Spitting carbs...

[TomRodgers]

What causes carbs to "spit" or "cough" back through the air filters (pod filters) when engine is cold??

[bikerphil]

It is probably not getting enough fuel. If it does that with the enricher circuit (choke) on, the passages might be clogged. Cold engine requires a bit more fuel to operate.

[TomRodgers]

kinda what i figured....once it warms up, no problems.

thanks...just kinda made me question it, when white vapor blew out the airfilter.....

[boyat68]

TomRodgers:

It also could mean that your carbs are flooding, fuel not cutting off by the floats or the needle valve. When the bike is hot and using all of the fuel presented to it by the carbs, it may not show. If you have a shut off valve, then it may not show until you try to start the bike and the excess runs out of the back of the carbs. One way to tell is turn the fuel on to run and let set for a length of time ad take off the lower air filter and see if the air boot or throat of the carb is wet. If it is then carb fuel adjustment is in order.

[tarzan]

Just curious,is it backfiring with the enricher on the 2nd ntch(full choke)
at idle.Cause if your trying to rev it up cold even with the enricher, on it can still be too lean at first.I let mine warm up for a minute or so,then its fine.

[TomRodgers]

No backfiring when idling....just the "cough" when cold...

after a minute or so of "fussing" it idles smooth and steady at 1000-1200 rpms.

no wet filter boots at any time....

also noted that after installing the 4-1 exhaust, now when revving...it gets an extremely loud "crack" or "pop" on the declining rpms...I never noticed it on my other bikes, just on this one...

[trbig]

Between pod filters and a 4-1 exhaust, if you haven't re-jetted your carbs, you are going to be running pretty lean. Even if you have re-jetted.. popping on decel indicates a lean condition.


Tod

[Korr]

It's been cold in the mornings for me here in Union City CA and the bike is making a pfft! sound when the choke is on during warm up. It does that every 15-20 seconds.Even when the bike is warmed up. It still does it if the choke is on. The rpms will drop everytime it does that. I'll do what Tom said and see if they are wet.

[randy]

Back-coughing can also be caused by out-of-synch carbs.

[Korr]

I FINALLY got around to checking it out and found out that it was a loose nipple!!!