Speedfight 50cc Air Cooled 03 Problems

Hey guys,

I'm new here but have been browsing for some time! You guys have fixed some of my problems !

I bought a shed of a speedfight last year, the crank splines went on it and i had to rebuild everything! Currently in the bike there is a "race" crank, malossi clutch and variator and a dayco belt. 5g Rollers. The bike has a gianelli chrome exhaust on it (I believe it's an Extra) with a carbon can. it's also got an after market air filter. I've jetted the bike for the exhaust + filter but i'm having a few problems.

1. It only does 40mph (My dad thinks it might be the barrel as when i bought it; the guy said he put a new piston in it but didn't have it re-bored)
2. Full whack throttle and there is a few seconds delay before the bike sets off (I think it might be clutch spring)

If you could help with these it'd be awesome!

Also; could someone advise me? I'm after a 70cc Kit and i've got the choice of Malossi (£125) and a Polini one (£100)... Which would be best? Would I have to change anything on the bike to fit it or is it just a straight bolt on? Are the expansion chambers any good as well? The boost bottle things?

I've learnt a lot from stripping and rebuilding mine; but this has me stumped!

Cheers guys!
Danny

 

Re: Speedfight 50cc Air Cooled 03

Is anyone able to help?

Cheers

 

is this when the bike has momentum? or of a stop? if ure doing about 20 and u close the throttle and open it and it goes slowly, this is usually to do with ur rollers "dead spot"

of the start its just ur clutch springs but it shouldnt be that bad?

 

I've just put brand new rollers in it. It still does it; the throttle response is apauling when there is no revvs but if the bike has revvs on above a certain amount it'll fly. Soon as i'm above that amount, it picks up really well. I can't remember if it did it with the standard exhaust on it as atm i've got a gianelli chrome extra which had a hole in it (had it welded).

Thanks for the reply!

 

clutch springs id say.

does it bog? struggle to move? could be ur idle screw

 

The air mixture screw is fucked and since rebuilding; it won't tick over unless it's on choke... i'll take my carb off at the weekend and fuck about with it lol... It doesn't bog, just builds revs up and then all of a sudden sets off.

 

Sounds like the clutch to me, being centrifugal, at low revs it's slipping then at higher revs it "bites" and your away!

 

Its got a brand new race clutch and bell in it though? But i have no idea which spring needs to be in it, i just put in the spring that came with my malossi variator. Can you guys suggest what i should do? Cheers!

Dan

 

its about the stiffness of your clutch springs, not about how new it is. also you say you got new rollers, did you go lighter or heavier than standard ?. lighter id reccomend, somewhere between 1 and 2 grams lighter but you find the right setup for you, had similar problems with my ice, the pull away im 95% sure is your clutch not having stiff enough springs ( about £15 for a pack of different strength ones) just try a few different strength springs untill it feels better to ride