Yamaha xs360 Ebay Pistons and rings

[Normand]

Hey there, i have few questions!

Would you trust those pistons for a rebuild?

http://www.ebay.com/itm/Yamaha-XS-3...ash=item41ba01b9fc:g:bacAAOSw241YU~Vk&vxp=mtr

It look like 0,75 oversised.

What about the numer 1 on the top of it?

I have never change any piston before.

Here is the link of my other thread asking if i really need to replace them
http://www.xs400.com/threads/pistons-or-rings-or-both-replacement.16372/

Thanks!

 

[BBS360]

That's an arrow that points to the front of the motor during install.

If I had the spare cash right now I'd probably buy both sets.

 

[NewHavenMike]

I purchased the same kits for my 360 on EBay. They were .25 OS pistons though. I forget how much the two kits cost, but it was more than that listing and the seller was in the USA.

Verfiy that the cylinders on your bike are good to be machined to .75 over.. You need to have the pistons when you bring the cylinders to be machined to ensure they are within the tolerance spec, which is .002 I believe. even though my machinist said it was OK at .003... The engine started right up and sounds great.

Be VERY careful with the piston rings. I snapped one when it landed in the wrong groove and I had to remove it. I did the rings by hand though. Having the ring tool is pretty much essential.

The piston rings are also directional so they need to be installed top side up. Which is indicated by very small markings on one side of each ring.