Speedfight acceleration problems

xteam · L Plate Warrior Joined: 09 Jun 2009 Karma :

My speedfight has just developed a problem where it refuses to accelerate for a long time after it has been started (even at low throttle) when the engine gets warm (after around 10 minutes of trying to accelerate) it accelerates fine most of the time. It also has a flat spot when its running at around 20 mph

Any Ideas?

o and its a 50cc x-team speedfight 1 (liquid cooled with rear disc)

xteam · L Plate Warrior Joined: 09 Jun 2009 Karma :

its also been derestricted but has standard exhaust

andys675 · World Chat Champion Joined: 08 Feb 2007 Karma :

could be a loose spark plug

prawny1 · World Chat Champion Joined: 28 Jun 2005 Karma :

you may have an automatic choke problem, not sure really how you test if the choke/ power supply or what the readings should be i replace them with manual if i suspect a fault ( 9/10 ive been right),
It would be worth fitting a manual choke conversion (whether yours is faulty or not, it will go at some point) they cost about a tenner from pm tuning.

Ive never liked the idea off these types of chokes on scooters, they should work fine in theory, but once the bike has warmed up the power is turned off, they are meant to then rely on heat from the engine to keep the choke closed off,

I would much rather have a proper lever to put the choke on when its needed and off when it's not, at least you know that when your off choke your fueling is right and consistent (prevents seizing/ plug fouling etc}

andys675 · World Chat Champion Joined: 08 Feb 2007 Karma :

easy to test the choke, take it off, hold the end over a ruler and wire it direct to a battery, there should be a marked difference in the length the valve comes out of the body of the choke unit after 5 minutes

baldy · World Chat Champion Joined: 16 Feb 2004 Karma :

Your rollers could have developed flat spots which causes them to stick, resulting in it being stuck in a "higher gear" so to speak. It would be like trying to set off in 3rd or 4th in a car, you would have crap acceleration. Has the bike done a lot of miles?

bass2k8 · Nitrous Nuisance Joined: 13 Feb 2011 Karma :

Hey, I'm having the exact same problem as xteam is. My speedfight has very bad problems accelerating past 20mph... I was wondering whether you have fixed this problem xteam or not? Did you purchase the manual choke kit and did it work fine? Thanks.