Full blown race build with a 212 4 stroke stroker motor that was on a racing go kart running on alcohol. So much compression I cant even pull start it

I’ll get pictures of the manual clutch for you guys shortly. I’m just showing off my up coming bike build. I’m not asking any questions. This bike has so much compression that it requires a go kart starter box.
 
DieselTech said:
Have you seen these guys running the gx390 honda with the big super SBN mikuni pumper carb? Guy around New York area made if I remember correctly 86.6hp on a fully custom gx390. Still the a record holder in his race class I believe. I think that gx390 cost $8000 to build.
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Yeah it’s insane how much power they squeeze out of these little motors. They even go as far as reinforcing the block. In some cases they use billet blocks so it can keep up with the internals of the motor.
 
MendezMotorizedBicycles said:
Yeah it’s insane how much power they squeeze out of these little motors. They even go as far as reinforcing the block. In some cases they use billet blocks so it can keep up with the internals of the motor.
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Yeah if you are making ungodly compression & running for a extended period of time, they will blow the whole cylinder & head off the block. So they weld a spine on top of the block.
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Sidewinder Jerry said:
It may be very exactly what you're talking about. Basic mechanical diagnostics procedures dictates to eliminate the simple and easy to fix as a cause, before pursuing the complex.
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I would normally agree, but there is nothing to diagnose. He stated the hard pull start due to high compression for contextual purposes, not diagnostic. The subsequent post never mentions it again. That is why @DAMIEN1307 was confused with your first response. Nothing to diagnose.
 
DieselTech said:
No broken legs or cracked shins I hope. Or thrown over the handle bars. 🤣😂🤣
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Nah, I'm too big for any of that. The bike breaks before I do.
DieselTech said:
Have you seen these guys running the gx390 honda with the big super SBN mikuni pumper carb? Guy around New York area made if I remember correctly 86.6hp on a fully custom gx390. Still the a record holder in his race class I believe. I think that gx390 cost $8000 to build.
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Yeah, I have seen some of those builds. I have seen a couple of nitro fueled examples too. Gotta love those oxygenated fuels.
 
ImpulseRocket said:
I would normally agree, but there is nothing to diagnose. He stated the hard pull start due to high compression for contextual purposes, not diagnostic. The subsequent post never mentions it again. That is why @DAMIEN1307 was confused with your first response. Nothing to diagnose.
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So are you saying it's no longer hard to pull?

If you've ever over filled a 4 stroke engine at TDC with oil it too is hard to pull start. Also if you ever adjusted the lashes on the exhaust stroke at TDC instead of the combustion stroke at TDC it is also hard to pull start.

These 2 issues are simple to check and fix if need be. They can easily mimic a high compression issue. Therefore, it'd be wise to check these 2 things first before going to a more complex issues dealing with compression.
 
Sidewinder Jerry said:
So are you saying it's no longer hard to pull?

If you've ever over filled a 4 stroke engine at TDC with oil it too is hard to pull start. Also if you ever adjusted the lashes on the exhaust stroke at TDC instead of the combustion stroke at TDC it is also hard to pull start.

These 2 issues are simple to check and fix if need be. They can easily mimic a high compression issue. Therefore, it'd be wise to check these 2 things first before going to a more complex issues dealing with compression.
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I am saying that being hard to pull wasn't/isn't an issue that they asked to have addressed. Aka, a non-issue.
 
It sounds somewhat like an issue when the OP says he has to use a go-kart starter box to crank it because a recoil starter won't work on it. This is why I said to check the oil level and make sure the valves are correctly adjusted. If either or both have issues correcting them may allow a recoil starter to be used.

If there's no issues with either oil levels and/or valve adjustments; then a compression relief valve is needed for a recoil starter or an electric starter needs to be installed. Which the title indicates.
 
Sidewinder Jerry said:
It sounds somewhat like an issue when the OP says he has to use a go-kart starter box to crank it because a recoil starter won't work on it. This is why I said to check the oil level and make sure the valves are correctly adjusted. If either or both have issues correcting them may allow a recoil starter to be used.

If there's no issues with either oil levels and/or valve adjustments; then a compression relief valve is needed for a recoil starter or an electric starter needs to be installed. Which the title indicates.
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I would agree with you, but once again the context and his post don't present it as an issue. It is only in the title of the thread. Until he expressly states it as a problem, it isn't a problem that really.needs solved. I have nothing against your suggestions as they are spot on, so dont take it as such, just questioning the need for the troubleshooting. If it is needed, and it helps, awesome.
 
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