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Wiseco High Comp Pistons??

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We are in the process of rebuilding my YZ450 for SM. My question is regarding the Wiseco HC pistons. Are they worth while :naughty: ? We were about to install one along with Hot Cams and an (undetermined) aftermarket exhaust.

Anyone have suggestions as far as exhaust?

My bro will actually be racing the bike at his WERA events, so it's mostly road courses for this bike. I'm sticking to MX for now :naughty:

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I would stick with stock.

Every Weisco High compression I know of failed in a YZ450, that is 6 of them, one resulting in personal injury.

The bottom of the piston hits the crank and eventually taps the wrist pin shut and seizes and breaks out the boss.

That's why I warn people not to use them, but some people don't listen so take warning and do what you want, it's your money.

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Wow, 6 of them huh? I wonder if Wiseco knows about this problem. The bottom of the skirt hits the crank?

I guess stock it is...

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RAD,

What brand of high compression piston would you recommend ?

I planned to put in a WISECO and run race gas in my 250F this year.

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DR.D would probably be the best exhaust for your Yamaha seiing as Doug Dubach is Yamahas test rider.

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Weisco are retail over the counter pistons, I would go with the J.E. piston, the same company owns both but there is a huge difference between the two company's as far as quality. I heard someone tell me the same thing happened to the J.E. piston.

J.E. are run by the NASCAR guys like Jr., you know they are of the utmost quality when that happens.

Personally I had both my cranks relieved before they balanced them so this wouldn't happen again.

I wonder what weisco did to rectify the problem? I have talked to their tech department before and wasn't impressed with the answers they gave me about the problem or their willingness to look into the mater any further.

There is no way I would want to be a Ginni pig to see if they fixed the problem, it isn't like they don't have any of the bad pistons floating around after making them for 2 years.

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I heard that the problem with JE was that in 05 Honda changed the location of the oil nozzle and people were trying to run 04 pistons in 05's and the piston was hitting the oil mister causing the motor to blow. Apparently they are making a diff piston for 05 that fixes the problem.

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Trice told me they took some material off the Boss but I would check it before install.

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Weisco are retail over the counter pistons, I would go with the J.E. piston, the same company owns both but there is a huge difference between the two company's as far as quality. I heard someone tell me the same thing happened to the J.E. piston.

J.E. are run by the NASCAR guys like Jr., you know they are of the utmost quality when that happens.

QUOTE]

All the guys from JE went to CP after they got bought out.

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wiseci High compression piston works fine for me with race gas and a flowed head, perfect.

Mark

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I ran the Wiseco high compression 97mm in my son's '03 450 all last year with no issues. Took it apart and it looks like it's ready for more (needs rings is all) pin bore & wrist pin are fine too along with no damage to crank or piston skirts.. JE makes a great piston as well.By the way, the Honda "05 can use the '04 piston if you relieve it to clear the piston squirter (Hmmn, would the Wiseco also clear the crank if it would have been relieved/checked? :naughty: ) Is CP currently making any dirt bike pistons? They will/should be good also. Vertex should be real good too, although I currently have no experience with their products. By the way, with the 97mm high comp Wiseco, Hot Cams, ported head & Full titanium Jardine system it made 53 rear wheel HP.

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