84 ATC-110 not starting? Ideas??

[moreschi88]

Alright here's the run-down. We were running fine. I mistakenly put an ATC-125M spark-plug in the unit. The plug was about a 1/4" longer and there was just the smallest nick on the thread from a possible piston/valve altercation (anyone know which one it would contact). I've put the proper spark plug in since and it's not wanting to fire up.

My compression is 110 PSI and leak down is at 80%..
I am not sure what a "leak-down" is, but the ATV shop manager seemed to think that 80% leak-down meant the electrical components are working fine so I imagine the stator-coil and misc. electrical parts must be good. Electrical was my first thought....

Could there be a lingering piston/valve issue from using the wrong plug?

Any advice on this is greatly appreciated. Thanks

[Mr_RPM]

leakdown has nothing to do with electrical. the compression should be anywhere from 156-198PSI. if it was running fine before the too long of a plug and now it wont run then it looks like you made some bad damage and its time to tear it down. when he made the leak down test did you hear where the air was leaking from? exhaust?, carb? dipstick?
running the 125m spark plug wont effect the electrical.
that low of compression is a big sign of bad engine damage. tear it apart and see what is broke. good luck

[moreschi88]

I felt kind a like an idiot after some quick online leak down research after the post.

I wasn't at the shop when they did the leak-down test and they didn't fill me in on where the leak might be focused. At 80% I imagine there may have been a few locations of concern.
We'll just have to get into it. It's a long overdue re-build on the front-end for this trike anyway.

Thanks for the good luck wishes b/c I have never done this type of pull-apart on an engine before. On Saturday I got to the point where I was working to pull out the cam-shaft and I couldn't find the bolt to loosen the sprocket chain and it became difficult so I stopped there. I'll have to get back to it tonight and see what I find.

[Mr_RPM]

do u have a manual? contact monroemike (something like that) and he will hook you up with a few manuals. theres also a few manuals you can find on this site. actually i find something for you. ill PM you.
it will be your best friend with a build. also take advantage of this site and feel free to ask questions and look at past posts. GOOD LUCK!!!!