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Vertex Piston?

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So that's why all the factories ran Wiseco huh? :smirk:

Maybe you should have sat down with them and given that piece of information they were obviously lacking...

They run them because they think they make more power.. What makes forged better then cast? Factories also replace there pistons each race, they use em for power not reliability.. I rather use vertex my opinion

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In the last 5 years I've probably used 6-8 Wiseco, and 6-8 Vertex. I have never had a issue with either. Both performed as expected. I haven't used any other brands. Don't ask me why I go back and forth, because I have no good reason. I have a 07 CR 125 that I just ordered a Vertex Piston for, and I have 03 CR 134 that I have a Wiseco going into tonight. The 134 was bored and plated with forged piston tolerences.

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Actually cast pistons are better for top level racers where they would run in top RPM all the time. Forged pistons are more durable and will last more hours. That is why I like Wiseco, I am not a top level racer and so a more durable piston works better for my style of riding.

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Finding a high level two stroke racing engine with a forged piston is impossible. I am not familiar with any two stroke go-kart engine manufacture that uses a forged piston – in fact they won’t use them – period! All Moto GP two strokes use cast pistons. All of the Rotax powered production GP engines use castings. Honda, for a short while used a forging but gave up on it and went back to a casting for their 500cc bikes. All two stroke dirt bike manufactures use castings except GasGas (Possibly the Husky too). So what do these factories know that the average guy doesn’t? I have read thesecast versus forged debates on Thumper Talk for years now and have not read one thread that has hit on the real reason OEM factories choose castings for two strokes.

Castings contain a much higher level of silicon (18%) versus forged 4032 (12.2%). The silicon significantly improves wear resistance. Wear resistance means extended dimensional stability (reduced piston wear). Dyno a forged and cast piston when new the power is identical – dyno after 10 hours of use and the cast piston will win. All of the oems know this – especially the Kart engine manufactures. Cast pistons maintain consistent power levels longer than a forging this is why castings are so dominant in two strokes.

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Here we go again!!!:smirk::bonk:

Not really. I have been in the business of designing and and manufacturing engine components for twenty years. The above post is quite factual. However, you are correct. Let the games begin!

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Finding a high level two stroke racing engine with a forged piston is impossible. I am not familiar with any two stroke go-kart engine manufacture that uses a forged piston – in fact they won’t use them – period! All Moto GP two strokes use cast pistons. All of the Rotax powered production GP engines use castings. Honda, for a short while used a forging but gave up on it and went back to a casting for their 500cc bikes. All two stroke dirt bike manufactures use castings except GasGas (Possibly the Husky too). So what do these factories know that the average guy doesn’t? I have read thesecast versus forged debates on Thumper Talk for years now and have not read one thread that has hit on the real reason OEM factories choose castings for two strokes.

Castings contain a much higher level of silicon (18%) versus forged 4032 (12.2%). The silicon significantly improves wear resistance. Wear resistance means extended dimensional stability (reduced piston wear). Dyno a forged and cast piston when new the power is identical – dyno after 10 hours of use and the cast piston will win. All of the oems know this – especially the Kart engine manufactures. Cast pistons maintain consistent power levels longer than a forging this is why castings are so dominant in two strokes.

Give it a rest man, this is a dirt bike forum not a shifter kart forum. Plenty of top level kart racers run wiseco, even GP 2-strokes. I'd like to see a dyno to back up your claims but as of right now all we have it your word.

RC and every other factory 250 team ran Wiseco pistons, how much higher level can you get? :smirk:

Edit: Why do you use GP bikes as an example when the Honda gave up on its 2-stroke GP program in 2001, probably even earlier than that, just when forged started to become more dominant in racing? The Aprillia 250 bikes do not run cast and the KTM GP bikes ran Wossner pistons.

Edited by 2strokenut

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They run them because they think they make more power.. What makes forged better then cast? Factories also replace there pistons each race, they use em for power not reliability.. I rather use vertex my opinion

Factories don't care about reliability? What planet are you living on? :smirk:

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Actually cast pistons are better for top level racers where they would run in top RPM all the time. Forged pistons are more durable and will last more hours. That is why I like Wiseco, I am not a top level racer and so a more durable piston works better for my style of riding.

You have to ask yourself, what would team Suzuki run a Wiseco piston in RCs RM250 is they could have made more power with a cast piston? If there was any advantage to cast they would have used one.

Finding a high level two stroke racing engine with a forged piston is impossible. I am not familiar with any two stroke go-kart engine manufacture that uses a forged piston – in fact they won’t use them – period! All Moto GP two strokes use cast pistons. All of the Rotax powered production GP engines use castings. Honda, for a short while used a forging but gave up on it and went back to a casting for their 500cc bikes. All two stroke dirt bike manufactures use castings except GasGas (Possibly the Husky too). So what do these factories know that the average guy doesn’t? I have read thesecast versus forged debates on Thumper Talk for years now and have not read one thread that has hit on the real reason OEM factories choose castings for two strokes.

Castings contain a much higher level of silicon (18%) versus forged 4032 (12.2%). The silicon significantly improves wear resistance. Wear resistance means extended dimensional stability (reduced piston wear). Dyno a forged and cast piston when new the power is identical – dyno after 10 hours of use and the cast piston will win. All of the oems know this – especially the Kart engine manufactures. Cast pistons maintain consistent power levels longer than a forging this is why castings are so dominant in two strokes.

95% of pros and amateurs in the last ten years have run forged, almost all Wiseco. Why is this even a debate? Why are you trying to prove your point with shifter karts?

So let me get this straight, top level racers use cast because they can hold power for 10 hours better than forged, ok. Find me any pro engine that uses the same piston for even 5 hours, 2 hours even. Almost every factory manual recommends changing the top end every 7 hours of race use. According to you, both pistons should be making the same amount of power, until 10 hours. Why then would the factories care about making a piston that maintains power past their recommending service interval? They are covering their asses because they know the piston is not designed to go past its service limit.

Why can't you just freaking admit that a forged piston will outlast a cast if run beyond its service limits, as almost every single rider does? Why is that soooo hard for you? Do you really think the average rider gives a crap or even notices a small percentage drop in performance? The average rider doesn't want a piston shattering inside their engine, which happens almost every day on TT it seems.

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Why can't you just freaking admit that a forged piston will outlast a cast if run beyond its service limits.

This is true. If you run your pistons until they are way past worn out and wobbling in the bore from excessive clearance, the forged piston will handle it better.

If your clearances are in spec, the cast pistons are preferred, especially when running at the thermal limit. That is why pro motocross and shifter kart engine builders usually run cast pistons.

The OEM's all spec cast pistons for their 2-strokes because they perform better in most situations. If forged pistons performed better, the OEM's would spec them from the factory.

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The point is factories have done all of their testing and the conclusion is obvious - a casting for two strokes is the best. Karts and GP are harder on pistons than MX and what do the factories supply their two stroke engines with? A CASTING! Sorry there are too many real factories (KTM,Honda,Yamaha,etc) backing up what I already know!

One final point if you are going to debate with someone you need to learn to argue facts. You continually use referential logic!

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The OEM's all spec cast pistons for their 2-strokes because they perform better in most situations. If forged pistons performed better, the OEM's would spec them from the factory.

Exactly! And REAL factory bikes run castings.

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