Hey guys! I'm at a lost here and have nowhere else to turn, yep that bad!
My friend has a 1986 Moto 4 w/ YFM225S motor that was smoking really bad. I removed the engine and rebuilt the topend. Installed new rings, valves and gaskets.
I know nothing about ATV's and this is the first one I have ever fixed.
After I had put everything back together I tried to start it up but it will not start. If I pump the throttle while turning it over it will backfire out of the carb.
Here is my issue. I have no idea what the valve clearance ought to be so I set it at .002 in. .005 ex. and as far as the timing chain goes where do i line up the "t" mark on the crank? There is no marking on the case.
So I set the crank where the piston was at TDC and lined the cam gear to the long tooth mark on the edge of the case on the head. Could I have set the cam 180 degrees out? If so where should the cams be when it's at full compression? I heard that it would be at 4 and 8 o'clock.
Sorry I do not have a service manual as it took our whole budget just for parts.
Also any help on where the settings on the carb are at and should be.
Thanks for any repies.

 

Well, seems there aren't alot of people on here that deals with the moto 4?
Anyhow, I noticed on the stator case there is a plug on the top. I removed it and saw a line milled into the threads. I figured that this was the case marking fro the timing. I lined it up and my cam sproket was about 2 marks to the left of center. I adjusted it 1 tooth and now it's 1 mark to the right of center! There is no way to get both the crank and the cam exactly centered.
So, I hope this works.

 

OK, I got it running!
My cam was 180 degrees out. The marks lines up perfectly now. Also i had the wrong spark plug. Found an old one in the luggage box and installed it. Fired right up!
All I had to do was adjust the idle.