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2-Stroke Jetting / Power Band


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I just put together a 87 TRX 250R with a completely new 320 stroker and my first run to the dunes has me scatching my head a bit. The jetting seems dialed in and over all it ran very good but the rpm range to get to the power band seems high, which made it hard to pull the hills in second gear. It would bog down unless I kept on the clutch and that usually meant that I had to go faster than I wanted to. Is it possible to change this with the jetting or do I have the wrong pipe or.... do I gear down? I'm running a Pro-Circuit Platnium pipe.

Any advise out there?

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Dream Car Giveaway

I would try gearing down a tooth in the front... Thats what i had to do with my banshee so i could launch in second when we sand drag... there are a few factors that could be messing with your power band...

What paddles are you running, how tall andhow many paddles do they have? I went from 20 inch sand stars to 21 inch 8 pdl haulers...

Did you have any porting done along with your stroke? It can effect when your powerband kicks in to...

you might do some research on your pipe, they are built for different powerbands too... I have CPI's on my banshee and they are high rpm pipes but they scream when they get up there...

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With the extra power that you should gain with a big-bore stroker, you shouldn't need to gear down unless you are running larger rear tires. Infact with that kind of power increase, you should be able to pull higher gearing. However, like jigobeep said, some times gearing down is optimal for ceartain situations like dragging and hill shooting. He also mentioned porting, did you have any porting done? Also, pipes made for a stock bore 250 weren't really designed for a big-bore. Curtis Sparks, FTZ, and ESR as well as others all make good pipes for that. I have always heard of people having great resulsts from the ESR TRX-5Centermount on thier big bores.

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