'broke' my carb

[Devon]

dooden@... wrote:

>Out = richer > >3 full turns seems excessive to me >

I used to think the same thing. Not all CVK-40 carbs are the same. I've used two different stock carbs on my A15. The one that came with it new returned 50mpg, and never needed the pilot mixture screw set much past 1 1/2 turns. I thought people who were setting their carbs to 2.5 ot 3 turns out were nuts. I swapped carbs wuth Tumu for the Alcan 5000 so he would have a carb that we knew was working OK. Never swapped back, so I'm using a '96 carb now. This has a lean surge at around 1/8 or 1/4 throttle (just past where the pilot screw has the most effect) that I can only cover up to a barely acceptable amount by lifting the needle and opening the pilot screw to 3 1/4 turns. I'm I have cleaned this carb every way I know how, including stripping it to the casting and dunking it, then blowing it out with compressed air. No change. There is either some sort of crud that defies solvents (and must be removed mechanically) or the carburetor was not manufactured properly. The CVK40 has five ports running off the pilot circuit- one is 1/4in "downstream" of the butterfly valve, that is the only one controlled by the pilot screw. The other four are arranged in a diamond shape that spans the bottom edge of the butterfly valve- At TINY throttle openings these would receive a vacuum signal in turn, and flow fuel. I guess as the last one starts to flow the slide is lifting and then you're on the main circuit. Anyway, it REALLY seems like some or all of the transfer ports are not properly flowing fuel. Or there is some obstruction in the passage above the pilot jet. The next act of desperation (I am REALLY annoyed with the poor running and crap gas mileage) is to take a fine metal wire and "explore" the transfer ports and the rest of the pilot circuit. Devon

[JRC]

> Anyway, it REALLY seems like some or all of the transfer ports are

not properly flowing fuel. Or there is some obstruction in the passage above the pilot jet. The next act of desperation (I am REALLY annoyed with the poor running and crap gas mileage) is to take a fine metal wire and "explore" the transfer ports and the rest of the pilot circuit.

> > Devon

The next thing I'm going to do is to put a few miles on it with fresh gas and Seafoam. Then, I may have to pull the carb and do as you suggest. If it comes to that, what is your recommendation on the easiest way to pull the carb? Thanks. Jim

[Devon]

jrc1515@... wrote:

>If it comes to that, what is your recommendation on the easiest way >to pull the carb? > >

Don't bother with the manual's procedure of pivoting the subframe. Remove the choke fitting and cable off the carb. Remove both throttle cables and all hoses. Drain the bowl (stick a small hose onto the drain nipple and turn out the 3mm allen a few turns). Remove the two hoseclamps entirely. Standing at the back of the bike, grab the carb on both sides and pull it back into the airbox boot until it just starts to clear the intake boot. Rotate it clockwise so the carb swings out to the right. As soon as it clears the intake boot you can wiggle it out the right side. Put it back the reverse way, making sure the bellmouth is seated completely in the airbox boot before you pull the carb back. Make sure you pull the carb back enough so you don't damage the intake boot. It will flex a good bit safely, but try to minimize this. Devon