random varying of idle???

[mcollett]

The idle speed on my l2 varies randomly, if i pull up at a set of lights it idles at 2200-3000 rpm, if the then rev the balls of it, whilst stationary the idle drops to 1200-1500 and slowly creeps up to 2200 . The bike's had a new fuel filter, new spark plugs, carbs have been balanced within the last 1000 miles, did notice when balancing the carbs a small movement, ie pushing the carbs up/down, changed the idle speed. Is it likely to be the carb holders? I also get a some white smoke out of the end can when i start the bike from cold, this then disapears when the bike comes up to temperature, is this normal? could it be related?
Thanks for any help.

[CaNsA]

Carb rubbers are leaking.

Spray some wd40 on them while the bike is running, if the revs change then you have a leak.

[mcollett]

ok second question, obviously i need to buy new seals, the part diagram on kwaks websites show 2 carb holders for my year, HOLDER-CARBURETOR - 160651240 AND HOLDER-CARBURETOR - 160651176. In the diagram they appear to be diffrent, do i need both parts do you think?

[CaNsA]

16065-1240

[mcollett]

Ok thank you for the help, parts ordered with cradley, will endeavour to change them soon, and will rebalance after.

[CaNsA]

I hope you got your ZXRworld 10% discount.....

[mcollett]

we get a discount? i ordered online?

[cargo]

If your lucky you'll get a free pen

[KwakKwak]

Not lucky, special.

[mcollett]

ok, much delayed response.
had the carbs off... changed rubbers, re-balanced, still doing it... cleaned the carbs with carb cleaner.. didn't disassemble.
could it be the throttle body sticking somewhere? if so any clues as to where?
If it helps the choke doesn't hold itself on, it will stay for a few seconds (normally enough to get half a glove on) then drop of again.

[Class1]

ok, much delayed response.
had the carbs off... changed rubbers, re-balanced, still doing it... cleaned the carbs with carb cleaner.. didn't disassemble.
could it be the throttle body sticking somewhere? if so any clues as to where?
If it helps the choke doesn't hold itself on, it will stay for a few seconds (normally enough to get half a glove on) then drop of again.

This could be a float valve/o ring or seat problem, where the fuel is building up in the mixture chamber at low engine speed, then all gets sucked into the comb chamber when the butterfly is opened. May only be one, but would recommend a repair kit on all four. This would explain the white smoke from cold where the fuel is leaking into the chamber while idle, then it running very rich at the initial start up; when the engine is hot and you switch it off, can you hear an intermittent hissing sound like a steam iron coming from the carb or carbs? If so, this is fuel building up behind the butterfly then seeping into the manifold. Other than that, check your diaphragms.