I just put a new carb on my 77 Puch Maxi. The bike starts, and runs, but, when I start it, for example, with the kick stand down, the back wheel takes off! I mean, it is like I have the throttle all the way open, but it's not. If I pull the throttle, it goes even faster...too fast...like, my bike is going to blow up fast! Is this a idle problem? Is there a screw of something that I can turn to adjust this? Please help!
Well,Chris,I just looked in my Puch manual and it shows a common looking idle adjustment screw in the side of the carb.Back this out with the bike warmed up until a slow steady idle is attained.If this isn't the problem,you may have an intake air leak around the carb -intake connection or at the intake-jug connection,but when mine did it the other day it was a MASSIVE air leak at the cylinder jug base gasket.
Don,
I also replaced the air filter, I think. Isn't that the black thing on the side that hooks over the opening of the carb? It seemed wierd. Like, there was this hold in the side of my bike, and this white hose that attached to it. Any thoughts? I also think it might be kinda loose where it is attached to the cylinder head.
Well Chris,just make sure there's no inleakage of air.My manual doesn't have that pictured so I'm at a loss of what the tube is.Did you try to adjust the idle speed with the screw yet?
Remove the airbox and with a flashlight look in the intake to the carb. Turn your idle screw out to begin with. With the throttle on low, the throttle slide in the carb should be fully closed. Operate the throttle grip while looking in the carb and watch the action of the throttle slide. It should fully open and fully close. If it is not, you have to adjust the throttle cable length until closed. Then, turn the idle screw until the throttle slide begins to lift.
Where would an intake air leak be? Could it be that the carb isn't bolted down on the cylinder head tight enough? could it be where the carb meets the airbox? I have a real dilema here.
Yes,Chris,it would be Carb to intake pipe,or Intake pipe to jug,OR as I found out the other day,cylinder jug to block.Just drip some carb cleaner around these points without letting it pull in thru the airbox and if the rpm increases or changes much,then you have found the air leak.When I sprayed carb cleaner on that jug base the bike revved so high it started to back up with vibration!Only after making a new gasket and installing it could the Cosmo be `Idled down' to normal with the idle screw.AND NO,it's probably not where the carb meets the airbox.BYE!
How do I adjust the length of the throttle cable?
Want to post in this forum? We'd love to have you join the discussion, but first: