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Discussion Starter · #1 ·
hello..im new here and new to 4 strokes..i have a ?..i got a stage 1 hotcams and im planning to install a new piston to raise the comp..im wondering how much i can raise it with stock internals..hotcams is not installed,while im there i will port the head.,I saw a JE piston with a Comp Of 12:1 compared to wiseco 11:1..if i go with the JE will i gain a few extras ??thans
 

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Here's a little tip for you. 4 strokes love high compression. The higher the compression the more power you will make (untill a point), but most of the time the limiting factor is whether you want to run pump gas or race gas. 11:1 is fine on premium pump gas, but with a 12:1 piston you will need a higher octain of fuel. Also I would stay away from the JE pistons. They have been known to crack in the 660 engines. CP also makes a 12:1 piston that you can run, if you want to run higher compression than the Wiseco pistons.
 

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Discussion Starter · #3 ·
thanks for the reply..i guess ill stick with the wiseco since the premium fuel here in my country is the worst in the USA..and race fuel is quite expensive..where can i get the cp piston? thansk
 

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What kind of curve do you get with the wiseco and the stage 1 hotcam, still good for trail riding?
 

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rappyfreak said:
What kind of curve do you get with the wiseco and the stage 1 hotcam, still good for trail riding?
"STILL" good for trail riding? Man that thing will pull stumps compared to the stock setup. You'll be very comfortable with the power in most trails, the only time you'll be wishing for a bit more is top end runs on long fire roads.
 

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Stock bore is 100mm
Next available wiseco is 100.5 with the stock stroke displacement is 666cc
then 101mm, 673cc
and 102mm, 686cc

Unless your looking for a bigger motor your best off getting the next size piston, provided the cylinder is in good enough shape to bore that amount. If the motor ran most likely you'd be OK, the cylinder would have to be very out of round to not clean up for the 100.5 bore.
I did mine recently and went with the 101 bore, it gives the machine shop more material to work with and you still ahve the option of boring it a second time with out resleaving or haveing case work done for the 105 bore.
 
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