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polini corsa help

Posted: Sat Jun 04, 2016 7:22 am
by creativelolo
I got a sym dd50 72cc.. was trying to get the most mph out of it. I maxed out at 65mph but I know I can go faster. I'm still learning how to properly tune and need help.
The set up: polini corsa, 28oko (142 main didn't touch piolot so idk), 33.3g rollers (three 5.3g three 5.8g), 1k center, yellow malossi clutch, kelly pulley/ramp, malossi torque driver, malossi delta clutch, polini bell, 7:1 gears, v8 exhaust, ebay cdi..

Was thinking of adding that 44mm ab crank (plug and play right? No mod ding block?) + arrow pipe.. any suggestions? I also read here on these forms that a 24mm carb is a better option than the 28mm (hawaii guys over do it a lil bit I guess).. idk, im learning

Re: polini corsa help

Posted: Sat Jun 04, 2016 3:45 pm
by Wheelman-111
Greetings:

Your setup making 65 MPH is no slouch already! Lots of posts and my own experience suggests that your V8 exhaust may be limiting RPM and top speed most of all. 7:1 is really too tall for even a robust 72cc. You could actually go faster with 8.44s or 7.98s. And not knowing what your pilot jet size is? Really? I recommend you find out. Whatever size you have, the carb's air mixture screw should adjust to best idle at about 1.5 turns out from lightly seated. If it needs more turns than that, you're too rich. If less, you're too lean. The 28 can be tuned to run on an engine that revs very high, but matching it to a V8 pipe certainly isn't ideal. The 24-26 sizes tune easier.

Anyway if you keep going much faster, I hope your Sym has a disc brake.