard main jet is from the factory or go 1 size larger on the main fuel jet. Put the snap ring back to the factory setting. All that does is open your ventura quicker which dumps a lot air in very quickly... this is good if you are building a drag bike. Tie that plane up safe and sound. When you get your best throttle response and your highest rpm turn the air back a little to slow up the motor and let the fuel cool the engine you must have enough fuel flowing into the cylinders to cool the engine. Go talk to an older chain saw or weed eater mechanic that works on 2 cycles they will tell you if you are to lean you will burn the engine up. Fuel equals cool motor. Hope this helps. Listen to your lovely wife and be SAFE! Dannooo out!
Great Video! You should practice take-offs and landings on a grass strip. Grass is much more forgiving. EGT too hot = running too lean. Move the E-clip one notch lower in the needle to allow for more fuel. I love the Rotax 2-strokes!!! They sing when tuned right.
High EGT could be slight lean condition from not running any filter at all... so essentially reverse of original issue. Also kind of goes against my "mechanical sympathy" sensors running without a filter. I'd slap a big, nice breathing filter on and maybe a primer bulb to make starting a little easier and then tune jets and needles from there.
Nah you wanna adjust your prop. Only tune the carb by idle drop test using the mixture screw. Don't changes jets or needle unless its incorrect for your elevation.
That was exactly what I was thinking. Plus the airflow right there might not be ideal for the engine. What I would do is fabricate a flexible tube to come off of that carb into an airbox with a simple foam filter placed in front of and below the exhaust if possible. Honestly I would probably make it out of an old vacuum tube and hose and a plastic juice bottle for the airbox, use my solder iron to burn a hole in the side of the juice bottle just the right size for a standard filter, gorrilla tape that sucker onto the new “airbox” and use the mouth hole to route the vacuum hose into, which may also need “heat treated” to stretch the plastic. (you should see how awesome this idea is in my head)
Yup she's lean at 1200° now. Don't know about the prop pitch as some have said but could be. A lot of good information on here and some that don't have a clue 😆
@@429thunderjet2 Well, he said he had said he was running a rich jet, but the jet he kept changing, is just the idle jet right? changing the clip on the needle jet actually effects the high end right? Well, I guess they relate, I have a rotax 800 in my snowmobile, but it has this “dpm” system or something, it is 2 stroke but designed for the mountains and designed to operate between sea level and 10k ft without any adjustments. So you don’t have to adjust anything, but you do have to watch for cracks in the rubber manifold between carb and intake, because it will start sucking air and run lean and melt your piston / pistons. Ask me how I know.
When I raced snowmobiles in the '90s we always said maximum horsepower was at 1250F and the crankshaft got aluminum plated (by the melted pistons) at 1251. I went 106mph at 5700 feet one time on a radar run with the EGTs right on 1250. Risky but totally worth it!
Congrats, Jonas! I enjoy watching you "wrench" on the plane just as much as watching you fly it, so show us all the little tweaks you are making to the prop and so on!
Excellent listening to all the advice. Sometimes info is bad not intentional just not standing there to analyze the problem. But good on you for working through taking everything into consideration.
Agree with comments about old seals causing possible lean condition. If you have good seals and a filter and EGT remains high, you can re-pitch the prop up by a degree or two. Egt will go down and cht will increase. So long as your static rpm’s are good and cht is still in spec that may help solve the problem. And, running without a filter is BAD. Any debris makes it into the cylinder you will score the walls and pooch the engine.
Just had a chance to meet this young man today. He is passionate about sport flying and I encourage everyone to support his flying addiction. This is true flying just for the love of it, even in the backwaters of eastern Idaho. Take care and safe travels.
You’re on the right track when you said you should add pitch to the prop to get your egt’s down. Rotax 2 strokes need to be loaded to run at proper temps. Many guys improperly reduce power shortly after take off , which is the worst thing you can do with the 2 stroke. Keep in mind 3 out of 4 Rotax pilots have had an engine quit and 90 % of those are improper operation. Read the manual and do what it says. Good luck.
Lots of respect. Wearing personal safety gear, good shoulder harness set-up, respecting bad wind conditions and immediately aborting when the engine is not running correctly. A few You Tube Ultralight “pilots” who’ve posted videos recently should take note.
If you haven't, be sure to check all the air seals. A small leak will create that hard start and cause high EGT. Crank seals drying out are super common and make tiny leaks that can melt an engine down while everything else seems fine.
@@AnonyMous-jf4lc it sure as h€ll does. It's a slide valve carb, so if it's a Mikuni, Keihin, Bing style there is no choke plate it's a plunger valve and it quits pulling fuel through the choke/enrichment tube when you open the throttle because the vacuum pulling fuel through it drops.
@@429thunderjet2 it’s a venturi. The mix is still enriched, there’s just more everything. Same way it still pulls fuel from the bowl when the throttle is open. If it was full vacuum, it would instantly flood and maybe even hydro lock. Physics are cool.
Hi Jonas. I just spoke with you through my RV-8 friend George. How cool! Love following you in your adventures! Good luck with the ultralight. That jet needle rubber o-ring may not be on the 447. you may want to check with an expert. Safe flying! Great talking to you.
Jonas,love your videos man. I’ve flown 2 strokes for 5 years. And grew up with them in my sleds. Tie the Airbike off and do a full throttle static run. Your RPM’s should be no more than 6250(that’s always been my goal number to see and works very well). It’ll unload inflight to around 6500-6600. That will make both your EGT,and CHT happy. And if your jetting is where they should be,it’ll work good for you. As for no air filter,that’s a no no. Get a bigger air filter. The one you had was definitely small,despite it being called out for in the Rotax book. Jetting,and prop pitch are a married couple. They both affect eachother and work together for good engine healthy and happy temps. Full throttle in level flight,you will get an over hot EGT. It’s due to not being loaded(like in a climb). Hope this helps. Be safe and keep the videos coming. Terry from Michigan.
I think you need to add a couple degrees to your prop … I had the same issue for some time … turned out to be that the prop needed to be adjusted to a bit more of a bite… It immediately fixed the EGT problem
It is nice to see a problem solved and some reward for your labor...... I am sure will get it dialed in and have some more fun. Be safe, thanks for the vid.
Hi Jonas, to correctly tune the engine the air filter must be fitted. I’ve used that type you have in the past without issues. I think you had a combination of little errors causing your problems before. Now with the needle clip in the correct position in slide, I think you will be able to use the filter you have. 1150 - 1200 on full power is ok. That is on the main jet and needle clip positions. Raising the needle will enrichen the mixture. So it’s safe to do that after this run was on the high side. Check EGT at cruise 1050-1150. This is achieved by changing the needle jet. Which is kept in place via the emulsion tube.
@ WOT your Egt s should be cooler then at cruz. If your jetted correctly to alt & temp. Check engine seals, with pressure testing case. No max then 6psi with no more then 1lb leak in 2 mins.
Jonas: 100LL just went up to $10 per gallon in VA. This might be the only thing we can afford to fly for awhile. Congratulations on the progress. You will have it dialed in soon. I want to see that ear to ear smile from the video on your first Airbike
I had a Rotax 447 on a home built many years ago. It did not have a primer - I found that if you plugged one carb vent line with your thumb and blew into the other that would draw fuel into the carb for easier starts.
Oh interesting, you are pressurizing the float bowl pushing fuel up the main jet/emulsion tube & pilot jet into the throat of the carb. Never thought of that.
Watch 2 things on a Rotax. Paper or foam air filters and paper fuel filter. Both have put me down. Only use stainless steel metal screens for both. Paper or foam clogs over time from the oil in the mixture.
This reminded me of an experiment a friend of mine did with his dirt bike many years ago. He thought the air filter he bought was not giving enough air flow, so he stretched a couple of layers of nylon stockings over the air intake and held it on with a rubber band ( do not actually run any engine this way for any length of time, you'll melt the nylon ). The nylon kept the dust and dirt out long enough for him to run it for about a minute and a half. Proving he was right before he spent the money for another air filter.
Congrats bro glad it flew try finding a different air filter or richen it up cause I am pretty sure you leaned it out with the air filter off you might be able to bring the egt down by adding more prop but I think you have better luck with a richer jet
You want 6500 at full throttle. Cool air means low density altitude, and lots of oxygen. Lower the clip to raise the needle. More fuel will give you lower EGT's. That 6500 RPM is a must. The old CPS (California Power Sports) catalog always had the best explanation of the ROTAX motor and BING carburetors.
The cooling shroud needs to cover the heads to cool properly, the stock fan system will fix all the engine temperature problems. The EGT also goes up when the crank seals leak leaning out the mixture, That engine sat long enough to make that a concern even if it wasn't run.
1200 is definitely high but not extreme for a 2-stroke air-cooled sledge-engine. It will reach high temps fast during max load! Two-strokes uses resonance (back-pressure) in the pipe… Lack of filter might making it a bit in the lean side (thus warmer), but look at the plugs first of all. They will tell you more than any EGT-sensor. Well done so far getting it up in the air and all..!
Nice work Jonas! EGT is a result of fuel mixture and will not change with airflow as you suggested in this video. CHT however will change with airflow. I would recommend putting a lager filter on ASAP, this will look after your engine and slightly increase the mixture by restricting the airflow a little. Have a little tweak of your fuel mixture and see how you go, and have fun! Safe flying!
That is a big motorcycle carburetor . If you run pump gas with ethanol you might need to go bigger on the main jet . If you were not running full throttle try running the needle up 1 notch and take that short run again . Don’t put more pitch on the prop until you get the mixture figured out . If 2 stroke engines are run lean they can burn pistons . If you go too rich you can’t hurt anything .
Idle jet: idle to 1/4 throttle Needle jet clip: 1/4 throttle to about 3/4 throttle Full throttle: main jet I would definitely recommend doing a plug chop. Warm the engine up then put a brand new plug in. Start and immediately go full throttle for a high speed taxi then kill the engine. Check the plug for color. You want a nice darker grey color. Black is too rich, white is too lean.
Be careful running it lean… two-stroke Rotax engines need the oil in the fuel for lubrication. In addition, make sure she’s fully warmed up before revving it up. You can easily get a cold seizure if not.
I love the Airbike! There are some confusing comments. I'm uncertain what a 4-stroking 2-stroke is. I doubt your high egt temps are from a rich mixture "flaming" the egt probe. I agree the air filter might be over oiled, it looks large enough. When reading spark plugs, look at the ground electrode (attached to the spark plug threads). There will be carbon on it, if you look closely you will see a "line" where the color and or texture changes. You want that line to be in the middle of the turn (bend) from the center of the plug to the thread area (if that makes any sense?). If the "line" is towards the center it's rich, towards the threads is lean. Reading "piston wash" is the proper way to tune a 2 stroke! Keep up the great work!
Heya! just one of the guys that went through the same headache with a dirtbike and an “upgraded air filter” that all my friends said couldn’t be the issue 😂.
Know little about planes but lots about 2 stroke bikes. The big no no' s then are never go lean and set the timing accurately and also the correct plug grade. Defo put an air filter on it and one with lots if surface area. You will have to retune with the filter on as it will change the mixture.
Changing the prop pitch will change your EGT’s, less pitch =‘s lower EGT’s and higher CHT’s. More pitch =‘s higher EGT’s and lower CHT’s Also flying without the air filter changes your temps, that could be another reason you are getting a high EGT temp. Without the filter your getting too much air and leaning it out. Love the channel, keep up the good work! -Tabor
I just change the clip position depending on season. I target 1100 max on the EGT. My EGT has been calibrated to a known reference source and is cold junction compensated so it’s accurate. Seems to work, been doing this for about eight years. Runs perfect.
I have a small 2 stroke that will not run properly with the factory velocity stack installed. No filter, just a small 1 inch tall Bakelite stack! It's quite bizarre. Some motors have a strange personality! Sorry?..engines! Good lock Jonas, watch the ground loop. You don't have a big tail area with open fuselage aft!
Check your static rpm (on the ground rpm)and make sure the rpm is 3-400 less than max rpm. If you don’t have enough pitch in the prop it will run hot. I had a quicksilver mx that was running hot until I increased the pitch.
Try increasing prop pitch. You previously stated that to lower egt to lower throttle and pitch down. Actually climbing will lower the egt. That’s equivalent to increasing prop pitch and an indicator to increase pitch. Also, check your video, it looks like the right wheel wants to go in on landing.
High EGT can also be related to the Rich Mixture. Unburnt fuel ends up burning on the exhaust pipe and not inside the cylinder. This is the reason that Using EGT is not recommended for leaning out an engine.
I didn't get a chance to read all the comments so I may be repeating what other's have already said but here you go anyway. Full power static (tied to a tree) RPM should be around 6200. Adjust the prop pitch to achieve this. If you need to add more pitch to your current set-up, that will probably cure your EGT problem. High EGTs come from an unloaded prop on a 2-stroke. Keep it loaded up with pitch and it'll keep the EGTs down. Also, don't trust the gauge 100%. Read the sparkplugs to be sure that they're a nice dark tan colour. Other than that, congrats on getting airborne! What a thrill! Edit: They don't like starting when they're hot. I find that if you open the throttle to about a quarter with no choke, they start easier when hot.
More pitch will bring the EGT down. On my 582 Rotax I jet for about 1000 deg F EGT in level flight and I have a HACman mixture control to lean from there. I have found that 1000 F EGT in level flight works well with the HACman Mixture. Jetted this way you can make shallow descents which will raise EGT, but you have a buffer. Otherwise if you EGT is too close to 1200 you will have to "chop and drop". It also doesn't foul plugs at the 1000 F EGT. HACman mixture is very simple and you can either buy one or DIY it. It allows you to Run richer (safer), but have the ability to lean a bit. Also saves having to rejet every time the ambient temperature decides to swing a bit.
Awesome you got to fly it.. Summer is coming and you can fly to your hearts content. I noticed you weren’t using a air filter, that could cause you ETG to heat up some. If you put a new big old KT filter on that might cure your heating. Enjoy your toy!!
Wait till the winds are calm. Start earlier in the day.
Juan’s in the house!!!!
...or late in the day. Take it from an old ultralighter when you can throw a frisbee down the centerline and it doesnt get offline! 😁
You finally got it Wright,Brother! 👍😂
Make sure the oil is mixed right, people think adding oil helps but it thickens the fuel and effectively leans out the fuel mixture. We used to use that trick riding dirt bikes into the mountains and not having to play with the jets. If it is lean at part throttle raise the needle by lowering the clip one notch. Use a mikuni tuning guide to see what circuits are at play, the main jet does not come into the picture until about 3/4's throttle, 1/4 to 3/4 is on the needle jet.
Put a little oil on some sheet metal, just roof tin scraps oil inbetween top and bottom sheets, tires on dry tin, (so the tires can "squish" out) roll the mains onto it, put your body weight ( as sandbags) in the cockpit., THEN check the gear. After plumbing bob down from the prop bub to the ground, (be on level ground) same with the center rear, snap a chalkline, and using a 4 to 6 ' straightedge hold it against the tires/wheels, and see how it jives to your chalk lines.
Jonas, when you're hand-propping an engine and it doesn't start, PLEASE wait until the prop has completely stopped moving before you reach out to grab it again, and turn off the ignition switch if you're going to reposition the prop between swings (second person helping if you're standing in front). It can cough and pop over one more time, and it'll make a real mess of your hand if it does.
Kick back firing is highly unlikely with CDI. They need to turn 300 rpm at the crankshaft just to charge up the Capacitor and make the trigger coil fire the plugs before it'll ever start. So there is no way it will fire turning or moving slow. It doesn't work at all like a magneto. Sometimes those things would fire if you moved anything or looked at them sideways. Old style points, maybe but again unlikely. There were several 447s that ran with us years ago in our UL club. Most never had many problems. One did have a crank bearing disintegrate. Found a spot to land and didn't bend anything. It's all about setup. Prop pitch is critical. Warmed up static rpm with proper jetting should be between 6200 -6400. EGT should be between 950 (climb) - 1150 (cruise). You are looking for 6300-6350 in a hard climb out with Cht around 950-1050 with Cht climbing. Cruise will show the higher egt. Keep it at or below 1200. My preference is 1050-1150. I've never fouled a plug and I'd run them for 75 to 125 hours or more. All very safe ranges. When you get those temps figured out, it'll be time to check the plug color before you start changing things again. Also get an airfilter. The one you were using can be jetted to accept that filter. You need it for nothing else but to stop the fuel/air/oil from being blown away out the carb between strokes. You'll probably never have to oil the filter after the initial oiling because of this reason. I flew a Firestar with a 447. Great little engine. Took it on a 700 mile cross country to SNF in my younger crazy days. It never did give men any problems once setup properly. I have much more to say but have said enough at point. I'll keep watching and following. BTW I've got around 3500 hours or more in front and behind the Rotax. Good engine but you have to take special care of them or they'll put you in the weeds.
@@michaelhighsmith6692 I was looking at the keys on the dash of a rental when I pulled the prop thru for a compression check (something I added after losing a cylinder a few days before). The engine burst to life for a few seconds while I was leaning forward and off balance. The mixture was set to idle cut-off but it obviously had a bit of fuel in the pipes, plus the key was pulled out of the ignition switch in the right mag position. My face was about 6 inches from the prop disc, so it was a loooong few seconds.
This air bike is the plane I want. After flying a hang glider for 15 years and lessons in a Cessna years ago, this is the perfect wilderness, long distance flyer. I've also seen this model made for tandem 2 seater. A great ultra light. Keep your tail wheel between your main wheel track to avoid ground loop until you slow down. Always watch airspeed indicator. Always stabilize your approaches.
Great video!!!
Congratulations, you flew it !!!
Hi Jonas & Silvija, I'm not a pilot been around flying a little bit. Love your channel! I am an old man.. I want to see you be an old man too. Put the correct air filter on the engine. Make sure you have the correct mixture of oil and fuel! If anything be a little bit heavy on the 2-cycle oil. I don't know how many jets your carb has. Look at your chart or see what the standard main jet is from the factory or go 1 size larger on the main fuel jet. Put the snap ring back to the factory setting. All that does is open your ventura quicker which dumps a lot air in very quickly... this is good if you are building a drag bike. Tie that plane up safe and sound. When you get your best throttle response and your highest rpm turn the air back a little to slow up the motor and let the fuel cool the engine you must have enough fuel flowing into the cylinders to cool the engine. Go talk to an older chain saw or weed eater mechanic that works on 2 cycles they will tell you if you are to lean you will burn the engine up. Fuel equals cool motor. Hope this helps. Listen to your lovely wife and be SAFE! Dannooo out!
Great Video! You should practice take-offs and landings on a grass strip. Grass is much more forgiving. EGT too hot = running too lean. Move the E-clip one notch lower in the needle to allow for more fuel. I love the Rotax 2-strokes!!! They sing when tuned right.
Well done, I hope your well insured
It's good to see you having fun.
High EGT could be slight lean condition from not running any filter at all... so essentially reverse of original issue. Also kind of goes against my "mechanical sympathy" sensors running without a filter. I'd slap a big, nice breathing filter on and maybe a primer bulb to make starting a little easier and then tune jets and needles from there.
Nah you wanna adjust your prop. Only tune the carb by idle drop test using the mixture screw. Don't changes jets or needle unless its incorrect for your elevation.
That was exactly what I was thinking. Plus the airflow right there might not be ideal for the engine. What I would do is fabricate a flexible tube to come off of that carb into an airbox with a simple foam filter placed in front of and below the exhaust if possible. Honestly I would probably make it out of an old vacuum tube and hose and a plastic juice bottle for the airbox, use my solder iron to burn a hole in the side of the juice bottle just the right size for a standard filter, gorrilla tape that sucker onto the new “airbox” and use the mouth hole to route the vacuum hose into, which may also need “heat treated” to stretch the plastic. (you should see how awesome this idea is in my head)
Yup she's lean at 1200° now. Don't know about the prop pitch as some have said but could be. A lot of good information on here and some that don't have a clue 😆
@@429thunderjet2 Well, he said he had said he was running a rich jet, but the jet he kept changing, is just the idle jet right? changing the clip on the needle jet actually effects the high end right? Well, I guess they relate, I have a rotax 800 in my snowmobile, but it has this “dpm” system or something, it is 2 stroke but designed for the mountains and designed to operate between sea level and 10k ft without any adjustments. So you don’t have to adjust anything, but you do have to watch for cracks in the rubber manifold between carb and intake, because it will start sucking air and run lean and melt your piston / pistons. Ask me how I know.
@@nikhayes3396 midrange mostly, maybe a touch on wide open only.
Keep it up dude...have some fun!
When I raced snowmobiles in the '90s we always said maximum horsepower was at 1250F and the crankshaft got aluminum plated (by the melted pistons) at 1251. I went 106mph at 5700 feet one time on a radar run with the EGTs right on 1250. Risky but totally worth it!
The way this dude and his ol lady talks about country folks I really hope I bump into him sometime.
Congrats, Jonas! I enjoy watching you "wrench" on the plane just as much as watching you fly it, so show us all the little tweaks you are making to the prop and so on!
Amazing. Congrats
I'll be there on the 22nd of this month, I hope to see you flying it. Look out for the silver and blue Mooney
Excellent listening to all the advice. Sometimes info is bad not intentional just not standing there to analyze the problem. But good on you for working through taking everything into consideration.
Agree with comments about old seals causing possible lean condition. If you have good seals and a filter and EGT remains high, you can re-pitch the prop up by a degree or two. Egt will go down and cht will increase. So long as your static rpm’s are good and cht is still in spec that may help solve the problem. And, running without a filter is BAD. Any debris makes it into the cylinder you will score the walls and pooch the engine.
Just had a chance to meet this young man today. He is passionate about sport flying and I encourage everyone to support his flying addiction. This is true flying just for the love of it, even in the backwaters of eastern Idaho. Take care and safe travels.
You’re on the right track when you said you should add pitch to the prop to get your egt’s down. Rotax 2 strokes need to be loaded to run at proper temps. Many guys improperly reduce power shortly after take off , which is the worst thing you can do with the 2 stroke. Keep in mind 3 out of 4 Rotax pilots have had an engine quit and 90 % of those are improper operation. Read the manual and do what it says. Good luck.
Lots of respect. Wearing personal safety gear, good shoulder harness set-up, respecting bad wind conditions and immediately aborting when the engine is not running correctly. A few You Tube Ultralight “pilots” who’ve posted videos recently should take note.
If you haven't, be sure to check all the air seals. A small leak will create that hard start and cause high EGT. Crank seals drying out are super common and make tiny leaks that can melt an engine down while everything else seems fine.
I'm also thinking crank seal leak. I've had two 2 strokes with crank seal leaks with very similar symptoms. Fixed the seals and all fine.
Aaw it just needs choke! If you open the throttle it bypasses the choke mostly, so keep the throttle closed to start when the choke is on
@@429thunderjet2 I’m sure he knows how to choke it. Throttle doesn’t bypass the choke.
@@AnonyMous-jf4lc it sure as h€ll does. It's a slide valve carb, so if it's a Mikuni, Keihin, Bing style there is no choke plate it's a plunger valve and it quits pulling fuel through the choke/enrichment tube when you open the throttle because the vacuum pulling fuel through it drops.
@@429thunderjet2 it’s a venturi. The mix is still enriched, there’s just more everything. Same way it still pulls fuel from the bowl when the throttle is open. If it was full vacuum, it would instantly flood and maybe even hydro lock. Physics are cool.
This is awesome dude. I've been wanting a real 103 legal flyer for a while now. Thanks for sharing the journey.
Hi Jonas. I just spoke with you through my RV-8 friend George. How cool! Love following you in your adventures! Good luck with the ultralight. That jet needle rubber o-ring may not be on the 447. you may want to check with an expert. Safe flying! Great talking to you.
Good talking with you! Thanks for the heads up on the o ring.
Maybe one of these days we will visit your airport!
With my 447 I used to tie the tail down and pitch the prop for 6,000 RPM at full throttle. The 447 develops Max torque at 6000.
Jonas,love your videos man. I’ve flown 2 strokes for 5 years. And grew up with them in my sleds.
Tie the Airbike off and do a full throttle static run. Your RPM’s should be no more than 6250(that’s always been my goal number to see and works very well). It’ll unload inflight to around 6500-6600. That will make both your EGT,and CHT happy. And if your jetting is where they should be,it’ll work good for you. As for no air filter,that’s a no no. Get a bigger air filter. The one you had was definitely small,despite it being called out for in the Rotax book. Jetting,and prop pitch are a married couple. They both affect eachother and work together for good engine healthy and happy temps. Full throttle in level flight,you will get an over hot EGT. It’s due to not being loaded(like in a climb). Hope this helps. Be safe and keep the videos coming. Terry from Michigan.
how can i get a hold of you? I have some questions :)
I think you need to add a couple degrees to your prop … I had the same issue for some time … turned out to be that the prop needed to be adjusted to a bit more of a bite…
It immediately fixed the EGT problem
Fantastic video! You also showed that it may take some time to work out all the bugs but you can if you persevere.
It is nice to see a problem solved and some reward for your labor...... I am sure will get it dialed in and have some more fun. Be safe, thanks for the vid.
Hi Jonas, to correctly tune the engine the air filter must be fitted. I’ve used that type you have in the past without issues. I think you had a combination of little errors causing your problems before. Now with the needle clip in the correct position in slide, I think you will be able to use the filter you have. 1150 - 1200 on full power is ok. That is on the main jet and needle clip positions. Raising the needle will enrichen the mixture. So it’s safe to do that after this run was on the high side. Check EGT at cruise 1050-1150. This is achieved by changing the needle jet. Which is kept in place via the emulsion tube.
@ WOT your Egt s should be cooler then at cruz. If your jetted correctly to alt & temp. Check engine seals, with pressure testing case. No max then 6psi with no more then 1lb leak in 2 mins.
Write in English please.
@@rogerturner5504 Witch part are we struggling with?
@@darylbuckner5596 A witch is a lady dressed in black flying a broomstick. Stuff like that.
@@rogerturner5504 are you familiar with two strokes?
Yep looks super safe.
I would love to see some videos of you working on your haybine that you purchased.
Have a good time you’ll figure it out
Need a fuel primer hooked to the side of the carb if you don’t already have one starts better 👍
Jonas: 100LL just went up to $10 per gallon in VA. This might be the only thing we can afford to fly for awhile. Congratulations on the progress. You will have it dialed in soon. I want to see that ear to ear smile from the video on your first Airbike
Whoa ten bucks! $5.09 yesterday in the frozen tundra
Yes! Congrats 🍾 enjoy 😊
I had a Rotax 447 on a home built many years ago. It did not have a primer - I found that if you plugged one carb vent line with your thumb and blew into the other that would draw fuel into the carb for easier starts.
I’m going try this! I’ve been blowing in the tank.
Oh interesting, you are pressurizing the float bowl pushing fuel up the main jet/emulsion tube & pilot jet into the throat of the carb. Never thought of that.
Watch 2 things on a Rotax. Paper or foam air filters and paper fuel filter. Both have put me down. Only use stainless steel metal screens for both. Paper or foam clogs over time from the oil in the mixture.
Thanks for the tip!
This reminded me of an experiment a friend of mine did with his dirt bike many years ago. He thought the air filter he bought was not giving enough air flow, so he stretched a couple of layers of nylon stockings over the air intake and held it on with a rubber band ( do not actually run any engine this way for any length of time, you'll melt the nylon ). The nylon kept the dust and dirt out long enough for him to run it for about a minute and a half. Proving he was right before he spent the money for another air filter.
Excellent film footage and sound. Great commentary.
I could feel your anxiety. I got to had it to you, you have guts! Great Job. Thanks for the ride! Stay safe and God Bless!
This is the content that we all want to see right now
May I suggest a balistic parachute? I have three friends who would still be here if they had one.
That’s awesome!
Can't wait for the Capella repair series........................................... It's getting warmer now in the hanger.
Excellent Work!
Keep those nerves they are what keep you alive. Nice video glad to see it get up and go. Regards, Jim in NI UK
Sweet...really like the videos man keep em comin
Yay! Back to flying vids.
Omg you have flying fever! I have had this! It's an awesome feeling.. Just be careful man! Peace.. Thanks for all you do..
Congrats bro glad it flew try finding a different air filter or richen it up cause I am pretty sure you leaned it out with the air filter off you might be able to bring the egt down by adding more prop but I think you have better luck with a richer jet
I'm over here so excited!! I've always wanted to pilot somthing like that..! Im a faithful watcher!
Happy FOR YOU! Great Prop wash! Wishing you Lots of luck!
You want 6500 at full throttle. Cool air means low density altitude, and lots of oxygen. Lower the clip to raise the needle. More fuel will give you lower EGT's. That 6500 RPM is a must. The old CPS (California Power Sports) catalog always had the best explanation of the ROTAX motor and BING carburetors.
The cooling shroud needs to cover the heads to cool properly, the stock fan system will fix all the engine temperature problems. The EGT also goes up when the crank seals leak leaning out the mixture, That engine sat long enough to make that a concern even if it wasn't run.
A happy landing is a good landing. Your airplane thanks you, your fans thank and, most of all, Silvija thanks you.
Great video very educational and it’s good your putting safety first
Jonas I respect your decisions on safety first, one shot to do it right, nicely done my friend.😤👏👍😊
1200 is definitely high but not extreme for a 2-stroke air-cooled sledge-engine. It will reach high temps fast during max load!
Two-strokes uses resonance (back-pressure) in the pipe…
Lack of filter might making it a bit in the lean side (thus warmer), but look at the plugs first of all. They will tell you more than any EGT-sensor.
Well done so far getting it up in the air and all..!
Nice work Jonas! EGT is a result of fuel mixture and will not change with airflow as you suggested in this video. CHT however will change with airflow. I would recommend putting a lager filter on ASAP, this will look after your engine and slightly increase the mixture by restricting the airflow a little. Have a little tweak of your fuel mixture and see how you go, and have fun! Safe flying!
Good stuff. Hard work is paying off
Excellent as usual!!!
That is a big motorcycle carburetor . If you run pump gas with ethanol you might need to go bigger on the main jet . If you were not running full throttle try running the needle up 1 notch and take that short run again . Don’t put more pitch on the prop until you get the mixture figured out . If 2 stroke engines are run lean they can burn pistons . If you go too rich you can’t hurt anything .
Idle jet: idle to 1/4 throttle
Needle jet clip: 1/4 throttle to about 3/4 throttle
Full throttle: main jet
I would definitely recommend doing a plug chop. Warm the engine up then put a brand new plug in. Start and immediately go full throttle for a high speed taxi then kill the engine. Check the plug for color. You want a nice darker grey color. Black is too rich, white is too lean.
Be careful running it lean… two-stroke Rotax engines need the oil in the fuel for lubrication. In addition, make sure she’s fully warmed up before revving it up. You can easily get a cold seizure if not.
Use an oil like KLOTZ RACING RED castor bean oil and you can run it lean.
Well that's just rude.
@@glennllewellyn7369 Well, alrighty then,,,,.
@@johnslugger
Hahahahahahahaha!!!
One step at a time. Every flight with safe landing is a promise on more!
I love the Airbike! There are some confusing comments. I'm uncertain what a 4-stroking 2-stroke is. I doubt your high egt temps are from a rich mixture "flaming" the egt probe. I agree the air filter might be over oiled, it looks large enough. When reading spark plugs, look at the ground electrode (attached to the spark plug threads). There will be carbon on it, if you look closely you will see a "line" where the color and or texture changes. You want that line to be in the middle of the turn (bend) from the center of the plug to the thread area (if that makes any sense?). If the "line" is towards the center it's rich, towards the threads is lean. Reading "piston wash" is the proper way to tune a 2 stroke! Keep up the great work!
Heya! just one of the guys that went through the same headache with a dirtbike and an “upgraded air filter” that all my friends said couldn’t be the issue 😂.
It looks like your wheels are toed out. That will make it squirrelly on the ground. You need an air filter, just not that tiny one.
Yup! Plus an air filter will make it run richer Thus KEEPING THE MOTOR COOLER.
Know little about planes but lots about 2 stroke bikes. The big no no' s then are never go lean and set the timing accurately and also the correct plug grade. Defo put an air filter on it and one with lots if surface area. You will have to retune with the filter on as it will change the mixture.
It flew.. a brave test pilot.!!!
Changing the prop pitch will change your EGT’s, less pitch =‘s lower EGT’s and higher CHT’s.
More pitch =‘s higher EGT’s and lower CHT’s
Also flying without the air filter changes your temps, that could be another reason you are getting a high EGT temp.
Without the filter your getting too much air and leaning it out.
Love the channel, keep up the good work!
-Tabor
Sounds much better even on the startup...!
It'll happen... It's happening!
I just change the clip position depending on season. I target 1100 max on the EGT. My EGT has been calibrated to a known reference source and is cold junction compensated so it’s accurate. Seems to work, been doing this for about eight years. Runs perfect.
must be a little lean yet. raise needle one by lowering clip or go up 2 main jet sizes.
I like the Hipster 'overalls' shoulder harness on this machine.
Woo! Congrats and can't wait to see more pattern work
I have a small 2 stroke that will not run properly with the factory velocity stack installed. No filter, just a small 1 inch tall Bakelite stack! It's quite bizarre. Some motors have a strange personality! Sorry?..engines! Good lock Jonas, watch the ground loop. You don't have a big tail area with open fuselage aft!
Check your static rpm (on the ground rpm)and make sure the rpm is 3-400 less than max rpm. If you don’t have enough pitch in the prop it will run hot. I had a quicksilver mx that was running hot until I increased the pitch.
great! soon you will get the temp under control and should be able to fly longer! Congrats on the progress made so far!
Try increasing prop pitch. You previously stated that to lower egt to lower throttle and pitch down. Actually climbing will lower the egt. That’s equivalent to increasing prop pitch and an indicator to increase pitch. Also, check your video, it looks like the right wheel wants to go in on landing.
thanks Jonas, this whole process has been educational and fun to watch. Be safe!
you could get that vibe coompletely ready to repaint if you keep doing a tied down runup there. ;)
haha it does need a new paint job! The odometer is stuck at 299999 miles so not sure its worth it though.
congratulations 🎉
You two are AWESOME! Keep living life. I thought I wanted an airbike for years. moving towards a quicksilver now. Keep it up.
High EGT can also be related to the Rich Mixture. Unburnt fuel ends up burning on the exhaust pipe and not inside the cylinder. This is the reason that Using EGT is not recommended for leaning out an engine.
I’m so happy for you Jonas! Congrats on getting your wings back!!!! 🎉❤
I didn't get a chance to read all the comments so I may be repeating what other's have already said but here you go anyway.
Full power static (tied to a tree) RPM should be around 6200. Adjust the prop pitch to achieve this. If you need to add more pitch to your current set-up, that will probably cure your EGT problem. High EGTs come from an unloaded prop on a 2-stroke. Keep it loaded up with pitch and it'll keep the EGTs down. Also, don't trust the gauge 100%. Read the sparkplugs to be sure that they're a nice dark tan colour. Other than that, congrats on getting airborne! What a thrill!
Edit: They don't like starting when they're hot. I find that if you open the throttle to about a quarter with no choke, they start easier when hot.
Thank you for your input! I’ll try your tip next time starting it hot.
More pitch will bring the EGT down. On my 582 Rotax I jet for about 1000 deg F EGT in level flight and I have a HACman mixture control to lean from there. I have found that 1000 F EGT in level flight works well with the HACman Mixture. Jetted this way you can make shallow descents which will raise EGT, but you have a buffer. Otherwise if you EGT is too close to 1200 you will have to "chop and drop". It also doesn't foul plugs at the 1000 F EGT. HACman mixture is very simple and you can either buy one or DIY it. It allows you to Run richer (safer), but have the ability to lean a bit. Also saves having to rejet every time the ambient temperature decides to swing a bit.
Congrats on figuring out the air filter. Do things at your own pace, when it's right and when you are ready.
Awesome you got to fly it.. Summer is coming and you can fly to your hearts content. I noticed you weren’t using a air filter, that could cause you ETG to heat up some. If you put a new big old KT filter on that might cure your heating. Enjoy your toy!!
Dont leave ntake open like that, put at least Tatjanas stocking over it or something, you dont want dust in your engine.
haha I could try that 😄I have a larger air filter coming
High EGT is most likely lean mixture, or late ignition timing. Is there any posebilety to ajust the hight of the needle ??
yay.. glad that you got it going... and dont worry.. the snow will help with lowering the EGTs lol
Well its about time
glad the comment warriors helped!