Race bike issues

[Chaos Mk1]

Hi guys,

Got my race bike going after a bit trouble. So I took the old girl apart and did all the usuals, I cleaned the carbs, replaced the HT leads and plugs along with new spark plugs. New air and fuel filter, cleaned the fuel lines and go t rid of the old minging fuel. Basically all your standard things for new bike.

Now for the problem. It fires up ok but the revs jump up to about 4000 and hold for a while and may drop to normal Idle but not smoothly. If it does go to idle it will jump up higher again. The long and short of it without going on, the revs are completley erattic jumping up and down and the engine will cut out without a blipping of the throttle, but holds its revs when you do. The throttle is snapping shut so its not that.

This probably isnt the clearest description but if anyone can suggest something itd be much appriechiated. Cheers guys, Chaos.

[Mori Man]

Sounds like you've shifted muck/gum from one part of the carb internals to another part and its causing problems

Now that they have had a doze of fresh fuel in them strip them down again and blast them out with a quality carb cleaner - I only ever use Mikuni as it lubricates but it also shifts the gunk with little effort . After that a bottle of additive in the fuel that also cleans should help.

You've most likely knocked the sync' out on them so once you can get them to rev constantly borrow some vaccum gauges and set them up again.

MM!

[Chaos Mk1]

Ok perfect, ill give it a go tonight. Cheers.

[Fatspanner #44]

Sounds like an air leak to me. Check the carb inlets to make sure they are sealed and also make sure the carbs are seated properly.