running ruff at low rpm.

i am the proud owner of a 1984 zn1100 ltd the bike ran great then i had to take it down to hav ethe tank painted. after that it ran terrible. i pulled the carbs and they were real nasty.ihave cleaned my carbs and put new carb holders on

now the bike runs good at high rpm but sputters at low. no problen starting it just chugs until it get revved up. any suggestions

thanks b parker

When you took the tank to the painter, had you left the petcock on the tank?

Good chance it's partially clogged.... Not sure on your bike, but other KZ petcocks, the portion that resides in the tank internally, there is a filter attached. Drain your tank, remove petcock and clean if necessary.

Do you have an inline fuel filter from tank to carbs, how does it look? Replace....

OMR

If you left your petcock on the tank it could be a paint chip worked it's way to your carb bowl if the fitting was painted or maybe your gas line had some dirt on it or rust got in it when you reinstalled the tank. This is indicative of your secondary jets being OK at fast idle but the primary or pilot jet (low idle) is clogged.

I don't know if you have a 2 or 4 banger, but if it's a 2 cylinder you have a 50/50 chance of guessing the correct carb jet that is clogged. If your petcock doesn't have an OFF setting,chances are it is a vacuum operated gas valve and you can open the bowl drain, inspect the fuel in a glass container and see if there are any contaminates in it. Chances are, if you had a clog there are more particles just waiting for their turn. If it's really contaminated you may have to drop the bowl and clean it out. If only one bowl is contaminated,(yeah, right),then you've got your culprit.

Does your bike have a lot of room around the carb? You may have to drop the bowl to inspect the jet and clear it. Better done if you have rubber type gaskets and not paper/cardboard which may require replacement after removal. Keihin carbs typically use rubber. Mikuni like to use paper. If you don't have enough room to work on it you may have to take it off to inspect it. Are you comfortable working on a carb? Even so you may want to get the owner's service manual if you don't have it already.

If by looking at it, you don't know which jet to look at the general rule is the low idle jet is closest to the engine. If, and only if, you have to move the associated needle make sure you take note of the screw head position, document it, and count the revolutions so you will know where the adjustment is at during assembly. Luckily it will only be the jet that needs cleared.