I've posted this question in the General Forum and it was suggested I ask it here. I've got an 85' EVO bagger that I changed from a butterfly to CV, some years ago. Started it about two weeks back and noticed that above 2000 rpm, fuel was coming out of the accelerator nozzle when I kept the throttle at a steady rpm. No problem, I've got two other CV's on the shelf, so I installed one of my backups. Same thing happened. So I installed the third, again the same thing. So I completely stripped down the carbs, using carb cleaner and air compressor, all carbs were spotless. Reassembled all three, set the floats, changed all seal and gaskets, and reassembled. All three are jetted the same, 45 slow, 170 main, Sportster needle. Mounted a clean carb with the same results. Tried alternate fuel bowls on different carbs, same results. I removed all the nozzles from each carb with it's corresponding metal needle, to be sure that nothing was stuck, same results. Added small brass rod for extra weight to the accelerator needle, same results. I ordered and am waiting for a ball, spring and new nozzle from J&P. Have new fuel line, CVP brass fuel inlets, and petcock. Has anyone experienced this, or perhaps noticed it when checking out your carb? Need advice.

 

The accelerator pump should only squirt fuel only on throttle roll on and not afterwards, this is accomplished by the push rod on the bottom of the throttle cable connect. There is also a check-valve in the accelerator pump that should be in place, check to see if it is still there. Check the accelerator pump diaphragm as well, verify that it is in the right direction.

 

Not to be disrespectful, but did you read the entire post? All gaskets and seals replaced(that would include the diaphragm which has a lip that mounts only one way into the float bowl groove with the spring in the pump cover), remounted nozzle after cleaning with check weight/needle side down(the same way it came out).

 

Received my new nozzle, ball and spring for J&P this past Monday. I tried all combinations and found one that worked for me. I didn't use the spring since it exerts too much down force holding the ball or needle in the seat and immovable causing all the fuel to exit the input fuel port inside the bowl. So I drilled out the accelerator nozzle cylinder with an 11/64's drill all the way to the bottom hole or port, enlarging it slightly. Dropped in the original three sided needle, point down. On top of that, I put the ball(no spring). Installed the new nozzle, clocking it correctly. Installed the fuel bowl on the carb. Started, idled, and warmed up the engine, and now for the test. The new accelerator nozzle atomized the fuel spray to more of a fog then a stream, engine accelerated fine. Now to test if the fuel would leach from the nozzle when the throttle was held at a constant speed or rpm. From idle to 2000 rpm, no leaching, just an initial fog to add fuel from idle, but when held at 2000 rpm, no leaching. Back to idle then to 3000 rpm and hold. Again no leaching. Back to idle, then to 4000 rpm. No leaching at a steady 4000 rpm. One last thing, you must remove/grind/file off the lip from the new nozzle. The lip interferes with the rubber bowl gasket and prevents it from sealing properly. In other words mine leaked fuel with the lip. In my opinion, the lip is not needed and seems to be an unnecessary feature. Notice the OE nozzle has no lip, just a step up from the cylinder bore size to the external overlap which is sealed with the bowl gasket. It worked for me, no guarantee that it'll work for you, but at least maybe it'll help some else.

 

Thanks for posting a follow up and your fix. It sounds like lots of trial and error...

Again, glad you got it fixed. YD

 

Yankee Dog, I just could never walk away from a problem, been wrenchin' for too many years.