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Powroll High Compression kit

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Has anyone installed powrolls high compression piston kit in their bike yet? I'm having a hard time justifying $220 bucks for a bare piston, and I'm wondering how much it really helps. I've also heard that the crf150 crank bearings do not hold up well against the high loads of increased compression? I'm just trying to get as much reliable power as I can before I go the big bore route.

Bob's 150

`03 Crf150 BBR pipe, Rev box, web cam, 428 conversion, stiff springs

`04 Crf150 PC pipe, Rev box, wev cam, stiff springs

`02 Ttr125 Yoshimura Pipe, weisco cam, ported head, 26mm carb, stiff springs

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Thanks for the input. I just put my 428 non o-ring kit from spocketspecialists on my bike, and it's a major improvement. I can't remember my new sprocket sizes, but I know that they are the same ratio as a plus one rear sprocket over stock.

Bob's 150

`03 Crf150 BBR pipe, Rev box, web cam, 428 conversion, stiff springs

`04 Crf150 PC pipe, Rev box, wev cam, stiff springs

`02 Ttr125 Yoshimura Pipe, weisco cam, ported head, 26mm carb, stiff springs

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Why not just get a big bore??? It's not that much more and there is a big difference. Don't worry about the bearings, my friend did his to a 252cc, and the tranny broke in one day. But he does supermoto. That's what you would need to worry about or the crank itself. But it seems most guys can run up to 175cc high compression with no problems.

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The big bore kits are what I'm trying to stay away from. I don't have anything against going larger, but I want to pull as much as I can from my stock displacement first. Plus most of the mini 4-stroke races down here impose a 150cc limit.

Bob's 150

`03 Crf150 BBR pipe, Rev box, web cam, 428 conversion, stiff springs

`04 Crf150 PC pipe, Rev box, wev cam, stiff springs

`02 Ttr125 Yoshimura Pipe, weisco cam, ported head, 26mm carb, stiff springs

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Wait for one of the other guys on here that has the high comp piston. I think his name is 04CRF150 or something like that. He had it for only a few months before blowing it. Now he has fully modified the motor with a 175 kit and all that. I think your better off doing other things.

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I don't know where you race, but I don't think anyone is going to check. Although, you are probably one of the few honest people racing by sticking to the 150cc limit. 😢

There's a stock xr100 class in the crmma (or whatever) and it's comedy how fast those "stock" bikes go. If you showed up with anything less than a fully modded 120, you don't stand a chance. I think I only race a stock bike twice in a stock class. It got so bad that now at the four-stroke national at Glen Helen, it's limited to air cooled, 2 valve motors, because the 150cc limit was unenforceable.

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Yes, i put the 12:1 comp piston before the big bore kit. But i did it with all of the stroker, cam, and exhuast. I ran Oxygenated fuel in it and blew it up. So i had to bore it to the 170(which makes my bike a 203). The 12:1 isnt really worth it unless you do the cam, and exhuast cause you have to run race fuel. In my opinion the 170 is alot better. Its easier to start and it has just as much hit and pulls longer in every gear. Pm Me if you need more help. Or Coeshow.

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Actually if you want i may be able to sell you the 12:1 piston that i have for like $150-$170. The piston is fine but the ring is the thing that scratch the cylinder( the piston had alittle scratch but we sanded it down cause we were goin to put it in my dads bike but now im putting my 170 in his and getting me a 187 kit. I will also include a new set of rings with it for $200.

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I have the powroll cam, and powroll high compression piston with other mods. I stayed with the stock bore because Im in the houston area as well and want the bike legal. I havent ran the bike all that much, it seems to be holding up fine, I have been running the dog out of it! It is not a blazing fast bike but it is a lot more fun. I believe that the main advantage of the higher compression is to make up some of the lost low end due to the cam. I have been running leaded race gas 110 octane (a must)

Good to see that someone else cares about staying legal. Sure Ill see you around.

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Thanks for all of the input everybody. I've got a couple of more tricks to try before I actually tear into the bottom end of my bike, but it sounds like that the 170 kit is the way to go. Sk8fasst & 04hondaCRF150F, where do you two normally ride at? It would be nice to get a group together at one of the local tracks.

Bob's 150

`03 Crf150 BBR pipe, Rev box, web cam, 428 conversion, stiff springs

`04 Crf150 PC pipe, Rev box, wev cam, stiff springs

`02 Ttr125 Yoshimura Pipe, weisco cam, ported head, 26mm carb, stiff springs

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I ride over in Fort Sumner, New Mexico and Melrose, New Mexico. I ride trails in Canadian River(Amarillo, Texas), Lake MacKenzie(Tulia,Texas) and Haystack Mountain(Roswell, New Mexico.) Im goin to start going down to Idolul, Texas to start racing. I live in a small town on the border of New Mexico and Texas but on the Texas Side. Its called Farwell. If you can find Clovis New Mexico than you can find me.

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I normally ride at Three Palms on Sat and at 290 on Wedensday afternoon/evenings. I was thinking about going to check out the indoor Nash track one Sat. Look for #8 CRF 150.

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I rode nash last night. It's a neat track, but it's more suited for smaller bikes. I actually had more fun on a stock klx110 than I did on my 150. If you do go and ride it get ready for a workout. They are only open on Tue. nights and Sat. Jerry, the guy that runs the place, does a really good job, and he's very nice.

Bob's 150

`03 Crf150 BBR pipe, Rev box, web cam, 428 conversion, stiff springs

`04 Crf150 PC pipe, Rev box, wev cam, stiff springs

`02 Ttr125 Yoshimura Pipe, weisco cam, ported head, 26mm carb, stiff springs

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