1985 200X is locked up

[Jaymesbf]

My brother-in-law has a 1985 ATC 200X that had the motor rebuilt by a professional. There was a rattle that started at high RPM's and when he called the guy who rebuilt it, he said that it was probably the cam chain. I loosened the adjuster bolt on the left side of the motor just a bit (like my manual instructed me to), tightened it back down, took it for a little ride, revved the engine a bit and it just locked up. The motor seems seized because I can't move the kick start lever at all. I was just wondering if anybody had an idea of what it could be or what to look for before we have to tear it apart or pay for it to be done again. Any thoughts, suggestions or ideas would be greatly appreciated.

[yaegerb]

when you adjusted the chain tension bolt, did you have the bike idling? I have found that the chain tension mechanism won't adjust properly without the motor running. The fact that it seized could be a number of factors that will need to be diagnosed by taking the engine down piece by piece and inspecting. A few items you can quickly check is below:

1. Valve lash, it should be set at .003 inches.
2. Drain the oil...do you see large metal flakes in it? If so, a bearing could have gone out on the crankshaft, case, etc.
3. Check your kickstarter gears, I have seen "professionals" put these in incorrectly many times.
4. Check to see if the cam chain broke. this can be done by removing the cdi cover and pulser plate.

Lastly, I would take the engine back to whoever built it and have them look at it and fix if any of the above don't pan out for you.

[Jaymesbf]

The motor was idling, like the manual said. The first thing I did was check the cam chain, it's fine. The 2nd was draining the oil, it was dark but no metal flakes. The kick starter just seems unlikely because it worked for the year after the rebuild, previous to the adjustment and stopped working 5 minutes after the adjustment. Is it possible to have the chain fall off of the crank?

[yaegerb]

Yes that is possible, but unless it broke and wadded up next to the crankshaft I highly doubt that's your issue because you can't kick the motor over. So, with those items eliminated, have you checked your valves? If not the valves then I would say you could possibly have a seized bearing. That rattle may not have been a cam chain but a crank bearing.

[Jaymesbf]

The rattle only came at higher RPM's and I'm not positive, but it seems like all internal bearings were replaced. The valves have not been checked, though.

[yaegerb]

After you adjusted the cam chain and revved it up, did you still hear the rattle?

[Jaymesbf]

It locked up before it before there was even a chance to hear it.

[Jaymesbf]

It idled for a while after the adjustment and rode well for a few minutes at low RPM's. As soon as we gave it some gas it locked up.

[yaegerb]

Sounds like its time to rip into the motor

[Jaymesbf]

That's what I was afraid of. I appreciate the help and somebody else's opinion. Thank you.

[CodyRosa]

I bet cam chain broke? Or if it fell off it could have bunched up in the bottom on the crank. I've dropped my cam chain down there and i can not budge my crank shaft. Hopefully all is good or at the least minor damage. I'd just pop that top end off and check it out.

[Jaymesbf]

Cody, did you read all of the replies from yaegerb in this post or just what I wrote when I initially posted this? If you haven't read all of this thread, please do and let me know if you still think the chain is a possibility. I agree with yaegerb that it seems unlikely because it makes sense that the only way for it to bunch up is if the chain is broken, and it's definitely not. The motor isn't removed from the trike. Just trying to get an idea of what all the possibilities are before it is pulled. Fairly new to this kind of stuff.

[shortline10]

I hope the "Professional" didn't use and silicone when assembling the motor !

[Jaymesbf]

People can stop using quotes for "professional." He owns a very successful shop and is the only worker there. There's not a doubt in my mind that he did everything correctly because it ran like a champ until I made an adjustment. I can tolerate my knowledge being questioned. But I know for a fact that he knows what he's doing. If it was just some random buddy of mine, I'd say some random buddy. I called this person a professional because he is indeed a professional.

[Jaymesbf]

And I know he didn't use silicone because I asked him about using it and he advised me against it.