yasuni c21 bogging down my aerox!!

[nstar]

hi guys..
i now brought a pollini evo3 cylinder so i can use my yasuni c21 iv had layin around for a while after gettin cheap online. the only problem now is that my aerox wont move it's lackin so much power. i put a leovinci zx on and has no probs.maybe the evo3 exhaust flange isnt a match for the c21?... i got a 21mm dellorto carb on it, maybe being small is restrictin the fuel/air for the exhaust requirments? or something else is bogging it down any help or info much appreciated cheers.

 

[evo-2 Runner]

This sounds like a rollers/clutchsprings and jetting issue...

The C21 will need much lighter rollers, and stiffer clutch springs than a leovince ZX :#

 

[nstar]

thought it might be a transmissions set up session again. back to the tidious trial and error 8Pi might aswell buy a 28mm koso or keihin while im doing set up work get it all done at once :winner:

nice 1 for the replie thought the site was dead as no 1 responded :r

 

[evo-2 Runner]

your welcome buddy

 

[SF2B]

It should run great with the 21mm too, but you will gain like 1 HP with a nicely adjusted 28mm.

 

[nstar]

yea 21mm is a pretty good carb. only problem is when i tried using it facin backwards usin a straight manifold it just didnt want to know.. tried main and slow running jets but no go.. so hopefully 28mm keihin or koso flat slide will work easily as they a used alot. if any 1 has any tips on rear facin set up let me know
thanks

 

[evo-2 Runner]

The 28mm carb is the best for top end power, but if your thinking about riding on the street, go for a smaller carb...

with 28mm carbs the air velocity through the carb at small throttle openings will be very low, meaning there wont be too much depression over the main jet.

in simple speak your engine will be running quite lean at part throttle, which will cause your engine to run too hot...

This isnt such a problem at full throttle, as the revs climb so does air velocity, but for street use you may be at part throttle more than you are at full throttle....so err on the small size with carbs for street use <]

hope that helps

 

[tiba_karotsu]

the ZX is designed for kits that make power under 10K rpm, the C21 makes power from 10K to 14K rpm so it will definitely need running very light weights, very stiff clutch springs & vario spring.

i run a hyper tuned MHR Team 6T kit, Keihin PWK28 (the real deal), C21, Kundo PVL inner rotor, Polini SS9 vario & 128mm rear pulley, Delta clutch & wing bell, my settings are 18g rollers total, black clutch springs set at max tension, malossi red vario spring with torsion controller. this setup has no power under 9K rpm so it's good for racing use only but it you want to street your scoot a bit tone down the tuning by using a smaller carb & different pipe that makes power at a lower rpm range like a C16 or R1200.