CV Carburetor problem

[joeyc004]

So I have a 92 883 sporster with the cv carb.......took it off cleaned everything....put it back on idles great. but when u rev it up the vaccuum piston hesitates and wont slide up fast enough causing the bike to die out. When you hold the piston up its runs fine but not on its own. My question is whats causing this problem, why was it working fine before?

 

[Bud White]

did you tear the diaphram to the piston ..

 

[joeyc004]

well see thats the thing i did not see any visual tears.......could there be one so small and i cant see it?

 

[HDDon]

Either a tear, or you pinched it when you put the top back on.

 

[Bud White]

possibley is it curling or is it fitting flat at the sealing surfaces ?

 

[joeyc004]

no it was bigger like it expanded then the seal seat but i did get it to fit, so pretty much that is the problem or there anything else i could try before i go and get a new one

 

[Chopper]

I would take the top off and inspect the rubber diaphram again and if there are not any tears put it back together carefully making sure it is seated in the grove all the way around and then you should be able to move the piston up with your finger and feel pressue if it's seated properly. If it's not torn you do not need to replace it.

 

[NEWHD74FAN]

Sounds like the diaphram was distorted and not centered and seated when cover was lowered on (spring should be rotated so it fits square and centered in groove as well) when reassembled). With the long tapered needle below cocked slightly, it will bind as it pulls up...

http://www.hdtimeline.com/fuel_and_carb_related_issues/764-twin_cam_cv_carb_rejet_suggestions.html

 

[joeyc004]

thanks for everyones help i just replaced the vaccuum piston and its running perfect thanks

 

[BUBBIE]

thanks for everyones help i just replaced the vaccuum piston and its running perfect thanks

JUST READING THE OTHERS POSTING HERE.......

WE ALL MUST HAVE HAD THIS PROBLEM ONE TIME OR ANOTHER..

For me the PINCH was the USUAL problem and what a BUGGER to get it right..

Then get the pinch out and a section wasn't in the correct position to seal...

The LUCKY and PATIENT few who get it RIGHT the first time....
Pheeeeeeeew! ..... Glad it is together and working!

signed....BUBBIE