Choke travelling , as in opening and closing fully ????

Sounds closed.......... they always need choke to fire up

Might not be reconnected properly

 

would the choke cause the drop in mileage?

 

sounds like my first check.

Thanks

 

Remember automobile carburetors that had a butterfly valve at the top that would close and choke off the air supply to make the mixture rich? If it stuck closed or partly closed, the car ran rich and wasted fuel.

The CBR's Keihin choke doesn't work that way. Opening the choke lever allows (lower?) air pressure inside the upper chamber of the carbs to raise the piston/needle out of the main jet. That richens the mixture making quick starting. Closing the choke lever allows less air into the upper chamber, lowering the needle, and lowering the idle speed.

The problem is that one or more of the piston/needles can hang up in a dirty bore. They usually hang up in the fully open position, or close very slowly so the engine runs very rich. I think this is the most common carb problem. The tops of the carbs have to come off and the pistons and walls have to be cleaned. See the "How To" section.

The first time cleaning them is kind of strange. But you will see the ingenious way the needle comes out of the main jet, and the ingenious way the choke works. With the carbs completely clean, you will be amazed at the way the bike responds to the throttle.

 

Excellent info Slowp. Thanks.

 

Ok looks like slowpoke is the winner. i checked the choke and it is opening fully no problem. Since the carbs were just pulled and cleaned i don't think i should be having this problem. i guess i will be calling the mechanic back, hate to have to go back

 

spoke with the mechanic and he thinks it is just finally getting the gas it wanted.. the carbs were very varnished he said. he did not change the jets or timing so he said he is at a loss for what might be the problem. His gauges said it was running fine when he gave it back, but he will look at it again. getting a funny feeling about this, but not much choice at this point. will drop it off later this week and see what he comes up with.