View Full Version : RD to RZ PISTONS?? HELP

2nd May 2006, 12:20
I am in the process of doing a top end rebuild of my 1984 rz250 (29L) YPVS. So far the cheapest pistons I can track down are aftermarket rd250lc pistons. Apparently the boost ports on these are smaller and skirt longer than the RZ ones. Has ANYONE modified the rd pistons to suit an rz??? Can it be done? Any help would be great, otherwise its off to Waikato Yamaha for some OEM (expensive!) action... grr

F5 Dave
2nd May 2006, 17:11
So presumably you have done a websearch? Wiseco arenít too expensive, but ProX do RZ ones, think thatís what I used for my RZ350. Yam pistons are usually ART brand & ProX is ART backdoor sales.

As far as the mod of using RD ones best you check the RD forums (erm can't remember, google it), but chances are the dome shape may be different or if you are unlucky the small end bearing may be a different size (or width which can be hard to pick), or the gungeon to crown distance may be different or the ring pegs may be in ports, but the RD-RZ are pretty much the same sort of layout.

Iíve done a few piston swaps but sometimes there is a lot of work. Sometimes it is real easy.

3rd May 2006, 21:47
For 350LCs we have to use YPVS pistons, as no one lists LC piston kits as a separate item. Drop in except you need to file the tang off the skirt in case it catches in the boost port. Some people don't do it (like the previous owner of one of mine) but they get away with it... mostly.
Have you tried Tony B - (motoequip) - I got some TKRJ piston kits from him and they were good value.
Anyway, shoudln't be a problem - gudgeon, deck height, bore are the same from the LC on - not sure about the air cooled ones but I think so.
Alec's RD forum http://www.yamaha-rd.com/forum/ will have a definitive answer.