XS 400 PISTONS IN XJ 900 N 1985

Hello Chaps,

Well after a 2 weeks of searching and finding the XJ 900 N price for rings is now $105 RRP per piston, I have tried Germany, Japan direct everyware . I was thinking that is just a bit steep considering I can buy new piston and rings for that price.

I have done lots of testing and numerous measurements and with my compression just a tad low and the bores needing honing I think I will go the new piston modification option. I might bore it out and throw in a set of XS 400 1979 pistons. They are 69.25mm 1st oversize - mine are 68.5mm. Question - not sure if the piston rod is the same. Does anyone have any ideas or thrown any other pistons in their XJ 900. I am a DIY guy if you have any suggestion please reply. I would prefer new pistons and rings based on testing.....

 

I don't know about the wrist pin, but I can think of a few things you should also consider:

1) Piston weight. I believe it has to be the same or the counterweights on the crank will need to be modified.

2) Piston skirt length. Not good if the crank hits the piston skirt.

3) Piston crown height. If the height isn't right the compression will be off or it can strike the head/valves.