110cc Engine Slamming, wont start
 

Hello! I am new to rebuilding ATV's and I'm on my third one with these Chinese 110cc's with my kids. I have a current one that is stumping me if anyone can help....

I bought one from a guy who says the Stator caught fire, and then he disassembled it. I bought it with the engine emptied of oil and sitting in a bucket (inside).

I have since tore it apart, cleaned it out, all new gaskets, and then put it back together making sure timing was correct.

I assembled the ATV with new battery, new stator, all new wiring, new starter, new spark plug, new oil, new carb, new gas tank.

When I go to start the engine, I get spark and it turns over, but there is a loud slam from the engine (sounds like metal grinding maybe?) and the engine kicks once, then goes back to just turning over. Every time I press the starter it does this kick/slam/grinding once and then keeps turning over.

I can't find anything online helpful, and since I don't have a lot of engine experience I'm not sure what to think or what to do next. Can anyone offer some advice?

It’s pretty hard to diagnose any sound going by someone’s written description ,you might want to make a YouTube video of the problems .

Good point, here's a video:

https://www.youtube.com/watch?v=KbOAhFHPIhY

Transmission or clutch assembly error?

I saw that chain kick when it stalled.

I mean, you can crank it, without the wheels turning, but once it starts to turn a real RPM, it looks like the chain is engaging for a split second. That’s definitely down to transmission or clutch in my opinion. Probably clutch.

Hmm, I only took off the covers and then replaced them when I took apart the engine. Could I have done something wrong without actually taking the transmission/clutch apart?

Well, it did come used in a bucket, so who knows what may have happened to it previously.

As a matter of fact, looking at the video one more time, I see the chain moving even when you crank it. Is it definitely in neutral while you are starting it? If so, something is engaging it.

It’s definitely not free turning. There is certainly some problem there after the engine in the transmission or centrifugal clutch area.

I'm not sure about the neutral factor as there is no shifter or anything. So what would that mean?

I’m sure you already tried raising the rear wheels off the ground and with a fresh charged battery try again? This would determine if there was at least a clutch malfunction?:hmm:

This battery is new and was on a charger before this, also starter is working and I'm getting spark.

I have not tried with the wheels up actually. Would that make it start though if it were a clutch issue?

That may define the difference. If it starts with the wheels in the air…clutch. If not back to engine…my thoughts as I noticed the chain jerk too!

I elevated the wheels, new video:

https://youtu.be/sqvwQL5nvco

It’s looking like to me the clutch system may be the problem. The starter can’t spin fast enough to start trying to turn the wheels too?

Another thought, take the chain off and try to start again. This too will give you the clue where the problem lies.

So regardless it sounds like I'll have to open the engine back up? What do I look for in the engine/clutch?

What we do is eliminate the easy things first then go from there! If with the chain off and it wouldn’t start, then engine and clutch. I don’t know your engine, just pointing too the problem.:tup: