Wiseco piston install on a atc 200

[86trizinger]

I just put my ATC 200 engine together yesterday. I adjusted the valves to specs. When I try and pull start it,, the valves seem to tap the top of the piston.. Its a 10.25 piston. Please any help would be great. I made sure the valve size corresponds to the intake and exhaust side. The arrow on the piston faces the exhaust.

Thanks

[oldskool83]

timing off then.

[86trizinger]

Just double checked. Timing marks are dead on. I appears to be the intake valve.

[fabiodriven]

You could be 180 degrees off.

I hope you didn't turn it over as if you were trying to start it. Hopefully you turned it over nice and slow when you found out there was an issue. If you did turn it over and "tapped" the valve off of the head, you very well could have bent the valve.

[shortline10]

if your using a stock cam it shouldnt hit as long as the timing is set correct .

[86trizinger]

I am going down to look at it right now again. I did it the same was as my 200x and it was perfectly fine.

[86trizinger]

Alright. Checked everything again.

T mark lines up with cam.. Both valves are completely shut at that point. So that should mean that I am not 180 deg off. When I install the CDI pickup it lines up perfectly when the manual says. I turn it over slowly and I think its when the valve is shutting. Should I pull it apart at this point?

[86trizinger]

Pulled the engine back apart. No mark on head, cylinder or valves. With the head off the noise is gone. Is it possible the decompression lever is messed up. I noticed on the rocker arm there is a mark worn into it where its been hitting for a while. I am wondering if the exhaust valve was slightly open.. because the engine seemed easier to crank than the original engine.


Any suggestions would be great.

[fabiodriven]

I wish I could help you more but I gotta say, you sound like you may be on to something with the compression release...

[oldskool83]

i agree on the compression release. i guess take pics so we can see.

[86trizinger]

Put it back together.. Played with the compression release a little. Definitely has more compression now and alittle less noise. I will swap my levers around and see if that helps the noise.

[86trizinger]

I switched decompression levers from my other engine. Problem went away totally now. Very hard to pull start now. It about ripped my should out of the socket when it caught.

[fabiodriven]

Well at least you know what the problem is. Good job.