I'm going to do the top end on my 1986 TRX125. I wanted to see ballpark prices on parts before heading to the dealership, and they call out parts for two different pistons: Riken and Teikoku. There are two of every thing from the pistons to the rings in standard and all the oversizes.

There are no engine serial numbers by the parts indicating which one is used where, so does this mean I can use either one interchangably?

I have my piston out of the machine, but I don't see any markings that would indicate it is one of these specifically. I'm worried about getting the right parts ordered and installed.

Is there even a difference in the two?

For reference, I was looking at bikebandit's OEM parts list.

 

The parts are machined the same .. There are several Honda models like this .. Are you having the engine bored to the next oversize..?

 

Thanks for the info. I was worried about getting the right parts.

I was just checking my parts and it really doesn't look like they are too worn. I wasn't using a micrometer, but was using a digital caliper. The piston is still within spec, and the bore appears to be right on also. No scoring is present, so I'm hoping to just hone the cylinder to brake the glaze and install new standard rings.

So your probably wondering why I even pulled it apart. This was a freebie 4-wheeler from a friend. It had been sitting for about 4 years before I got it a few months ago. I got all the other mechanical issue with the thing fixed and got it running. However, once it warms up a bit, it really starts smoking pretty bad (oil smoke). I thought it may just need to be cleaned out a bit (run hard) but this didn't make much difference. In fact, the smoke gets heavier as it warms up more. Compression when hot was 125 psi, which is a little low, but I just wasn't happy with the amount of smoke this thing was putting out.

By re-ringing it, I'm hoping to cure the smoking problem.