1979 XS650 Used Cylinder on Ebay

79Dano

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I am rebuilding a 1979 650 Special II. The bike had frozen engine. I have taken apart but broke a piece from cylinder cooling fin so am looking for another on eBay. I noticed some sellers indicating that the cylinder is for a YM159B, or YM252B, or SM254 engine. What are these designations and should I care? I have looked up part number for cylinder on Bike
Bandit and found 2M0-11310-00-00 so as far as I can tell there is on one cylinder used on several engine models. Can anyone verify that?
Also new parts are hard to find so you have to buy used. Does anyone have recommendation on how to approach. I found a big bore piston kit with new pistions, pins, and rings. Should you just plan on boring oversized or pay more for best cylinder you can find and hope you can just hone and reuse your old pistons?
 

DogBunny

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YM159B, or YM252B, or SM254 are inventory numbers used by eBay seller "mistermonkeyclaw", and mean absolutely nothing.
I am not an engine guy, so maybe someone else will chime in and answer your other questions.
Welcome to the Forum.
 

DogBunny

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Also, Bike Bandit is a poor choice for part numbers. The original part number for a 79 Special II cylinder is 306-11310-01-00. The number you found might also work, but it's not original.
A much better parts manual can be found here:
http://biker.net/
Though not as good, for some reason a lot of people like Partzilla:
https://www.partzilla.com/catalog/yamaha/motorcycle
If you go to the tech section at the top of the page you will find more links to manuals and resources.
 

79Dano

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Thanks for the info. I just looked a info on Biker.net. It has great info.

Another question. Where can I get paint code number for 79 Special II (black) so I can get paint mixed up?
 
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