Which Piston to use.

[Sure Shot]

well it's almost time to rebuild my 220 and after hearing about Kyles misfortune (Sorry to hear about that Kyle good thing you work at a shop and have someone who can give you a hand.) I don't think I will be using a stock oem piston. I know that weisco is a good choice but I have heard some negitive comments about fit and I have heard some mention of Pro-X pistons which I have never heard of before. Can any you guy's give me a heads up on which is better to use, I know I can get a kit from weisco does pro-x have the same set up. Any input would be much appreciated.

 

[Fred T]

Just get a WISECO, you'll be fine. The key is to break the bike in properly and let it warm up before you ride it. Just common sense stuff.

 

[Robcolo]

AND-----search for Sage's post on the Weisco circlip problem. The wrist pin was just a few 'thou too long on some Weiscos and it prevented the circlip from fully seating. When these circlips worked loose it was just as bad as the skirts coming off. Just check & make sure that the clip is fully seated.
Another hint: The oem piston has the wrist pin hole chamfered whereas the Weisco doesn't and it's a real sob to just get the circlip into the hole. Chamfer that hole before you install the piston.

 

[toalco-kdx]

what are the benefits of not using oem pistons, like the wiseco or pro-x? more power?
thanks.

 

[Fred T]

OEM 220 pistons crack.

 

[fatty_k]

I dont think you will notice a power difference any more than what it would be with a fresh top end anyways. BTW, my cases are going to be split on tuesday, the mechanic thinks it might just need to be welded up and put back together. So I dont think it will be that bad.

 

[canyncarvr]

For whatever reason (or none at all), the Pro-X site lists the multiple alpha designations of pistons (steps of .01mm/.0004") for the 200, but NOT the 220. So, to the extent the intention is pro-x or wiseco for the 220....you dont have a choice.

In any case, that's a good thing, as the pistons from pro-x are the same as what's in the kdx in the first place. At least for the 200. Don't know that it's a safe assumption that the oem for the two bikes is the same.

The following is from the pro-x website for a '00 220. They don't even list a piston, period!

PROX partnumbers :
Piston kit*: Piston ring set*: Piston pin: Circlips:
       
Connecting rod kit**: Pist.pin needle bearing Big end pin: Big end cage:
 03.4285  .................21.4204  ....................06.2251  .......22.222917

I asked 'em why a week or so ago. Never got a reply.

 

[dtsviper]

Well, I just learned yesterday that Pro-X is in fact the same thing as OEM. They are the same piston as what you buy from Kawasaki, just sold under the Pro-X name.

With that being the case, I went with a Wiseco in my 2000 KX-250. I think I also have a Wiseco in my '98 KDX-200?!?!?!?!!?!?!

As for Wiseco, just don't start it up like a motocrosser, i.e., let the thing warm up a little before you get on the throttle! It definitely needs some warm up time to let everything settle in and expand as the Wiseco piston expands at a different rate, i.e. faster than the jug.

I have never seized a Wiseco piston, but then again, I always let the bike warm up before I start twisting the go-grip!

Hope this helps.

David