wont start after doing nearly everything i can think of doing. the bike has a new 172 topend, technigas exhaust, filter and 92 jet. bike has new battery it sparks fine fuel getting in carb cleaned when it does start it gets very hot and cuts out again, then wont start for about 30mins. am abit stuck on what it can be. any help would be great
has it ever run well? is there some mod you have done, where this has started to happen? what carb you running?
it did run well till the piston rings went. so i got the 172 kit. Its got a 20.5mm carb. the only things that i have changed since then is main jet, battery, plug, fuel, oil, cleaned carb. lowered needle (raised clip). i have tried loads of adjustments to bike but just cant get it rite. the plug is black and wet after it cuts out. i thing that is running rich, so thats why i lowered needle but wont start at all now.
Put the needle back to its original place and down jet a little & lean out the mix screw a 1/8th turn then replace that spark plug with a new one. Running rich will kill the plug thats probably why it wont start now. Give that a try!
ok i have done that. i press starter and bike fires up when pressing starter, as soon as i let go of starter it cuts out.
as you screw it in, it cuts down the air flow, richer. You need to screw it out. always wise to screw it in, count the turns, and then screw it out. That way you can remember the original setting ......... if you need it. clockwise makes it rich. anti-clockwise leans it off.
Will it stay running now when you keep it revving? You say its not ticking over (cuts out when throttle is released), but will it stay running if you rev it and have you taken it for a spin to see how it runs?
no not got it going yet. i have just ordered a new carb as i have done everything else. will let you all know if this resolves problem
Nice, what carb did you order? If you were running the Mikuni VM20 or Dellorto 20.5mm, then a bigger carb will be a nice "step up" anyways. Probably wont resolve the problem but it will give a nice power increase when you get her running nice. Did you check the choke was working on the old carb? If the chokes not working fully, then it'll be ever so hard to start or even fail to start at all. And always check you have a good spark plug, this is 90% at fault with non-starters and most commonley forgotten!
i ordered a new carb because the auto choke was stuck half way, i am sure this will be the problem. i got a standard 20.5mm dellorto carb for now, spent too much this week. just want it running again.
