Makes sense has enough compression to run cold but when it’s warm the valve stem expands with heat (getting longer) and hold the valves open to the point where it no longer has enough compression to run
thath could be the problem i'm a mecanic from italy ( sorry about the grammar) if the engien is getting warm the walves expend just a tini little bit but thath could be enof so that the engien has no compression and the outtake walfe gets hotter and longer than when the piston gows down to suck fule up and it can not create a good vacumme and no good compresion
An engine needs three things to run. Spark, fuel/air, and compression. Now you have a nice blue spark so that’s not the problem. Also because the engine didn’t run off the starting fluid there is nothing wrong with your fuel. If there was something wrong with the fuel the engine would have run off the staring fluid. So this leaves one thing, compression. It could be incorrectly adjusted valves or crack in the block but there is a compression leak or the just doesn’t have enough compression. I hope this helps
I mentioned this many videos ago - I have a feeling you dont read all the comments? You have the left float bowl on the right carb and the right bowl on the left carb - if you swap them the drain screws will FACE OUTWARDS, and you'll be able to get to them easier
Hey , i am a mechanical engineer from germany and therefore know something about engines. Valve clearence is needed to compensate the expansion of the metal parts like the valves and cam(shaft)s when they get hot. Therefore it is important to check and adjust valve clearence only on a cold engine! In theory, the clearence once set when the engine was cold is almost zero after the engine heated up properly. So your non existing clearence results in 2 problems: -wrong valve overlaps (intake is opened too early and closed too late ) -mechanical blocking into the valve train Modern cars compensate valve clearence with little, oil-pressurised pistons called hydraulic tappets. You should also check for your camshaft bearings because the may be damaged from the mechanical blocking as well as the timing chain tension. I hope I expressed myself somehow understandable and could help you a little.
adjusting the valves will probably fix it. By having zero clearance the valves aren't closing all the way. That means the engine isn't building as much compression as it needs to run.
Defiantlywill notice the engine running better. More power and easier starts. Had a zx10r that had tight valves. What a difference after the adjustment!
Heres how i am,: if a engine has something small bad with it like a dirty carb or ext. im fine, its an easy fix.... but when it gets deep into the engine i get a little scared.....
buy yourself 2 junk motors for cheap that have what you need to make one running one. don't put anymore than $50 into it and have no feelings for it. strip them both right back and build a motor. it's the best way to get your confidence up. they're not that scary after 2 or 3 rebuilds. read loads of books if that helps, understand different materials and why they're used in manufacturing and that will get you a long way. good luck my man!
Just a thought. It could be running too cold, you could be getting carb icing, the jets getting iced over, the way you could test the is by going out for a run without the electric fan on. This used to be a problem with 70's cars before water heated inlet manifolds.
I would take off the air cleaner and spray the starter fluid directly into the carburetor, all that cranking and the plugs were not even wet, I still think it could be a fuel issue. anyway good luck
The plugs were not wet because they are still firing and burning off the fuel. There is just not enough valve clearance for the engine to run because the compression is leaking past the valves. It doesn't matter how much fuel you get into the cylinder, if the valves are leaking off all the compression it is not going to run.
Its not still firing, it wouldn't burn all the fuel off unless it was running correctly, dry spark plugs show its not getting enough fuel, its most likely turning off once the bowls empty out and then he has to let it sit awhile until they slowly fill back up.
Im sure its the valve clearance. The reason there is clearance is when the engine heats up you have to have room for the metal to expand. Im wondering if after it warms up the tolerances go out of wack. Very intersting really excited for you to figure out the issue. (keep your head up you'll figure it out)
That'll do it. When the valve lash is too tight it will keep the valves open when they should be closed and that means that the engine will not have enough compression to run because it is leaking past the valves. Also, check to be sure that the timing is correct and make sure you take your valve clearance measurements on the base circle of the camshafts. The base circle is the side of the cam opposite of the lobe.
Hey Bud, this is the same problem I had with a poulan chainsaw that would start and run untill it warmed up, then would stop running. You basically have proven what the issue is using the feeler gage, the valve seats are worn out. The valves are barely closed when cold but as the stems warm up they lenghten and the valves remain slightly open, just enough to reduce compression enough for the engine to stop running. replace the valve seats and regrind or replace the valves and re-gap the rockers if it has any and the problem will be gone.
Zero clearance on the valves mean that are not fully closing and when heating up the valve sealing with get worse. Also, it is best to check the spark by just shorting the lead to ground because the spark gap resistance increases with compression, you need at least a 10mm (3/8 inch) long spark in open air.
Don't know what make of engine this is, but you must have valve clearance for the engine to work. Better loose than no clearance, not too loose mind you as it will be noisy, clattering sounds. No gap = loss of compression. You will not be able to check if valve clearances are to be done with engine up to temperature. Check clearance when engine is cold. You will need a micrometer to check the thickness of the shims that you get, and the ones that come out of the engine. I saw some very interesting mechanical reasons for loss of compression on many vehicles regarding valves when I was working as a mechanic, many years ago. Have fun!
Did you check both coils for spark? One of the coils could be going out which would cause it to fail once it gets hot/ to operating temp. I also noticed you have the coils mounted kind of close to the exhaust which could be causing this problem.
The engine needs to be leaning a certain way. Maybe you don't have it tilted down enough. What it seems like is happening to me is , the engine is pretty much straight up so gravity isn't taking the gas thru the engine like it should be. Street bike engines are crazy to mess with. When you let it sit for those 10 min and it runs again , gas if filling up in the carb enough to flow thru the engine like it should be. Then when the gas runs down low in the carb , it don't flow thru. Hope this helps. Big fan bro.
Keep in mind the specs for valve clearance are for a stone cold engine. However, with a warm or even hot engine, there should be at least some clearance. With a mildly warm engine .0015 should pass easily. Congrats on finding the problem!
If it ruins cold and won't when it heats up it is coils and sending unit shutting the motor off. Maybe low oil pressure sending unit. Motorcycle engines like a lot of air hitting the cylinder sleeves, for cooling the pistons. Try a different carb if that doesn't work look to coils, or if it even has spark to the plugs. Go from there. Check valves making sure they are opening and closing, pull the valve cover and check them and timing.
Welp, you found your problem. Once the valves warm up, the already tight clearance gets even tighter and then they don't close all the way. I bet if you take a cold compression reading and do it again when it's warmed up, it will show lower when warm. I wouldn't worry about it damaging anything. If you don't want to buy a shim kit, you can remove the ones that are in there and clearance them down yourself, just grind on the backside of the shim (not the face that contacts the cam) and you should be good. Run the exhaust valves a little more loose than the intakes. On a positive note, when you correct this problem the thing will have a bunch more power. :D Good luck.
Hehe, you found the problem;) I was just about to write this, just when the last part of the video came. If those engines heat up, the valve clearance gets even less, so you're leaking all your compression. That's the problem. Theoretically open valves can make a stream of burning gas shoot out the gap and cut your valve stem like a torch. But don't worry, that's only under high load and your valves are working, so this didn't happen
Clean the carbs. Modern gas degrades faster than you would think and those filters arnt fool proof. You might still have some cuttings or fine particals in the carbs from the dirty filter you removed. Also make sure that the engine is at top dead center of either the compression or exhaust stroke (depending on which valves and which cylinder your checking) and check the clearence of the CLOSED valve not the open one. Cams and valves are designed to interact so it's not going to damage the engine in the short term. It may just cause premature wear.
Valve clearance may be the issue... but if it runs for a few minutes then dies, maybe fuel is being used faster than it can flow into the carb bowl... restricted upstream somewhere. Between the time the engine dies and the time you open the drain plug, the bowl fills again...?
Adjust the valves, make sure to crank the engine to valve overlap when checking the valve clearances and when adjusting the valves that's the most important step
Hi, I'm interested in the lathe you built! It's very good, very good job! I would be interested in the measurements of this, or where I could get the plans If you have them, could you send them to me? From already thank you very much! p.d I do not speak English very well, so I use it with the Google translator
OK, I wouldnt say by running it with valves with too-close tolerance you did major damage, but you may have burned the valves or valve seats. I know you hate to hear this, but you really should buy a head gasket, pull the head off again, disassemble everything, clean the valves on the rotary wire brush on the grinder, and bead or sand blast the intake and exhaust ports around the seat areas, and clean everything with spray carb clean and inspect. if the valves and seats dont look burnt, then you should LAP them in by hand with lapping compound and the suction-cup lapping tool (both are cheap) - watch videos on how to do this, it's not bad- BUT THEN , when you reassemble everything and check and set your valve clearances you'll get an accurate measurement and set them properly - in the future, if you open and engine and the clearances are just close, but not solid like yours was, I'd say you could just shim it, but this engine was running this way when it was parked as a bike for god knows how long, and now all your test runs have been running it till it died dozens of times - I'd say do it right before you mess it up bad..... Remember, set the valve clearance to the larger number so .03-.08 is your range, set them to .08, because as it runs, over time the valves hammer themselves deeper into the head and close up that clearance- so if you set them to the larger gap of the acceptable range, you'll get more time out of your valve adjustment, before needing re-shimming-
This guy knows his stuff also i would say this is the problem I have 5 bikes 2 of them i have fully rebuilt (engine wise) I had the same problem with my 2008 honda crf150r the valves needed to be adjusted
I did not notice any type of choke system. I'm wondering if it may be closing and flooding the engine. Maybe try holding the accelerator open and see if it clears up and starts again.
Also you shortened the length of the exhaust pipe you might need to rejet the carburetor. I have a similar motor and I had the same problem when I shortened the pipe once it warmed up it would stall
Maybe when the engine gets up to temp the cylinder could expand and you loose compression, do a comp test on it. Also the valves could be not sealing properly
There you go. Once you get the correct ones it should be okay. It makes sense as in other videos of you driving it, it sounded like it was down on power. With them to tight it will hold open the valves once it warms up. With them hanging open you are losing vacuum with them carbs need to work properly!!
Hey man that could cause it because once the engine warms up and things expand the valves dont seat anymore and you dont make compression which is another test you should try take a cold and warm compression test
Valves need to be set, take the head off, disassemble the valves and there's a type of paste that you use to sand the valve seat then adjust the valves, you're losing compression due to a valve leak
Fuel cap vented? I think you may have mentioned it in a different video...but if not, it should probably be. Could be an intermittent electrical problem...points, magneto, or whatever else creates the spark. If it had spark, the starting fluid should have made something happen...if even a backfire.
If the valves were out it would still run but rough I think it's the plugs they can show a spark but when placed in the cylinder they will fail iv had this problem if not plugs I'd say your coil is breaking down when warm it runs till it's warm its electric problem it can only be plugs,coil,or stater breaking down I'd say plugs try them before anything
Before trying things out start with a FULL battery if it dosnt ref proper even starter fluid wont work Good luck and hurry I (and a 1000 more) wont to see You run that Beest
whith the heat the walves expand and they're open a tini litt Little bit.If this is the case you need to take of the head and watch if there is any dirt in the walfes and if it is they are dammeaged you can buy som special grease whith mini metal chips in it you put it in the walves and turn them to sand the walve seats (actualy it is not grease but i dont know the name of it) and if you ajust the walfes you need a stone cold engien
If you start it and it runs and shuts off after a warming up your piston ring or cylinders might be over sized when it heats up. Losing fuel and compression
Alright here's the dealio what you're going to check for is valve lash if there is too much or too little just tighten it up air fuel mixture you could have the wrong jet in there so check that as well check how much area getting in there too does the engine have a low oil cut off cuz if it does it could just be fouling out and being a terrible low oil cut off
The two main roll bars that go forward and backwards are not on the same spot on the front main roll bar ( from 0:00 on) Edit by spot I mean the same distance from the middle
OK. I am going to tell you your problem whether you guys say that this is it or not. before starting the engine take a compression test. measure that reading on a piece of paper. then run the engine let it stall then take another measurement by cranking the engine if it is less it is your top end going bad. when cold it has compression. when it is hot it loses compression making the engine incapable of running.
You can put an L-shaped rod vertical with the shifter and drill three holes forward neutral reverse whatever the case might be lift up the rod and Slide the handle forward spring-loaded Rod let go of the rod and it'll go in the hole to keep it in gear when you want to take it to the next year reach your finger down and pull the rod up that spring loaded pull back your leaver and drop the rod into the next hole you know what I mean Jelly Bean
Hey how frusrating is that ? Been there done that ! I was able to find some help with a guy on another channel ! look up Harve spooner he lives in New York and is a real stand up guy ! He is a genius with all things honda and others too ............. find his channel and message him. I think the guy thrives on fixing problems ! If the valves were too tight I don't think it would run even two minutes. You have the main things spark , looks like fuel and air as well as tiing sounds right because when you try to start it at first it does. one thing that I would try is after the 3 minutes or so annd then dies .... pull the plugs and pour fuel into the plug hole then put the plug back in and the try to start it....or see if it will start .... give that a try
Makes sense has enough compression to run cold but when it’s warm the valve stem expands with heat (getting longer) and hold the valves open to the point where it no longer has enough compression to run
you nailed it bro
Yeah, and it was backfiring also
thath could be the problem
i'm a mecanic from italy ( sorry about the grammar) if the engien is getting warm the walves expend just a tini little bit but thath could be enof so that the engien has no compression and the outtake walfe gets hotter and longer than when the piston gows down to suck fule up and it can not create a good vacumme and no good compresion
Keep up the good videos love the dune buggy one of the coolest things on UA-cam lately
An engine needs three things to run. Spark, fuel/air, and compression. Now you have a nice blue spark so that’s not the problem. Also because the engine didn’t run off the starting fluid there is nothing wrong with your fuel. If there was something wrong with the fuel the engine would have run off the staring fluid. So this leaves one thing, compression. It could be incorrectly adjusted valves or crack in the block but there is a compression leak or the just doesn’t have enough compression. I hope this helps
B
I hope my two boys grow up to be as smart as you are. Your going to make a great engineer someday.
I mentioned this many videos ago - I have a feeling you dont read all the comments? You have the left float bowl on the right carb and the right bowl on the left carb - if you swap them the drain screws will FACE OUTWARDS, and you'll be able to get to them easier
Hey ,
i am a mechanical engineer from germany and therefore know something about engines.
Valve clearence is needed to compensate the expansion of the metal parts like the valves and cam(shaft)s when they get hot. Therefore it is important to check and adjust valve clearence only on a cold engine! In theory, the clearence once set when the engine was cold is almost zero after the engine heated up properly. So your non existing clearence results in 2 problems:
-wrong valve overlaps (intake is opened too early and closed too late )
-mechanical blocking into the valve train
Modern cars compensate valve clearence with little, oil-pressurised pistons called hydraulic tappets.
You should also check for your camshaft bearings because the may be damaged from the mechanical blocking as well as the timing chain tension.
I hope I expressed myself somehow understandable and could help you a little.
adjusting the valves will probably fix it. By having zero clearance the valves aren't closing all the way. That means the engine isn't building as much compression as it needs to run.
Defiantlywill notice the engine running better. More power and easier starts. Had a zx10r that had tight valves. What a difference after the adjustment!
Heres how i am,: if a engine has something small bad with it like a dirty carb or ext. im fine, its an easy fix.... but when it gets deep into the engine i get a little scared.....
buy yourself 2 junk motors for cheap that have what you need to make one running one. don't put anymore than $50 into it and have no feelings for it. strip them both right back and build a motor. it's the best way to get your confidence up. they're not that scary after 2 or 3 rebuilds. read loads of books if that helps, understand different materials and why they're used in manufacturing and that will get you a long way. good luck my man!
Intake valves adjust the valves
Just a thought.
It could be running too cold, you could be getting carb icing, the jets getting iced over, the way you could test the is by going out for a run without the electric fan on.
This used to be a problem with 70's cars before water heated inlet manifolds.
I would take off the air cleaner and spray the starter fluid directly into the carburetor, all that cranking and the plugs were not even wet, I still think it could be a fuel issue. anyway good luck
The plugs were not wet because they are still firing and burning off the fuel. There is just not enough valve clearance for the engine to run because the compression is leaking past the valves. It doesn't matter how much fuel you get into the cylinder, if the valves are leaking off all the compression it is not going to run.
Its not still firing, it wouldn't burn all the fuel off unless it was running correctly, dry spark plugs show its not getting enough fuel, its most likely turning off once the bowls empty out and then he has to let it sit awhile until they slowly fill back up.
Im sure its the valve clearance. The reason there is clearance is when the engine heats up you have to have room for the metal to expand. Im wondering if after it warms up the tolerances go out of wack. Very intersting really excited for you to figure out the issue. (keep your head up you'll figure it out)
I think also that the valve and camshaft compartment should be wet of oil. Did you clean it before take the video?
That'll do it. When the valve lash is too tight it will keep the valves open when they should be closed and that means that the engine will not have enough compression to run because it is leaking past the valves. Also, check to be sure that the timing is correct and make sure you take your valve clearance measurements on the base circle of the camshafts. The base circle is the side of the cam opposite of the lobe.
You should try to also make a scoop on the top and make some kinda cover and tube to go from the scoop to the engine to cool it more
Dirtrider 1 thatd be cool, but i think a more powerful fan would be a better investment.
Hey Bud, this is the same problem I had with a poulan chainsaw that would start and run untill it warmed up, then would stop running. You basically have proven what the issue is using the feeler gage, the valve seats are worn out. The valves are barely closed when cold but as the stems warm up they lenghten and the valves remain slightly open, just enough to reduce compression enough for the engine to stop running. replace the valve seats and regrind or replace the valves and re-gap the rockers if it has any and the problem will be gone.
Small point, when the longest part of the individual valve cams are furthest away from the cup, then is when the gap will be biggest.
Adjust your valves dude!!!..It'll run like a champ once you do..
Zero clearance on the valves mean that are not fully closing and when heating up the valve sealing with get worse. Also, it is best to check the spark by just shorting the lead to ground because the spark gap resistance increases with compression, you need at least a 10mm (3/8 inch) long spark in open air.
maybe was a false neutral and popped in gear
Don't know what make of engine this is, but you must have valve clearance for the engine to work. Better loose than no clearance, not too loose mind you as it will be noisy, clattering sounds. No gap = loss of compression. You will not be able to check if valve clearances are to be done with engine up to temperature. Check clearance when engine is cold. You will need a micrometer to check the thickness of the shims that you get, and the ones that come out of the engine. I saw some very interesting mechanical reasons for loss of compression on many vehicles regarding valves when I was working as a mechanic, many years ago.
Have fun!
Did you check both coils for spark? One of the coils could be going out which would cause it to fail once it gets hot/ to operating temp. I also noticed you have the coils mounted kind of close to the exhaust which could be causing this problem.
The engine needs to be leaning a certain way. Maybe you don't have it tilted down enough. What it seems like is happening to me is , the engine is pretty much straight up so gravity isn't taking the gas thru the engine like it should be. Street bike engines are crazy to mess with. When you let it sit for those 10 min and it runs again , gas if filling up in the carb enough to flow thru the engine like it should be. Then when the gas runs down low in the carb , it don't flow thru. Hope this helps. Big fan bro.
Love the videos man keep up the great content
Keep in mind the specs for valve clearance are for a stone cold engine. However, with a warm or even hot engine, there should be at least some clearance. With a mildly warm engine .0015 should pass easily. Congrats on finding the problem!
If it ruins cold and won't when it heats up it is coils and sending unit shutting the motor off. Maybe low oil pressure sending unit. Motorcycle engines like a lot of air hitting the cylinder sleeves, for cooling the pistons. Try a different carb if that doesn't work look to coils, or if it even has spark to the plugs. Go from there. Check valves making sure they are opening and closing, pull the valve cover and check them and timing.
Welp, you found your problem. Once the valves warm up, the already tight clearance gets even tighter and then they don't close all the way. I bet if you take a cold compression reading and do it again when it's warmed up, it will show lower when warm. I wouldn't worry about it damaging anything. If you don't want to buy a shim kit, you can remove the ones that are in there and clearance them down yourself, just grind on the backside of the shim (not the face that contacts the cam) and you should be good. Run the exhaust valves a little more loose than the intakes. On a positive note, when you correct this problem the thing will have a bunch more power. :D Good luck.
Hehe, you found the problem;) I was just about to write this, just when the last part of the video came.
If those engines heat up, the valve clearance gets even less, so you're leaking all your compression. That's the problem.
Theoretically open valves can make a stream of burning gas shoot out the gap and cut your valve stem like a torch. But don't worry, that's only under high load and your valves are working, so this didn't happen
Clean the carbs. Modern gas degrades faster than you would think and those filters arnt fool proof. You might still have some cuttings or fine particals in the carbs from the dirty filter you removed.
Also make sure that the engine is at top dead center of either the compression or exhaust stroke (depending on which valves and which cylinder your checking) and check the clearence of the CLOSED valve not the open one. Cams and valves are designed to interact so it's not going to damage the engine in the short term. It may just cause premature wear.
Valve clearance may be the issue... but if it runs for a few minutes then dies, maybe fuel is being used faster than it can flow into the carb bowl... restricted upstream somewhere. Between the time the engine dies and the time you open the drain plug, the bowl fills again...?
Adjust the valves, make sure to crank the engine to valve overlap when checking the valve clearances and when adjusting the valves that's the most important step
That’s why the bike was in the junk yard
Hi, I'm interested in the lathe you built! It's very good, very good job!
I would be interested in the measurements of this, or where I could get the plans
If you have them, could you send them to me?
From already thank you very much!
p.d I do not speak English very well, so I use it with the Google translator
Defoe needs an exhaust. Not having one is pretty much guaranteed to be causing problems of some kind.
I have a gsxf750 I wanna make a gokart with, can't wait!
If you don't have any bruned valves, it'll run so smooth after you ajusted the clearence!!
did you checked the jets in the carb ?
OK, I wouldnt say by running it with valves with too-close tolerance you did major damage, but you may have burned the valves or valve seats. I know you hate to hear this, but you really should buy a head gasket, pull the head off again, disassemble everything, clean the valves on the rotary wire brush on the grinder, and bead or sand blast the intake and exhaust ports around the seat areas, and clean everything with spray carb clean and inspect. if the valves and seats dont look burnt, then you should LAP them in by hand with lapping compound and the suction-cup lapping tool (both are cheap) - watch videos on how to do this, it's not bad- BUT THEN , when you reassemble everything and check and set your valve clearances you'll get an accurate measurement and set them properly - in the future, if you open and engine and the clearances are just close, but not solid like yours was, I'd say you could just shim it, but this engine was running this way when it was parked as a bike for god knows how long, and now all your test runs have been running it till it died dozens of times - I'd say do it right before you mess it up bad..... Remember, set the valve clearance to the larger number so .03-.08 is your range, set them to .08, because as it runs, over time the valves hammer themselves deeper into the head and close up that clearance- so if you set them to the larger gap of the acceptable range, you'll get more time out of your valve adjustment, before needing re-shimming-
This
This guy knows his stuff also i would say this is the problem I have 5 bikes 2 of them i have fully rebuilt (engine wise) I had the same problem with my 2008 honda crf150r the valves needed to be adjusted
I did not notice any type of choke system. I'm wondering if it may be closing and flooding the engine. Maybe try holding the accelerator open and see if it clears up and starts again.
I would also check the timing advance mechanism to make sure it's not locked up
Also you shortened the length of the exhaust pipe you might need to rejet the carburetor. I have a similar motor and I had the same problem when I shortened the pipe once it warmed up it would stall
Maybe when the engine gets up to temp the cylinder could expand and you loose compression, do a comp test on it. Also the valves could be not sealing properly
There you go. Once you get the correct ones it should be okay. It makes sense as in other videos of you driving it, it sounded like it was down on power. With them to tight it will hold open the valves once it warms up. With them hanging open you are losing vacuum with them carbs need to work properly!!
Love the build 3rd place
Hey man that could cause it because once the engine warms up and things expand the valves dont seat anymore and you dont make compression which is another test you should try take a cold and warm compression test
Valves need to be set, take the head off, disassemble the valves and there's a type of paste that you use to sand the valve seat then adjust the valves, you're losing compression due to a valve leak
The Springs might be getting weak on the valves when it gets warm in the valves are not opening right
Maybe you should try and put a vent on the gas tank cap
Fuel cap vented? I think you may have mentioned it in a different video...but if not, it should probably be. Could be an intermittent electrical problem...points, magneto, or whatever else creates the spark. If it had spark, the starting fluid should have made something happen...if even a backfire.
Hi. Where can i get the parts?
Once it stalls like that crank it over a couple of times and see if the plugs are wet it could be a fuel problem
If the valves were out it would still run but rough I think it's the plugs they can show a spark but when placed in the cylinder they will fail iv had this problem if not plugs I'd say your coil is breaking down when warm it runs till it's warm its electric problem it can only be plugs,coil,or stater breaking down I'd say plugs try them before anything
Could it be choking and not getting enough air?
May you put a tubo on if you will get it running?😃😃
I think you should just pull the engine and do a clean up and rebuild so you can do it right
Cool buggy
Nice investigation looks like that maybe the issue i say
Does it have a timing chain? Maybe the chain is worn out?!
Check the compression with a compression gauge cold and hot!
Put you hand over the carbs and see if you feel compression blowing out of it. If so adjust your valves.
It could be jets if the spark plugs are super dry it could be getting to much or too little back pressure
I had the same problem with my centrifugal clutch you get 2 min and motor randomly dies on brand new motor
Before trying things out start with a FULL battery if it dosnt ref proper even starter fluid wont work Good luck and hurry I (and a 1000 more) wont to see You run that Beest
valves tightin up when warmed up gs 450's are known for it there shim under bucket so have fun
Interested in the outcome of this problem.
Is there a possibility that’s it has a low oil sensor and it’s just barley doesn’t have enough oil in it to kick the switch
whith the heat the walves expand and they're open a tini litt Little bit.If this is the case you need to take of the head and watch if there is any dirt in the walfes and if it is they are dammeaged you can buy som special grease whith mini metal chips in it you put it in the walves and turn them to sand the walve seats (actualy it is not grease but i dont know the name of it) and if you ajust the walfes you need a stone cold engien
When you rebuilt the engine you use the old Rings you should use new rings on the piston
A rebuild kit is probably expensive for an engine like that!
If you start it and it runs and shuts off after a warming up your piston ring or cylinders might be over sized when it heats up. Losing fuel and compression
I thought motorcycles needed radiators
It could also be a head gasket
Your engine needs to be on the right stroke to check each valve
Alright here's the dealio what you're going to check for is valve lash if there is too much or too little just tighten it up air fuel mixture you could have the wrong jet in there so check that as well check how much area getting in there too does the engine have a low oil cut off cuz if it does it could just be fouling out and being a terrible low oil cut off
It might be something with the ignition overheating or maybe the coils
All that good welding just to let it rust? Why no paint
Mixture screws you need to tune it up
get a book for that enegen
When the engine get hot the valves expand and therefore the valves won't seat properly
I had a problem like this and we had to get a new thrust clutch on the starter Motor
There's probably a reason the bike that motor came off of was scraped
The two main roll bars that go forward and backwards are not on the same spot on the front main roll bar ( from 0:00 on)
Edit by spot I mean the same distance from the middle
What happens if you take the gascap off. It can make an vaccume
Did you check the air screw on the carb
if the valves strayed open the engine would crank faster then normal due to no compression
That thing looks like a sand rail
OK. I am going to tell you your problem whether you guys say that this is it or not. before starting the engine take a compression test. measure that reading on a piece of paper. then run the engine let it stall then take another measurement by cranking the engine if it is less it is your top end going bad. when cold it has compression. when it is hot it loses compression making the engine incapable of running.
Motorcykle carburators does not have an acceleration pump so there's absolutely no point pumping the gas pedal / throttle ..it doesnät do anything.
You can put an L-shaped rod vertical with the shifter and drill three holes forward neutral reverse whatever the case might be lift up the rod and Slide the handle forward spring-loaded Rod let go of the rod and it'll go in the hole to keep it in gear when you want to take it to the next year reach your finger down and pull the rod up that spring loaded pull back your leaver and drop the rod into the next hole you know what I mean Jelly Bean
What volor are spark plugs after 2 mins of running?
Might be headgaskets?
Hey how frusrating is that ? Been there done that ! I was able to find some help with a guy on another channel ! look up Harve spooner he lives in New York and is a real stand up guy ! He is a genius with all things honda and others too ............. find his channel and message him. I think the guy thrives on fixing problems ! If the valves were too tight I don't think it would run even two minutes. You have the main things spark , looks like fuel and air as well as tiing sounds right because when you try to start it at first it does. one thing that I would try is after the 3 minutes or so annd then dies .... pull the plugs and pour fuel into the plug hole then put the plug back in and the try to start it....or see if it will start .... give that a try
Check the timing key on the flywheel
Só falo potugues
you need to check both sides for spark not just one side is cylinder one is down it wont run
if the walve clearence is too smal it coud smash the piston in to the walves
Dude need to clean that wiring up
Looks way rich black plug
cheek youe wires man sounds like something is grounding out
take the air filter off is another thing to try
Battery is not spinning it over fast enough with the first thing you tried with the starter fluid
maybe the solenoid is shot or timings off