Motorcycle Forum banner

1 - 6 of 6 Posts

·
Registered
Joined
·
1 Posts
Discussion Starter #1
Bike runs and rides great until about 15 mins in and I get on it then bike misfires and only runs on 2 cylinders but if I pull over and let bike sit for 20 minutes it will be fine until 15 minutes again
 

·
Super Moderator
Joined
·
12,406 Posts
Welcome.

Putting things like ASAP in an appeal for help won't really get you replies any faster.
If it really is THAT urgent, you should take it to a shop.

Could be a plugged tank vent; try opening the gas cap when that happens.
Could be a fuel pump going bad.....if it has a fuel jump.
Or a plugged fuel filter.
Or an ignition component failing when HOT.

Some testing will be needed.
 

·
Registered
Joined
·
6,802 Posts
Also the carb floats may be set way too low, or one or more needles are sticking. Like Ken says the tank filter may be clogged...pull the fuel valve out to check....on a bike this old it will be the old style filter which is little more than a mesh screen fitted to the fuel valve. Empty the tank first or have a low fuel level so you can tilt the tank. I would stongly suspect it is a fuel delivery problem.

Good luck
 

·
Registered
Joined
·
17 Posts
I was thinking an air leak. I'd spray WD-40 along all the gasket seams on the failing cylinders. Also the hoses. If you spray on a leak you will hear a change in how the engine is running.
 

·
Registered
Joined
·
165 Posts
I had an old bike that did the same thing. It turned out to be the caps on the ignition wires that connect to the plugs would expand/weaken their connection when they got hot. It was a simple repair, but took a while to find.
 
1 - 6 of 6 Posts
Top