@@zaneclark5226 to be fair it could work but It just isn't very likely centering them would put them at less of a disadvantage and make the path even on both sides
That would be a great idea in a perfect world- but not doable with off the shelf PVC drainage fittings. this will work, not perfectly, but it will work. I think I could build it from out of the bin parts, but to balance the runner length, I would have to have intake runners 6-9 inches long, baloney sliced so that I can bring the two pipes together as one round opening and use a coupler to make the end piece. It would need the carbs directly supported by some more structure- those rubber boots won't take much vibration to fall off with the carbs out on a longer "lever"- and they would be out in an area that already has a lot of stuff in the way.FR
IIRC the C& C rig was the same offset Migs had- it did have some balancing problems, but it ran much better than the constant velocity OEM's let it. Two of my last bikes were 750 H's - tuning, even with the stock carbs in well maintained shape was a pain- after they sit for 10-15 years with stale gas in them a rebuild needs a boil out of the body and blow all the passages out- my luck with that wasn't the best- my next door neighbor was the shop foreman for the Honda dealer and could make them sing- but he used a professional boil out and clean to get the crap out of the secondary passages and such. The air box everybody is talking about was Honda's answer to stabilize these carbs- the slide throttle carbs aren't as sensitive to restriction on the intake side, so the clamp on air filters will likely do what's needed. FWIW, you are correct about the fuel air mixture being off a bit- there just isn't anyway to build and equalized manifold from off the shelf PVC plumbing parts- good enough to run pretty well is what you can get- $200-$400 may find you a good set of used carbs for a 750 today- or the may be a crapped out as the ones he has- and then he will need that air box.FR
Carbs need to be in the centre as one of the 2 cylinders are pulling more fuel on each carb and just slap some pod filters on will be fine and when compression testing the throttle needs to be wide open
Make sure the outer 2 elbows going to the outer 2 cylinder s have a smooth transition. C&C's cart runs on 2 cylinders at high rpm because the rear two aren't getting air
They need to learn this stuff and its kinda common sense, they probably are running more lean than stock by having the air make that sharp turn, honestly what I would do is just run 4 different carbs than stock and have 4 separate egt sensors on each exhaust exit for each clyinder and tune each carb just right, although would be more difficult that's how you do it right
Good job buddy, keep it up and stop worrying about what other people are saying and tellin you to do, youll learn from your own mistakes, keep the vids comin man its nice to see a young fella doin some mechanic work instead of gettin their keyboards full of jizz!!!
Finally sounds halfway descent bud! Keep up the good work. I could tell you were getting really frustrated but kept at it. Im glad you took some time and figured it out. Never give up! Oh, and always test comoression with wide open throttle!!
Ok migs let me start off by saying one day I was surfing the internet and I came across your channel so I watched a few videos and like that I was instantly hooked. Let me put it like this if it wasn't for you I would probably not be really in to dirtbiking. You are my inspiration dude I look up to you and I really appreciate you more than you than you know so I am going to promote your channel all across my social media
Migs what you got to do for the return is drill a hole in the tank and tap a fitting in. Done the same thing and it works a lot better than a hole in the cap and looks more professional. Keep up the good work!
Hey man I must say I've been watching you do these videos all year on this nascar I'm so proud of how you've done and explain everything I can't even wait to see this beast run and to have the original Speedo is like so top stuff man well done keep up good work man your a legend 🤘
You only need the airbox for the 4 carbs, because they need to all be synced the same. I had the same issue with my bike, but since you have 2 carbs that are easier to tune, you should only need pod filters. Hope this helps
Yes and valve lash can most likely be a issue as well. A engine that's sat for so long and then run like he does I could see it being valve lash even after a topend rebuild
I agree with Backwoods MX. I would redo the plumbing for the carbs so they are centered between each cylinder for better airflow. And you can definitely go with the pods 1 pod filter per carburetor. Those engines do not require an airbox. The reason those engines come with an air box on the motorcycle is 4 rain situations where you are riding your motorcycle and get caught in the rain. But I don't suspect you will be riding it through water so you should be okay. Plus the pods get better airflow through the carbs and with half the exhaust missing from its original design you actually have maximum airflow which this engine can achieve with the cam setup it has
I would do individual air filters, don’t do an air box because it’ll be robbing and you’ll have to cut out of your shell, but if you do the separate filters you can use some elbow tubing and set each one lower, and you won’t have to cut out the shell for them to fit
Great video. I’m thinking of doing the same to all three of my bikes. ( 2 to 1 carbs on the two viragos and 4 to 2 carbs on the xj750 )One of which has a similar motor (1982 Yamaha xj750). My main worry with switching the manifolds to PVC is that I worry it’ll melt from the heat of the engine where it connects
To provide a straighter inlet path you could try a PVC wye with 2 tight 22.5's on the engine side and another one between the carb and wye. Schedule 80 PVC in dark grey might provide a works factory illusion. PVC likes a boiling water soak followed by stretching and holding at size then cooling with water to set. Something to be aware of for most PVC is after stretching with heat. If you reheat part it will return to very near original size. A good clamping force can be achieved this way but you have to pay attention. Peace and good luck.
Use a spray bottle on the exuast pipes to see if you have combustion. You won't get burnt. A little trick I learned from watching Nick's Garage on UA-cam. Make an airbox out of aluminum with a K&N filter like on a car with twin carbs.
Anything 110 and up is wonderful for that motor I'm sure it would run just fine I've had Motors wear the compression test came out at 90 PSI per cylinder and it still ran fine the 110 and up is beautiful
My seca 550 has a airbox and I got told if I don't run one without it it will mess up air fuel rasio sometimes and it will lift the chance of bigger like Rick's or something hitting those pod filters and going into the engine and wrecking it
Pods will be fine on the dual flat slide carbs,the stock cb750 carbs are kehin cv carbs they need an airbox to create the vacuum needed to lift the slide.
Next time in a pinch you could open the two small clamps up and put them together to make a big one. I'm a plumber and been there and done that. Good job buddy.
So velocity stacks or pods will work if your running wide open most of the time they tend to not be as good for mid and low idle and airbox would probably be better suited to your application
You can loosen 2 hose clamps all the way and combine them together to make one thats twice the size, exactly same principal as stringing a few zipties together
Like your vids, keep it up. One thing i noticed is the kink in you fuel line, fix the little things now, it'll save you headaches in the future and dont feel rushed to complete somthing, looking forward to future content 👍
Does each cylinder once without doing anything to the cylinder after doing so go back and put like a half of a cap of oil in that cylinder and test it again if there's compression goes up it means you have a cylinder problem if the compression stays the same and your compression is still low it would mean you have a valve problem instead of a ring problem
Cycle exchange has the carb, Y intake manifolds and throttle cable in one kit for that but they told me the 4 into 2 wont work well on the cv carb bikes..
i would swap the right coil for the left coil and see if the problem transfers to the outer cylinders if so then deffo coil problem if it does not change then pick or points problem
Also I would check your valve lash. Having the valves perfect makes a huge difference in how the engine runs if there's any leak or misstep in timing with the valves the engine will not run as efficiently as it can but I'm sure you know that already I would just double-check
It Will need adjusting and probably jetting with airbox or pods. But air filter wont need to be connected to run right. And pods o airbox they Will still run pretty much the same after adjusting
Hey so that's way cool it worked out for you. I just now read the part that this was 4 years old. That's cool though I'm trying to do the same thing on a triple cylinder where I make 2 carbs go to 3 cylinders. Do you think it'll work the same way if I kind of do that little setup that you did but only have two carbs instead of three carbs?
it doesn't matter what you do with the air filters long as the carbs are tuned with them on but no matter what you do you are going to have 2 rich and 2 lean cylinders because you have 2 different runner lengths on the carbs
Cars and cameras did this kind of set up on carbs if it was mine I would make a straight peace for each carb fill like it would work well and then can run carb of choice and they is ways to connect throttle cable in to one
Hey, I know that you've been wanting to be able to see ur tach signal. What if u just mounted the one u have next to ur head and then put on a review mirror that makes it so u can see it. Idk, just a thought
For a good accurate reading on all cylinders on your motor you should let the engine just rotate 3 complete rotations and then do it on all of them so you get the same reading and at 3 rotations should be plenty of compression to pump it up enough to give you a accurate compression test
You wont get the same output with 2 carbs since all the cylinders arent able to get their own tune but with the two carb set up id put them between cylinder 1 and 2 and cylinders 3 and 4 so that its more equal gas output per cylinder. Just a tip for ya migs youre doin great
Go to cars and cameras and watch there build on the cross cart and they had same issue whith air box and same moter so they tried individual air breathers and ended up making a PVC airbox so check them out and it may answer alot of your questions
Man I can't believe you have gone this far with using the same plugs that came with it, and it you have a cracked coil and the wires pull out of the plugs then fix it lol
I would get the pods. If you look at flat track bikes they run the pods on their 750s. And the bike hit about 150 on a mile track. I would get the pods it would be better air flow to.
migs you need a new gas tank. i have the same one. brand new it leaks because there is no seal on the gas cap. after less than a month, the studs broke and i had to get a new one. they dent really easily, and theres no way that i have found to remove them. just trust me on this one, migs
carb wise these where the best carbs to go for unlike the other they dont need the vacuume from having a filter on to work correctly the slider inside the carb moves from a cable instead think also you could prob get it down to a single carb with another pvc t peace
You need an air box if running the original carbs. Pods should be fine with that setup. I don't like those 90s in your intake. The tubes should be even.
This one just like the cars and cameras one is going to end up eating itself starving cylinders like that. Would help if you had a full exhaust as well.
How you did this may cause fuel starvation for the outer cylinders. I would recommend redoing this and centering the carb between both cylinders.
Backwoods Mx everyone needs to like this so he sees it. Outer two will be really lean
Yes
Yeah i dont know why he thinks the fuel will just go through the turn especially at high rpm
@@zaneclark5226 to be fair it could work but It just isn't very likely centering them would put them at less of a disadvantage and make the path even on both sides
That would be a great idea in a perfect world- but not doable with off the shelf PVC drainage fittings. this will work, not perfectly, but it will work. I think I could build it from out of the bin parts, but to balance the runner length, I would have to have intake runners 6-9 inches long, baloney sliced so that I can bring the two pipes together as one round opening and use a coupler to make the end piece. It would need the carbs directly supported by some more structure- those rubber boots won't take much vibration to fall off with the carbs out on a longer "lever"- and they would be out in an area that already has a lot of stuff in the way.FR
More fuel will be going to the cylinder with the straight pvc pipe. Reason cars and cameras did theirs in the centre- like a “T”
IIRC the C& C rig was the same offset Migs had- it did have some balancing problems, but it ran much better than the constant velocity OEM's let it. Two of my last bikes were 750 H's - tuning, even with the stock carbs in well maintained shape was a pain- after they sit for 10-15 years with stale gas in them a rebuild needs a boil out of the body and blow all the passages out- my luck with that wasn't the best- my next door neighbor was the shop foreman for the Honda dealer and could make them sing- but he used a professional boil out and clean to get the crap out of the secondary passages and such. The air box everybody is talking about was Honda's answer to stabilize these carbs- the slide throttle carbs aren't as sensitive to restriction on the intake side, so the clamp on air filters will likely do what's needed. FWIW, you are correct about the fuel air mixture being off a bit- there just isn't anyway to build and equalized manifold from off the shelf PVC plumbing parts- good enough to run pretty well is what you can get- $200-$400 may find you a good set of used carbs for a 750 today- or the may be a crapped out as the ones he has- and then he will need that air box.FR
Carbs need to be in the centre as one of the 2 cylinders are pulling more fuel on each carb and just slap some pod filters on will be fine and when compression testing the throttle needs to be wide open
Was just about to comment this ^
That wrong Glyn unless all the cylinders pulsing at same time and yes right way to do a compression testing the throttle needs to be wide open
throttle has to be wide open to compression test thats why your getting low readings
to do compression open throttle fully or remove the carb
Ok thanks for letting me know, once I get the throttle cables installed, I’ll check it again at full throttle 👍🏻
@@motomigsofficial with how close the readings where they seem ok
Make sure the outer 2 elbows going to the outer 2 cylinder s have a smooth transition. C&C's cart runs on 2 cylinders at high rpm because the rear two aren't getting air
he has bigger carbs so it shouldn't be as big of a problem
@@joshwillardturtleman12354 yeah but it'll still be a problem. The air can't make that sharp of a turn at high speeds
Very true he needs to see this
They need to learn this stuff and its kinda common sense, they probably are running more lean than stock by having the air make that sharp turn, honestly what I would do is just run 4 different carbs than stock and have 4 separate egt sensors on each exhaust exit for each clyinder and tune each carb just right, although would be more difficult that's how you do it right
@@jok3yjesu339 yeah that would make way more sense
Good job buddy, keep it up and stop worrying about what other people are saying and tellin you to do, youll learn from your own mistakes, keep the vids comin man its nice to see a young fella doin some mechanic work instead of gettin their keyboards full of jizz!!!
Can't wait to see you finally get this kart running keep up awesome job you will be able to fix anything after this
center the carbs between the 2 cilinders that they are giving fuel to
Yea I reckon the inner cylinders will be getting more or better air and fuel than the outer ones
buster STIG yes is agree, not good for the engine :/
Finally sounds halfway descent bud! Keep up the good work. I could tell you were getting really frustrated but kept at it. Im glad you took some time and figured it out. Never give up! Oh, and always test comoression with wide open throttle!!
Ok migs let me start off by saying one day I was surfing the internet and I came across your channel so I watched a few videos and like that I was instantly hooked. Let me put it like this if it wasn't for you I would probably not be really in to dirtbiking. You are my inspiration dude I look up to you and I really appreciate you more than you than you know so I am going to promote your channel all across my social media
Way better option than the stock 4, this is going to make some power
Migs what you got to do for the return is drill a hole in the tank and tap a fitting in. Done the same thing and it works a lot better than a hole in the cap and looks more professional. Keep up the good work!
Hey man I must say I've been watching you do these videos all year on this nascar I'm so proud of how you've done and explain everything I can't even wait to see this beast run and to have the original Speedo is like so top stuff man well done keep up good work man your a legend 🤘
I am very surprised with the better engine performance with these carburetors ... good job !
76oo
I’m really surprised too! Thanks!!
Looking good sounds good keep up the good work
Thanks!
Just get two uni foam air pods, you onely need the air box if you have the old carbs the the vacuum chamber. I hope this helps! I love the build! 😍😊
I Would probably make one big air filter, bc I don’t know if it can make a difference if one of the filters is a little harder to breathe thru.
Can't wait to see u drive that little beast
You only need the airbox for the 4 carbs, because they need to all be synced the same. I had the same issue with my bike, but since you have 2 carbs that are easier to tune, you should only need pod filters. Hope this helps
I dont ever remember him checking valve lash bout 100% positive that's the other reason you have low compression..
All 4 cylinders were above 100 psi.
Compression is fine.
Yes and valve lash can most likely be a issue as well. A engine that's sat for so long and then run like he does I could see it being valve lash even after a topend rebuild
I agree with Backwoods MX. I would redo the plumbing for the carbs so they are centered between each cylinder for better airflow. And you can definitely go with the pods 1 pod filter per carburetor. Those engines do not require an airbox. The reason those engines come with an air box on the motorcycle is 4 rain situations where you are riding your motorcycle and get caught in the rain. But I don't suspect you will be riding it through water so you should be okay. Plus the pods get better airflow through the carbs and with half the exhaust missing from its original design you actually have maximum airflow which this engine can achieve with the cam setup it has
Wow that sounds sooo good can’t wait for more videos
How do you not have 1m + subs yet so underrated
Nathan Alexander because he doesn’t know what he’s doing, it’s the jankiest channel ever but i still watch
I would do individual air filters, don’t do an air box because it’ll be robbing and you’ll have to cut out of your shell, but if you do the separate filters you can use some elbow tubing and set each one lower, and you won’t have to cut out the shell for them to fit
Great video. I’m thinking of doing the same to all three of my bikes. ( 2 to 1 carbs on the two viragos and 4 to 2 carbs on the xj750 )One of which has a similar motor (1982 Yamaha xj750). My main worry with switching the manifolds to PVC is that I worry it’ll melt from the heat of the engine where it connects
To provide a straighter inlet path you could try a PVC wye with 2 tight 22.5's on the engine side and another one between the carb and wye. Schedule 80 PVC in dark grey might provide a works factory illusion. PVC likes a boiling water soak followed by stretching and holding at size then cooling with water to set. Something to be aware of for most PVC is after stretching with heat. If you reheat part it will return to very near original size. A good clamping force can be achieved this way but you have to pay attention.
Peace and good luck.
Use a spray bottle on the exuast pipes to see if you have combustion. You won't get burnt. A little trick I learned from watching Nick's Garage on UA-cam. Make an airbox out of aluminum with a K&N filter like on a car with twin carbs.
Damn, nice to see this thing coming together!
Make a single air box and the intake pressures will equalize and run its best.
Two hose clamps can be assembled into one if you're ever in a pinch.
Anything 110 and up is wonderful for that motor I'm sure it would run just fine I've had Motors wear the compression test came out at 90 PSI per cylinder and it still ran fine the 110 and up is beautiful
The original carb setup needed an air box. You can use pods on this setup. If at all possible center the carbs between the cylinders.
My seca 550 has a airbox and I got told if I don't run one without it it will mess up air fuel rasio sometimes and it will lift the chance of bigger like Rick's or something hitting those pod filters and going into the engine and wrecking it
We need to hear it with full idle to see if it starts to break up. Very impressive work man.
Pods will be fine on the dual flat slide carbs,the stock cb750 carbs are kehin cv carbs they need an airbox to create the vacuum needed to lift the slide.
Next time in a pinch you could open the two small clamps up and put them together to make a big one. I'm a plumber and been there and done that. Good job buddy.
The single filters will work just fine.
So velocity stacks or pods will work if your running wide open most of the time they tend to not be as good for mid and low idle and airbox would probably be better suited to your application
You can loosen 2 hose clamps all the way and combine them together to make one thats twice the size, exactly same principal as stringing a few zipties together
What brand of carbs and what's the jetting in them?? I have the same motor, was thinking of dual setup
Like your vids, keep it up. One thing i noticed is the kink in you fuel line, fix the little things now, it'll save you headaches in the future and dont feel rushed to complete somthing, looking forward to future content 👍
Does each cylinder once without doing anything to the cylinder after doing so go back and put like a half of a cap of oil in that cylinder and test it again if there's compression goes up it means you have a cylinder problem if the compression stays the same and your compression is still low it would mean you have a valve problem instead of a ring problem
That thing gonna fly man when it finished!!
Cycle exchange has the carb, Y intake manifolds and throttle cable in one kit for that but they told me the 4 into 2 wont work well on the cv carb bikes..
How's you project now ? Hope you have update
i would swap the right coil for the left coil and see if the problem transfers to the outer cylinders if so then deffo coil problem if it does not change then pick or points problem
Dude it sound so mean now that was sick
This is such an awesome build I wish I had the money for a project like this.
Also I would check your valve lash. Having the valves perfect makes a huge difference in how the engine runs if there's any leak or misstep in timing with the valves the engine will not run as efficiently as it can but I'm sure you know that already I would just double-check
Did you do carb kits for all the carbs half the time it's that rubber diaphragm for the needle
It Will need adjusting and probably jetting with airbox or pods. But air filter wont need to be connected to run right. And pods o airbox they Will still run pretty much the same after adjusting
Put cable ties around where the spark plug boot connects into the wire and wore connects to the coilpack. This will prevent them from vibrating loose.
You can just stick you fingers in both carbs to push the slides up and rev it
Hey so that's way cool it worked out for you. I just now read the part that this was 4 years old. That's cool though I'm trying to do the same thing on a triple cylinder where I make 2 carbs go to 3 cylinders. Do you think it'll work the same way if I kind of do that little setup that you did but only have two carbs instead of three carbs?
individual pods will be fine with this carb set up once you change the carbs the factory airbox is eliminated
i would of tried the left outlet of the regulator to the left carb and thr right one to the right carb kinda like a fuel rail on a v8 injection system
i would also run some cracket from bottom frame rail to the carbs to support them
you need to get you a battery jump box. things are super handy around the house
it doesn't matter what you do with the air filters long as the carbs are tuned with them on but no matter what you do you are going to have 2 rich and 2 lean cylinders because you have 2 different runner lengths on the carbs
also make sure the exhaust is made and finished before tuning
Just a little note, If you spill gas on a wood floor you have to clean it up because if you dont the gas will eat away at the wood and rot it.
It sounds like a frickin monster truck!
Cars and cameras did this kind of set up on carbs if it was mine I would make a straight peace for each carb fill like it would work well and then can run carb of choice and they is ways to connect throttle cable in to one
Little tip if u open up the hose clamp connect another to it an bingo u have 1 big enough 👍🏻
Pods just take some extra tuning, although if you're off-roading it I would enclose them from mud and dirt
Hey, I know that you've been wanting to be able to see ur tach signal. What if u just mounted the one u have next to ur head and then put on a review mirror that makes it so u can see it. Idk, just a thought
For a good accurate reading on all cylinders on your motor you should let the engine just rotate 3 complete rotations and then do it on all of them so you get the same reading and at 3 rotations should be plenty of compression to pump it up enough to give you a accurate compression test
You wont get the same output with 2 carbs since all the cylinders arent able to get their own tune but with the two carb set up id put them between cylinder 1 and 2 and cylinders 3 and 4 so that its more equal gas output per cylinder. Just a tip for ya migs youre doin great
get pods with partial plastic covers that go around the filter they give better back pressure
Use the pods because you are riding it on the road soo there wont be alot of dust and things so they should be pefect and save space
Go to cars and cameras and watch there build on the cross cart and they had same issue whith air box and same moter so they tried individual air breathers and ended up making a PVC airbox so check them out and it may answer alot of your questions
Does anyone know if that same 34mm dual carb set up would work on a sohc 650?
I would have made a manifold with all 4 intake ports connected together and placed the 2 carbs feeding all 4 cylinders, And yes make an air box...
Agreed
Did the fuel eventually melt the plasic manifold?
Just get small cold air intakes they make them for carburetors they work great I have it on my 4 wheeler
Just put individual air filters on the carbs and try to redo the carb manifold because the outer carbs are probably starving for fuel.
You can get a dual air filter for it
In my opinion, as long as the engine gets clean air it should run fine.
Whats up bro you had a nice built!! What size of carburetor you use for this kind of set up?? Thanks
Man I can't believe you have gone this far with using the same plugs that came with it, and it you have a cracked coil and the wires pull out of the plugs then fix it lol
Ill give it to you,you are very creative
Check cars and cameras cross cart they used the pod filters and it runs fine
I would get the pods. If you look at flat track bikes they run the pods on their 750s. And the bike hit about 150 on a mile track. I would get the pods it would be better air flow to.
migs you need a new gas tank. i have the same one. brand new it leaks because there is no seal on the gas cap. after less than a month, the studs broke and i had to get a new one. they dent really easily, and theres no way that i have found to remove them. just trust me on this one, migs
Young Brotherman,the runners need to be equal length,that PVC pipe heats and bends well 😎
Carsandcameras I think just did individually pods
carb wise these where the best carbs to go for unlike the other they dont need the vacuume from having a filter on to work correctly the slider inside the carb moves from a cable instead think also you could prob get it down to a single carb with another pvc t peace
I race lawnmowers we don’t run a air box we run separate air filters you need to open the throttle to check compression
It sounds so good
You need an air box if running the original carbs. Pods should be fine with that setup. I don't like those 90s in your intake. The tubes should be even.
Make an airbox with a scoop that goes on top of the roof of the half scale nascar
that style carb doesn't need an air box just put a filter on each carb
Do individual pods man u would need a box of u had 4 carbs but since u did the 2 carb conversion u can use 2 separate pods man
Air pods no problem.. may have to play with jetting
You need to get a jump box for when your batteries die
This one just like the cars and cameras one is going to end up eating itself starving cylinders like that. Would help if you had a full exhaust as well.
5:50 he is speaking 2019 high school students language
Airpods are the move
Cylinder 1 and 4 are going to be running lean because of the turns on the plastic intake
Your making really good progress but I feel like you should have tested the chain and the sprocket a little more!! But keep up the good work
Can u just get this together already lol been like what a yr already