VM28's, non-functional accel pump

good morning everyone.

the new engine i picked up came with some vm28 pumper carbs on it. seems to me that the pump is non-op.

i tore down the carbs the other day to clean the bowls, needle/seat assy's, and the pilot jets. i checked all the passages for the accel system, and they all appear to be clear.

at least i can move air thru them.

anyways, i get no fuel from the pump nozzles, and i am wondering if there is a way to pull those for cleaning without destroying them?

the other thing, i have NOT taken apart the pump assy to confirm that the diaphragm is intact. it's not leaking, so i decided it would be best to not pull it apart until i need to.

whaddaya all think?

--r

when mine didnt work the diaphram was rock hard. The kit isnt very expensive, I would check and replace it while you got em off.

Post edited by: zippoman, at: 2006/02/01 12:56

They will never work if the motorcycle sits for any length of time, even if the diaphram is fine and the nozzles are wide open. For some reason what happens is gas evaporates out of the diaphram area and never quite works it's way back there, so you're just pumping air. If you manually prime the diaphram with gas and pump the lever a few times to get gas initially squirting out of the nozzles all is fine until the next time the motorcycle sits and the diaphram drys again, then back to square one. This may not be your problem, but it happens every time I run either one of my KZ1000s as they sit a lot. I just don't use the accelerator pumps because it would mean removing the bank of carbs before each ride. This is my experience anyway.

Gas is picked up in the #2 bowl at the bottom within the small well (about 5-6mm wide) and goes through a passageway to a check valve. If the check valve is stuck or gummed up, you won't get fuel. There isn't any way to shoot compressed air into that well with a standard air gun (that I can think of) as the hole sits on the side of the well. I suggest trying to spray carb cleaner into the hole and it might free up the check valve. I have also taken apart the check valve by drilling out the cap over the top. If you do this, take care as there is a small ball and spring below and they will try and jump out and hide in a dark corner. It is possible to clean this area out and fab a new cover and JB Weld it in place.

does jeff sell the accel pump kit?

might be that the passage is goobered like george says. i picked a good amount of munge from down in there. if you can't get right at it, then that might be my problem.

chances are that the diaphragm is dry too. the carbs sat for ~10 months before i put gas in them last weekend.

i'll fiddle with them when i have some time. might get them to work, might not.

thanks for the pointers everyone!

--r

i found the accel pump kit on z1enterprises. 8^)

just need to know where to look.

--r