Hi guys, kinda new to the forum, I have an 85 ATC 250R that I bought a few months ago, Im a mechanic by trade, but have never really been into the 250R engine before, so this may sound dumb, but im trying to figure out what I need to know.

I have a loud rattling noise coming from under the stator cover, and I was told it could be the counterbalancer bearing or holder going bad, and I was looking for some suggestions on what else I should look for, and ideas on how to fix it, I ordered a Clymer manual, but its not here yet, so im just trying to ask all of the right questions from people that would know the answers I am looking for.

The noise is pretty loud, you can hear it over the engine at idle, at higher RPMs I cant tell if the sound goes away or is drowned out by the engine. The best way I can describe the sound is, that it sounds like the ratchet mechanism on the kicker when it is down while the engine is running. And if you place your hand on the stator cover you can feel it as well. The motor runs great, no vibrations, no misfire, no other complaints about it other than the rattle. I dont really feel like riding it until it is fixed, I am usually not happy until the engine is running 100% then I can relax and ride like I should.

1. If this is the CS bearing or holder, this a job I can do myself? (i.e. special tools required?)

I have a full shop at my disposal so basic tools are covered.

2. Anything else I should look for or replace while I am in there?

3. Parts: OEM or Aftermarket? (as long as Aftermarket is an improvement over OEM)

4. Any little tricks you might know that will help me get it apart. (step by step instructions would be
great!)

I figured this would be a good place to post this question (250R quad guys)
(Moderator: If this subject is inappropriate for this forum please feel free to move it)
Thank you for your time. HH

 

I wouldn't ride it like that, more severe damage is likely. Pull the stator cover off and look for loose/broken bolts at the counterbalancer plate, it's somewhat behind the flywheel in front of the crank. You would be wise once you get the service manual to pull this engine completely apart, inspect it and replace whatever is in question that way you will know it will be reliable when you go to ride it. This is a great engine but things do wear out eventually and with it's age an overhaul would be a good investment. The balancer comes out of the engine from the right side (clutch) it is timed to the crank by marks on the gears. They can be rebuilt if the shaft is not damaged.