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Discussion Starter #1
Crank is stock. And I don't ride it half as hard as most. There both the same price ($160). What should I get?
 

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Wiseco, I like them better for the 660 and the lower compression will keep you on pump gas where as the 12:1 will need some extra octane with that stage 1 cam.
 

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That'd be news to me, and I spend a decent amount of time on the net watching these things.
 

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Discussion Starter #6
JE had some reported problems of cracking. I ordered the Wiseco 11.1
 

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Discussion Starter #7
Anyone have a estimate of HP improvement from a 11.1?
 

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Discussion Starter #10
We have two old JE's with cracks. I think it's the motors fault not the pistons.
 

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I have ran both of these pistions in both of my motors, first motor was 11:1 wiseco, h/r crank, stage two h/c. skirt snapped off in 6 months, replaced it with another. took the motor apart to replace base gasket 3 month laster and checked pistion, cracked skirt on the verge of braking off. So i replaced both pistion and cylinder thingking it was wore out from pistion slap. 3rd wiseco 11:1 pistion lasted 5 months and blew my whole motor up throwing rod out of the front. rebuilt my whole motor but same parts, stage two h/c, h/r crank, and replaced the pistion with JE 12:1. Ran it for a year and a few months till i changed my oil and totaly forgot to tighten my oil drank plug and yeah you get the end of that story motor stoped solid haha. But it took it apart and the skirts wernt cracked or broke so i guess JE makes a better pistion IMO And i repalced that pistion with the same but bored it to a 686 and 12.1.5 or 12.5.1 i cant remember what it is now but its been in my bike sence sept 18th and still runs 100%.
 

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Over 3 years on my 11:1 100mm wiseco, two of which with the same crank Raptorboi has and a Barker top end, engine ran great. Piston is now in another member's atv in Colorado, still running great.

Over 3 years on another 11:1 101mm wiseco in another 660, still in great condition despite the decompression mechanism coming apart while it was running.

JE, nice big cracks and holes in the top of the 10.75:1 100-102mm models. Lots of pictures over on bluetraxx.com if you're so inclined to go look. The 12:1 fared better because there was more material in the top of the piston, but were not without their own issues.

Now Raptorboi has clearly purchased his JE very recently, (september is barely 6 months ago), and if it's the pro (or whatever they call their upper tier product) then he has gotten the re-designed piston.
 

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Once you make the decision to up the compression and go to a lighter forged piston and aggressive valve train and cam profiles you've also made the decision to do periodic inspections of the crank and valve train assembly. I wouldn't go more than 70 hours without taking a motor down and inspecting the piston, valves, guides, timing chain, tensioner, rockers, and cam for ware and then reassemble with replacement parts. Higher compression pistons, higher lift cams and better riders will wear out a motor fast. I agree with most everyone on here, I've cracked skirts on JE and Wiseco pistons both but replaced them at inspection time and kept my engine failure to a minimum.
 
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