surging on a '77 GS400X

[simon_C]

hey folks, just found this place!
ive got 1977 GS400X i picked up over the winter. im going over everything making sure everything is ready to ride for when i get my permit.


anyway, my problem is, when i take it around the block for a short ride, sometimes the RPMs will surge at idle. its usually at exactly 3000 RPMs. it doesnt go down until i full throttle it and let off again. also, sometimes when i accelerate hard, itll bog down a bit.... im thinking my floats might be sticking, but i havent checked it out yet. im gonna pull the carbs apart and clean em, see if it helps.

ill try to get a few pics of the bike with the new tires and chain once theyre all on, im waiting for the new chain to come in the mail. im trying to make it look a little sportier.

-Simon

[Guest]

Floats won't have much to do with it...

sounds like you have an air intake leak...

Check all the clamps and rubbers for cracks...

[Nessism]

Large O-rings trapped between the cylinder head and the rubber carb boots dry out allowing them to leak - suck air "in" actually. This will lead to an inconsistant idle (usually high). Sometimes the boots themselves dry out as well so you should inspect them carefully after taking them off.

[80GS1000]

I'm with the other guys. You'd be doing well by replacing your intake boots and o-rings to solve the air leak.

[simon_C]

well i checked them over, the boots and gaskets look brand new (the PO had done some work on the bike). i checked everything for tightness but its all tight. it only happens when when bike has been running for a while, when i come off the throttle. im probably gonna pull the carbs apart today if i can.

oh, and any tips for switching to pod filters? i ask because all the electrics are mounted to the airbox. but theres also that rubber boot between the carbs and the box, think theres enough room in there for pods?

OH! it just struck me, i forgot to mention i put a MAC 2-1 exhaust on here not too long ago, but it was having these problems with the stock pipes too. i probably need to re-jet dont i...