obsolete pistons for XJ

[Luca Baldesi]

Dears xj,

Zanotti motors is communicating me the sad new that all pistons for the XJ are not available.........only a few rings

Here are my questions:

- Are the piston of the xs the same for the XJ, can I install xs pistons on my xj?

-Any body has any idea of what is their price (1st o/s with rings)

- In which dealer are still available ?


A bravo ! for the kind answer !

[Jerry]

- Are the piston of the xs the same for the XJ, can I install xs pistons on my xj?

As far as I know, the XS and XJ pistons are interchangeable. Couple notes, though. Early XS engines ran higher compression than later XS and XJ engines. I believe the early compression was 9.5 to 1, later units used 9.0 to 1. FWIW, there was also a change in valve size; later egines used slightly larger valves. If you find the early pistons, a task that may take some doing, you should check to make sure there is no interference between them and the XJ valve train. Have not heard of any, but never hurts to check.

[sixtysix]

I think the XS pistons are discontinued as well, but you can buy a 'big bore' kit from Wisco. The 1179 and 1196 kits are still available.

Check out the following threads for info.oversize Pistons?

Big Bore Kit?

they only list the XS...not XJ so you still need to know if they are the same.

[CA.XSer]

Check this site for part numbers between the XS and XJ.

http://63.164.134.66


Then go to parts and service, then parts catalog.

[Jerry]

My XJ microfiche lists the piston part numbers as 3H5-11631-00-46. This means the pistons used since the '80G are the same; Yamaha uses the first 3 characters to note where the parts were introduced. I suspect earlier pistons will fit, as well as the Wiseco, but may have a different compression ratio than stock.

Note that for the XJ the first 3 characters for parts is 10M. Parts with this designation were first used on the XJ, and are often unique to it. In some cases the diferences may be cosmetic, but most ofren they are mecahnical differences that don't allow swapping for parts between the XS models and the XJ bikes.

If a part number starts with a series of numbers, no letter characters, it means the parts (bolts, washers and such) are pretty standard parts and not unique to any one bike.