Pro-x Vertex or Wiseco?????

[Rattlesnake_06]

Its time for a top end and this is my first ktm. Its a 01 250sx and has a Vertex piston and ring in it now and was just wandering which is the better piston kit. I have always ran Wiseco in every other bike ive had and would assume to put a wiseco back in it but wanted to know what piston other ktm riders are using and why. Thanks alot guys!!

[tye1138]

Vertex is OEM, so I'd just pick one of those up.

[rpt50]

I've run wiseco in every bike I've owned, so that's what went in my KTM 250 sx. I don't know why, but KTM guys (far more than any other brand) seem to really have hard-core opinions about pistons, and definitely favor the OEM style, but the basis on which they make this choice never seems clear to me. Of course none of us has ever done a controlled experiment comparing different piston types, and even if we did, the results would only be applicable to our own conditions. In a recent issue MXA had a good write up on the pros and cons of forged vs. cast and other piston types if you want to do some reading.

Edited January 1, 2012 by rpt50

[Rattlesnake_06]

Cool guys, thanks alot!!! Ill go with oem and see how it goes. Guess if KTM likes em they must be atleast useable. Ordering parts now, got a pile of em comin!!!! Thanks again.

[wheels2]

Make sure you measure the bore of the cylinder. Vertex comes in #1 and#2. Chances are good you will need a #2, but you should check to be sure.Have your local shop measure for you if you're not sure how to do it.

[hardhitwarrior]

just read whats on the piston what size. then order thesame or 1 size bigger.

[rpt50]

Be aware that if you go with OEM, the clips are seriously gnarly. You might want to invest in the bux piston clip installation tool. I have not used it, but it is widely recommended on the KTMtalk website.

[maxamillion125]

Always buy the #2 or B size piston, unless the cylinder is brand new. Vertex and Wiseco are your best bets. Learn the difference between forged vs cast piston if you decide on Wiseco. (mainly just let it warm up thoroughly) No need to measure, you can inspect the cylinder visually to look for cross hatching, vertical lines and feel for scratches. The exhaust port is almost always the first place you will find the nickel platting starting to wear off.

[Rattlesnake_06]

I have no cross hatch at all. And the plating looks really good. Its shiney like a mirror. Should it have cross hatch?

[maxamillion125]

Normally you can still see cross hatching, but it doesn't mean its bad if there's none. Can you feel any scratches anywhere or chips. Sounds like you'll be just fine.

[wheels2]

Look real carefully around the ports and see if the plating looks like it's worn off.If it is, and you put a new piston and rings in it, it could have ugly results.A nice new ring could catch the edge of it and start flaking off the plating.Just inspect the cylinder closely and save yourself money and aggravation.You'll be happy you did in the long run!

[Rattlesnake_06]

I can see a little spot just above the exhaust port. It doesnt look chipped or anything. Just kinda worn. Can i hone it?

[wheels2]

Use a scotch bright pad and try to clean it up. Then take a better look at what you've got.

[Thueske]

Always buy the #2 or B size piston, unless the cylinder is brand new. Vertex and Wiseco are your best bets. Learn the difference between forged vs cast piston if you decide on Wiseco. (mainly just let it warm up thoroughly) No need to measure, you can inspect the cylinder visually to look for cross hatching, vertical lines and feel for scratches. The exhaust port is almost always the first place you will find the nickel platting starting to wear off.

I have a question: you say no need to measure, but when I look at the Vertex cataloque there is choice between 4 size's of pistons. How can you make the right choice if you don't measure?

[hardhitwarrior]

iv said this again. go with what ever size the previous piston is in it (be it OEM piston or AftMmark.). or take 1 size bigger.

if it cylinder an A and now its used/worn, then id suggest a B or C.

[Rattlesnake_06]

mine says 66.35 on top of the piston

[maxamillion125]

I have a question: you say no need to measure, but when I look at the Vertex cataloque there is choice between 4 size's of pistons. How can you make the right choice if you don't measure?

I wasn't aware that your bike had 4 different vertex pistons available. To my knowledge most have only the "A" and "B". Either put the same piston you had in it or go one size larger. You can measure if you want but I never have. I've always been able to judge the condition of my cylinder without using any measuring tools.

[hardhitwarrior]

mine says 66.35 on top of the piston

are you sure its 66.35 not a 66.340? yes with zero. the original KTM piston from factory on mine came with 66.340. making it an A size 66.34mm piston.

[Rattlesnake_06]

Ya it says 66.35.

[Rattlesnake_06]

Wish i could figure out how to put pics on here ?