Possible carb issues

[steer_rally]

I have an intermittent problem (another one ) with my pre-diversion XJ600.

Sometimes, about 50% of the time in fact, the revs take along time to die down when I close the throttle. This can happen when changing gear (makes gear changes less than smooth), waiting at junctions (embarrassing), or just when wanting to slow down approaching corners etc (no engine braking, excess use of brakes).

The cable is free, and mechanically the carb linkages all seem to return ok, so I'm wondering if the carbs being out of balance could cause this? Or could the fact that it doesn't happen all the time mean that something inside that carbs is sticking. I'm hoping to borrow a carb balancer soon to check the balance, but in the meantime has anyone experienced this or have any suggestions?

Many thanks

[Guest]

start the bike and spray the area around the carbs with wd40, if the rubbers have perished and it is taking in air from outside the revs will climb. if this happens you need to replace the rubbers, most likely on a older bike..

split inlet rubbers or a bad seal will cause this. (engine to carbs)

[Anthony]

double check the throttle cable, my bandit used to stick open if it was on full lock, could be that yours is similar

[rosszx9r]

first thing i'd check is the throttle cables.

you have one to open the throttle and one to close it.

if the closing cable is broken then only gravity can close the throttle!

[steer_rally]

Well, I've sprayed both WD40 and Easistart around the carbs and the intakes, with no change in engine speed, so am assuming that there are no air leaks.

It mostly happens when I'm riding, but does happen sometime if I try replicating the problem at standstill. If I blip the throttle, sometimes it takes quite a while to drop back to idle speed. When this happens, the throttle mechanism on the carbs seem to have return to the stops ok. I obviously can't check this while moving, but the throttle doesn't seem to be sticking or failing to return at all.

Also, there only seems to be one throttle cable, the one to open it. Looks like springs to make it close.

Anyway, thanks for the advice so far, I'll have another poke around tomorrow after work, see if I can find anything sticking.

[Guest]

you could try some carb cleaner, take out the air filter and spray it in through the hole, motor accessory shops sell the stuff..