Hi everyone, great board,

Am looking for some help with an '89 Yamaha Champ 100. The poor thing is blowing out smoke like a steamboat and I'm guessing needs a good overhaul. So I'm going to try and fix it myself but need a few pointers to set me off in the right direction.

It blows out smoke from the moment I start it and goes through oil at a high rate, so I am assuming it is burning oil that is causing the smoke. A good assumption, or not?

I've read that a smoking quad normally means pistons rings, valve seals or a damaged cylinder. Anything else I should know about?

I have just bought a manual from Yamaha and am starting to pull the thing apart. What should I look out for as I go? I have also bought new piston rings and a head gasket to try for now.

Thanks for any help in advance, will keep you posted on my success in the coming days.

Fluke.

 

A good friend of mine has a 87 champ that does the same thing, even after having it rebuilt twice. I really beleive that he never had the head looked at and the oil is coming into the cyclinder from the valves. I would start by taking it apart and checking everthing. Then decide if just rings will work or if everthing will be required. (piston, bore job or new cyclinder, and valves) The biggest problem he has had is with the cam chain. I have never had a problem with our Badger, but he cannot keep the cam chain tight enough so that it won't jump time. I believe that his tensioner must either be worn alot or he just doesn't have it in right. So you might want to keep an eye on that. One other thing to watch is the air duct hose coming from the air box. They are known to get hard and not seal on the ends and let dirt get sucked into the engine. Which in turn can break rings and score cyclinder walls, causing it to blow smoke. Alot of guys change them when the rebuild the engine.


Good luck, and welcome to the board. There are alot of good guys in this part of this board that will help out. Just keep postin and shurly someone will help you out!!

 

asfasasu3,

Thanks so much for your reply. I will take into consideration all that you said. Last night I was able to completely strip the head down and inside this is what I found:

The piston itself was very black and caked with what I am guessing is oil residue. I am able to remove some of the deposit but am not sure how I should go about removing it completely. Should I soak it in a solvent to clean it or could I damage it in some way?

The head is also in much the same shape. The valves were caked up with thick deposits of this black "gunk" and so that too needs a good cleaning. Any common methods I should know about for cleaning a head? I have not closely inspected the valves as all I can really see is this black stuff they are caked in. It does appear that the exhaust valve is in much worse a case that the intake valve. I am going to attempt to remove both valves tonight and inspect the valve stem seals.

Finally, the cam chain issue seems to be the same with mine. It appears quite loose, although I am not sure how much tension it requires. I have ordered new exhaust and intake chain guide stoppers, which were totally missing, to see if that will do the trick, as well as a new chain. I will take a look at the tensioner to see if there is anything I can notice with that. Although again my untrained eyes will probably not know what to correctly look for.

Thanks again for all your help and I will keep everyone posted on my success.


Fluke.

PS Am I allowed to post pictures (small in size if necessary) of my discoveries? Just thought I'd ask.

 

Did you figure out your timing chain. mine is loose as well?