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View Full Version : CV carb advice...I think



Willdat?
20th June 2011, 17:30
Some of you may remember my DR250 saga...anyhow I'm over that and enjoying learning bits and pieces of what makes my bike tick!
I've thrown a full rebuild kit at the Carb the only things not replaced are the diaphragm (slightly perished but intact) and the 'slide' spring. Needle jet on middle clip.

Symptoms
Idles well, bogs down under load.
if I hold the slide down (airbox off) I'm able to rev the bike out far more easily.

Another possibly (but I hope not) related issue is that the voltage across the battery at idle is 11V but it DROPS as the revs increases/ it bogs to ~ 6V.

Your thoughts much appreciated! I've just picked up off trademe another runnning (but not road legal) parts bike which I plan to chop and change parts with if no one has any ideas. Would be nice to have two runners!

Dodgyiti
21st June 2011, 08:14
In my experiences with CV carbs it is more often then not a problem with the diaphram than anything else. I have studied them after removing them with utmost care and attention and yet not found any dicernable issue with the rubber or any splits, cracks or pinholes. And yet popping in a new one sorts it.
It can be the pliability/flexability that can cause a problem rather than any visible damage.

Willdat?
21st June 2011, 15:40
Cheers, I'll see if I can source a new un'!

F5 Dave
25th June 2011, 03:05
try google Keyster carb kits, they may do diagphs

Willdat?
26th June 2011, 22:16
My Keyster kit didn't come with a diaphragm unfortunately...I have seen them for US$110 (just for the diaphragm). It's in the win lotto pile of purchases as the spares bike I bought came with two round slide Mikuni carbs that will do the trick.