Are Pro X pistons forged??

Are Pro X pistons forged?? Are they better than wiseco??

Are Pro X pistons forged?? Are they better than wiseco??

They are cast same as OEM, and no IMO

Pro-X pistons are cast they are actually made by ART who makes most of the oem pistons for yam,hon,kaw,suz.

No , they are cast ( like OEM )

My real probl with Weisco is they come in a one size fits all. Plus they alter your comp ratio some.

Pro x / oem/ vertex come in A , B, C to fit your bore properly.

I have used many vertex in our 65sx , and more Pro x in the yz 85 dirttracking bikes.

What about a company called Namura? anyone heard of them? they claim to make a coated aluminum piston

No , they are cast ( like OEM )

My real probl with Weisco is they come in a one size fits all. Plus they alter your comp ratio some.

Pro x / oem/ vertex come in A , B, C to fit your bore properly.

I have used many vertex in our 65sx , and more Pro x in the yz 85 dirttracking bikes.

if ur replating ur cylinder, this wont be a problem.

good point ,, BUT think how many times you get a cyld re plated vs how many piston/top ends you put thru a bike.

i am not replating my cylinder, i rang the guy at pro x and he said they have no "B" instock but thinks i should go an "A" for a cast piston or a "C" in a forged piston.

My bore says i need a B and i can still see the cross stuff in the bore

Try oemcycle. I got a Pro-X for my bike there cheap.

I've had great luck with Pro-X and Vertex.

No , they are cast ( like OEM )

My real probl with Weisco is they come in a one size fits all. Plus they alter your comp ratio some.

Pro x / oem/ vertex come in A , B, C to fit your bore properly.

I have used many vertex in our 65sx , and more Pro x in the yz 85 dirttracking bikes.

You should study the real sizing on the pistons before worrying about the a-d thing. I hate posting links to past conversations, but this one was one of my favorites. Many opinions and several experts offering facts on piston sizing.

http://www.thumpertalk.com/forum/showthread.php?t=468672&highlight=

ya the difference is like .0005" between them all, and its sad to say but really you pretty much need a CMM machine to measure that close, your mics and veriniers may say they do but the variables are way to big to acutally measure something that precise.

Thanks RC , i did read pages 1-9 of the old post . Then i admit i tuned out.

Note : I'm just a backyard dad wrenching on my sons dirttrack race bikes and do allot of the maint , in hopes of seeing our engine builder guy only 1 time a year ( $$$ )

I do reccomend prox or vertex allot because , thats what our engine builder installs and that what i use for periodic top ends the bike needs thoughout our racing season. I replace same with same , do it on time and so far NO catastrofic failures on the 65sx and yz85. Thats my plan and that makes for only one trip to the engine guy a year. So i have allot of good exp with those brands of pistons.

But now i'm kinda 2 faced about this piston who is best deal.

Those bikes are gone, and he's riding a yz125.

His 125mod yz , it is specificly built to run a Weisco GP piston in the mod cyld and mod head. Not crazey about that BUT never the less its our #1 engine combo .

Last year we had a piston pin bearing implode ( my fault , the bike was new to us and i left the top end in racing service tooo long ) resulting in allot of dented massaged parts.

We have been running a mismatched cyld,head,piston combo untill i get the funds to get our engine back to its original form. Surprisingly it runs ok , and he's doing / placing ok with it . Don't ask me how , with 2/3rd of the power he had........ maybe he is trying harder with what he has , i dunno. But we are used to engines that run exceptional , not just ok.

Back to Weisco , before You completly tune out !!! ..

I have gotten a well worn stock clyd reworked / ported ,, and sent the ported cyld AND the new WeiscoGP piston to get re-plated . I learned its best to send the re plater a new piston of your liking so they can size/fit everything exactly.

So with any luck our engine will be in its original form soon.

I kneel and pray ........because funds are tight. no room for stuck ring / cold seiz , non of that shait. Its gotta run.

thanks for listing to my saga , 24hrparkey

I know those long threads are well, long..and I dont blame a person for tuning out. Thats why I hate posting links to them. But sometimes it the only way we can stop the mis-information. Sometimes its not mis-info, but the information is 70's old. I could care less what piston a person chooses, but I do like good info for informed choices.

Later on in the thread someone from wiseco stepped in with facts and figures. He was able to show, in real numbers, the sizing of the Wiseco Pistons vs OEM. The forged piston fits tighter.

I think the companies are playing to us older folk with the minute differences in piston sizes. Way back when we also had the 4 sizes available, and you had better get the right one as the size difference was huge.

One of the highlights related to sizing posted was this:

""For example on my own KX250 the factory clearance is .0023-.0031 or .059mm-.079mm.This is 8 tenths range (almost 1 thousandth). you will always be in that range with brand "W". It is the best practice to measure the piston to cylinder clearance no matter how good the cylinder looks to the naked eye. This also confirms you have the correct size piston and any problem down the road you could eliminate a clearance issue as this measurement is on record.""""

Now, unless my Math skills are slipping (a strong possibility) , once the sizing gets to .001, the only way a .004 difference will matter is with a cylinder so worn other action needs to be taken.

Yeah there is some crazy mis information to be had !! Esp when people have piston failures with brand X ,, i mean you /we do not know the condition of the engine it was put in . Heck they probl don't know either !

Thanks for reading my piston drama .....( PS> NEVER believe the prev owner saying Yeah that top end has about 5 races on it ) ..... And may each riders mechanic choose the piston brand of their dreams.

Ohh well that episode did prompt me to finnaly get an Hour Meter .......

sparkey

Yeah there is some crazy mis information to be had !! Esp when people have piston failures with brand X ,, i mean you /we do not know the condition of the engine it was put in . Heck they probl don't know either !

Thanks for reading my piston drama .....( PS> NEVER believe the prev owner saying Yeah that top end has about 5 races on it ) ..... And may each riders mechanic choose the piston brand of their dreams.

Ohh well that episode did prompt me to finnaly get an Hour Meter .......

sparkey

Thats funny, but I think we figured out ALL used dirt bikes just had a new piston put in. There are a lot of sellers who would feel bad sticking a new owner with worn out parts.

Later on in the thread someone from wiseco stepped in with facts and figures. He was able to show, in real numbers, the sizing of the Wiseco Pistons vs OEM. The forged piston fits tighter.

There's no fancy math to measure a piston, cast or forged. If the Wiseco fits tighter, then it's a larger piston. This won't make up for the lack of A,B,C,D sizing (not that it matters for most people).

If, in fact, the Wiseco has a speced out clearance of .0015" on a new cylinder (compared to Yamaha's recommended .0018"), then it is essentially a "C" sized piston. This means instead of staying within Yamaha's .0018-.0020" spec for clearance, you now will cover a range of .0015-.0021". Is this a problem? Not really, especially when you figure Yamaha's service limit spec is .0040". I just wanted to state that there's no magic to a Wiseco that makes it a tighter fit than any other piston.

I've used both Pro X and Wiseco. The only "advantage" I see with using a Wiseco is that it is better at surviving out-of-spec running, whether its from running WAY too many hours between rebuilds, or because Joe-Shmoe doesn't measure anything when rebuilding (or wants just one more top end before getting that replate). Put a cast piston in a loose bore and you'll be picking pieces of skirt out of the lower end. Do it on a cast piston and you'll just beat on everything. In a proper engine build either will survive quite well.

My last ProX piston when in with .0035" clearance. I was one of those "one more top end before replating" kind of guys. At 50 hrs, 22 min it blew 247 psi on the compression gauge. I then tore it down, and the intake skirt litterally broke off when I set the piston on the work bench. Close one! This time the bike went together with a replate honed to size for a new Wiseco piston. I went Wiseco for two reasons, availability & cost.

*WOW*

I might have to take that cost one back! When I got mine last fall it was ~$130 for ProX and $120 for Wiseco. A quick look on Rockymountian now shows $120 for ProX and $175 for Wiseco! This is for a 2005 KTM 250SX piston by the way. My Yamaha is a special cluster-f of things.

The sizing issue becomes important only because of the mis-information. The "forges pistons fit looser because they expand more." Despite facts and figures being posted, I promise within the next week (or day) we'll see this appear again.

Its such a sad topic, really. People general believe what they want to with subjects like religion, gun control, motorcycles, and pistons.

Thats funny, but I think we figured out ALL used dirt bikes just had a new piston put in. There are a lot of sellers who would feel bad sticking a new owner with worn out parts.

Lol , or is it the other way round? When they say they put in a new topend recently , "recently" means 30 hrs on the motor... (on a 125 that means its shot already)

I think the MOST important thing is to just let your bike warm up properly before riding , use good premix and jet properly then it doesnt really matter what piston you use. I see too many people at the track offload their bikes , rev the lights out of it for a couple of seconds then hit the track... then they complain that piston X or Y is bad.

Lol , or is it the other way round? When they say they put in a new topend recently , "recently" means 30 hrs on the motor... (on a 125 that means its shot already)

I think the MOST important thing is to just let your bike warm up properly before riding , use good premix and jet properly then it doesnt really matter what piston you use. I see too many people at the track offload their bikes , rev the lights out of it for a couple of seconds then hit the track... then they complain that piston X or Y is bad.

My friend actually put a new wiseco piston in his rm 250 when he sold it. He is one of "those guys" that you would want to buy a bike from. We saved the receipt even that showed it going in on a wednesday and the guy was looking at his bike in Friday. My friend still ended up discounting the bike 75.00 for a new top end.

I believe a good airfilter with decent oil is also mandatory for maximum piston life. After all, you can follow all the warm up, oil and jetting tips, but the first bit of dirt going through will tear things up in a hurry.

As a kid I had a Kawasaki ke 125. It had the speedo with millage on it. We did clean the filter, but oiling was a lost art. That bike still made it over 10,000 miles until the speedo cable broke. I ride it another 5 years after that. NEVER one problem with the top end.

Its such a sad topic, really. People general believe what they want to with subjects like religion, gun control, motorcycles, and pistons.

***************

Please add pre mix + crankcase + trans oils to that list.

OMG , it brings out the Beast in people !!

:p

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