Hi there, I have recently bought a dodgy speedflight 2 2006 reg, I got the bike realy cheap as the owner didn't know what the problem was with the bike. Whenever I start the engine it ticks over fine but as soon as I pull the revs back the revs shoot up and then after a few seconds the bike dies right back down to virtually no revs again and just about ticks over again If you pull the revs back again it just bogs out and eventually cuts out. If I start the bike again I have the same problem. I have cleaned the card and put a new air filter in. Would it be something to do with the fuel mixture being wrong Or could it be something more serious like the piston ring etc..

Steve, June 2008

leave it for about 5 mins cuz it might be auto choke

liam, September 2010

I had same problem but possibly 2 different faults.
1st-following changing crankshaft bearings, earth to battery not good. Wire up from chassis to battery to solve the problem.
2nd-problem is with freezing carb on very cold days. Once warmed up after 3 miles, not problem

Simon, February 2010

it will not be the piston ring get a new carb soounds like the mixture i had a problem like that i got a new carb it was fine

danny, February 2010

it might be the size of your jet in the carb it should be 54

danny, June 2008

have the Workshop Manual for that bike, It includes loads of fault finding help, Pictures, Part lists & wiring diagrams etc. If you would like a copy email me @ slippery.steve@ntlworld.com

Or look at my small guide I posted @ http://www.howtomendit.com/answers.php?id=143363

Best of luck!

Slippery Steve, June 2008