No, it hydro locked with the bad carb. Changed the oil, switched carbs. Still won't start. Switched plugs, too. Still won't start.

 

Thanks, Dirt. That is a very good video, but he didn't show how to tell that you are at TDC on the compression stroke. I did that a while back, but wasn't sure my TDC was on the compression stroke. I've since learned that I should take the plug out and put my thumb over the hole while having my buddy turn the engine by hand. When you feel air pressing on your thumb, tell your buddy to look for the T in that little hole to line up with the mark.

 

I thought the video mentioned the TDC mark was under the side case? No matter, as long as you get there all is good!

 

Well, I was able to test the compression...within spec. I also tried adjusting the valve lash and had some issues with the exhaust valve I discussed in this thread: https://atvconnection.com/forums/yam...iak-400-a.html

 

UPDATE!! Took the quad to a cycle shop and told the guy that something was wrong with the timing, and that TDC did not yield loose arm in the exhaust valve...but he insisted on cleaning the carb and adjusting the valve lash. He put it all back together, and BANG big back fire! He then explored the timing, and found that the starter had sheared the flywheel key pin when the engine was liquid locked. $466 later, and it’s running again.

 

That sucks...in reply #4 I mentioned timing, however it is very rare that timing is the issue and is often overlooked...but that did describe your difficulty in finding TDC with the timing mark and why it wouldn't start...sorry we couldn't get this resolved via message board...I hate bringing my stuff in and haven't done so for a LONG time...

 

Yeah, I wouldn't have been able to do this work myself, because it required a special puller, etc. I just wish he would have listened to me and trusted that I had done a pretty good job of testing it.

 

but that would mean less billable time...:P

 

As a quad mechanic I learnt long ago not to take much notice of what the owner tells you. Take this scenario, owner comes in with non running bike. "It ran out of fuel in the field, I put it on reserve, but it still wouldn't start" he says. So you check fuel is getting to the carb, clean the carb out, find nothing and it still won't start. You then ignore what the owner said and check for a spark, find none, which is the first thing you check normally, so the carb removal and cleaning was a waste of your time and their money.

 

Interesting perspective...