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Ok i been reading around. I was wondering if anyone puyt a high compression pistion yet in the YFZ? If so what Compression ratio,and was there a noticeible difference over stock? Ok thanks
 

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I just installed my 13:1 GYTR piston got it from Bob @ Magnolia Tractor.

I have not ridded it much yet but will this weekend at Dumont and repot back.
 

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With a pipe, cam mod and 13:1 piston, you'll think you're on a different machine. I was running 13:1 before I broke, now I'm 12.5:1 @ 467cc.

For ~ $180.00, a high compression setup is the way to go.
 

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i have been thinking about doing that myself was wondering how big a difference it made

andy
 

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Originally posted by wildman77@Nov 25 2003, 10:33 PM
i have been thinking about doing that myself was wondering how big a difference it made
Definately a good/required mod for $180.00. You'll need to run race gas though. I've run anything from straight 112 to 60/40 110/91 and have never had a problem. Obviously the 60/40 110/91 is the least expensive way to go.
 

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would av fuel be alright with the piston can't find race gas anywhere around me

andy
 

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Originally posted by wildman77@Nov 26 2003, 10:53 AM
would av fuel be alright with the piston can't find race gas anywhere around me
I personally have no experience w/ AV fuel, but I do know a guy who runs it in his shee. He runs AV 'cause of where he can get it in relationship to his house. Whereas I can buy 110/112/methanol/etc. 5 minutes from my office.

I'd do a little research first.
 

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Originally posted by selector@Nov 25 2003, 07:13 PM
With a pipe, cam mod and 13:1 piston, you'll think you're on a different machine. I was running 13:1 before I broke, now I'm 12.5:1 @ 467cc.

For ~ $180.00, a high compression setup is the way to go.
where did you get the 12.5:1 and how much did it cost to bore out your block or did you do a completely stroker?
 

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where did you get the 12.5:1 and how much did it cost to bore out your block or did you do a completely stroker?
I got the 12.5:1 98mm piston and head gasket from Mickey Dunlap ~ $210.00

I had Millenium Technologies bore and plate the cylinder ~ $230.00
http://www.mt-llc.com/index_home.shtml

Got the intake/filter/42mm carb/jets from Ron Wood Enterprises ~ $650.00
www.rotax.net

My stroke is still stock, but the bore is now +3mm.
 

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Originally posted by selector@Nov 26 2003, 10:51 AM
I got the 12.5:1 98mm piston and head gasket from Mickey Dunlap ~ $210.00

I had Millenium Technologies bore and plate the cylinder ~ $230.00
http://www.mt-llc.com/index_home.shtml

Got the intake/filter/42mm carb/jets from Ron Wood Enterprises ~ $650.00
www.rotax.net

My stroke is still stock, but the bore is now +3mm.
Getting the piston, boring, and plating the cylinder is about the price of a pipe...give aor take some...But would it be better to go with the pipe 1st, or do the other stuff??
What do u think...thanx
 

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Originally posted by wildman77@Nov 26 2003, 08:53 AM
would av fuel be alright with the piston can't find race gas anywhere around me

andy
AV is verrrrry dry fuel. I have a friend with a high compression 383 stroker in his chevy truck when he runs that stuff at the drag strip he always adds alittle transmission fluid to the tank says it helps make up for the dryness. I dont know how it would work in an atv but it hasnt hurt his truck yet.
 

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Well I finally got to really ride the bike after the piston install, and allI can say is WOW $180 bucks WELL spent.

Much more torque all over, seems like it may rev a littlw slower but overall a noticible power increase all over the entire powerband.
 

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Well I finally got to really ride the bike after the piston install, and allI can say is WOW $180 bucks WELL spent.

Much more torque all over, seems like it may rev a littlw slower but overall a noticible power increase all over the entire powerband.[/b]
what brand piston and whats the copression, and where you find it for 180?
 

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what would a good hc cp piston be for the +3mm crank? i was thinkin of getting a cp12.5:1 because im affraid to go too big with the wicked 13.5:1 piston. what you all think about 12.5 with +3mm crank?
 
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