200cc clone losing power

[Poboy kartman]

My bad- when you said hand /manually/ whatever. ...I was thinking you meant at the engine.....carry on..... .....wish I could help. ...

 

[OzFab]

I just ran it wide open with a new plug for 1/2 hour and the plug remained perfectly clean, is this a sign it is running lean?

That depends, were you riding it or was it sitting still? A mixture check needs to be done under full load...

 

[mark123]

Riding

 

[Poboy kartman]

Dadgummit- it's things like these that just make me wish I could put "eyes on" the problem. .....

Oh- that reminds me- please fill out your profile so we know where you are from. Help could be next door. ....

 

[mark123]

OK, I just received my new Honda 18lb valve springs (G200 part) and installed them and nothing, no improvement at all, I can't describe how frustrating this is. One thing I noticed is that with the valve cover off the exhaust valve operated twice as fast as the intake while I am turning the engine over with the electric start, I assume this is supposed to happen with the decompression system built into the exhaust cam. Is there a chance the mechanism is malfunctioning and this decompression thing is not releasing at higher rpm like it should. Mechanically the engine is perfect, I moved the exhaust rocker arm off to the side to check compression and it is 155psi and there is less than 4% leak down. Tried with exhaust removed, air cleaner removed. I even tried running wide open and dripping extra fuel into the intake and it just stalls.

 

[happy_8637]

I moved the exhaust rocker arm off to the side to check compression and it is 155psi and there is less than 4% leak down.

thats awesome...

 

[mark123]

I got it all apart and think I found the problem, as I said before the exhaust valve's stroke looked much less than the intake valve's. I took the cam out and here are the measurements. The intake lobe's narrowest is 0.867" and the peak of the lobe is 1.088" the exhaust's narrowest is 0.867" as well but it's peak is only 0.943" . I read that the stock rocker arms are 1:1 ratio so the intake has 0.221" lift and the exhaust only has 0.076" of lift. The edges of the exhaust cam definitely look worn. Would this have happened due to me installing 0.100" shims under stock springs or just poor quality materials, like I said maybe 10 hours on this new engine and always ran 100% synthetic 10W30. My stock springs are approx 1" long and the new 18lb G200 springs are approx 1.5" tall. The flywheel was spot on and tight, key in perfect shape so ignition timing was not the problem.