CV-40 slide diaphragms

[smoserx1]

Today I replaced the slide diaphragm in my carburetor for the 5th time.  The first one lasted about 90000 miles and I replaced the entire vacuum piston assembly.  The replacement also went about 90K.  However the next one only lasted about 14K and the one after that about 10K.  All of them were Harley parts and the entire assembly now is about 50 dollars.  After I bought the 4th one I purchased just the diaphragm and fixed the third slide and put it away, and that is what I put in today.  I also ordered another diaphragm today and will fix the slide I just removed so I will have a spare.  Anybody have a clue why the last 2 failed so soon.  Ethanol maybe, or just bad luck?

[truck]

Old stock getting dry rot?

[klammer76]

I didn't know you could get the rubber diaphragm off and buy a new one from harley?

[FSG]

get them from Amazon   

https://tinyurl.com/yyyvldwu

[hdbikedoc]

carb body wearing maybe slide sticking and pressure plays havic with diaphragm   Bob Yost always said the carbs were worn out at 100.000 and should be replaced

[Hossamania]

carb body wearing maybe slide sticking and pressure plays havic with diaphragm   Bob Yost always said the carbs were worn out at 100.000 and should be replaced

I'm coming due for a new cv44 then, surprisingly still available, it seems.

[koko3052]

As the above have stated...old stock, wear in the body....
For shits & giggles, I would try polishing the body with VERY fine compound just to see if that will make any difference. Report back please in a couple of years....or sooner if you have found a rough surface.
None of us carb lovers are getting any younger.

[hdbikedoc]

I have a few new put away just encase   

[smoserx1]

Thanx for the responses.  As long as I can get a diaphragm for less than 20 dollars I am not getting a new carburetor.  Swapping out the slide assembly is an easy procedure.  I have been running an N65C (old Sportster) needle.  I replaced it with a NOKK needle I bought about 10 years ago but never installed.  Seems to run real good on this needle...I am curious if the MPG will change.  FWIW I looked on ebay and amazon for a CV-40 and there a plethora of new el-cheapos there (ZOOM-ZOOM, Carbpro, etc), some with mixed reviews.  That surprises me, since the carburetors have been phased out  for quite some now, that you would have a large supply of (probably Chinese) knockoffs coming in.  I will let you all know if this new diaphragm fails anytime soon.  Thanks.

[klammer76]

get them from Amazon   

https://tinyurl.com/yyyvldwu

Thanks Gary.

[trex]

https://cv-performance.com/  Can get everything you need from this place

[Julio]

Any parts you can't get from CV performance, you can get from your Kawasaki dealer.
The CVK40 used on KLR650s from '88-'18 uses most of the same pieces as the HD CVs, except for the  pump. The CVKs, like the first HD CV, has no accelerator pump.
Slides, diaphragm, needle seats, enrichner plunger, and best of all, the early CV round floats are all available and ethanol resistant now.

https://www.kawasaki.com/Parts/PartsDiagram/206574/2018/KL650EJS

[smoserx1]

Hey Julio, thanks for that link.  Interesting thing about the Kaw carb is the air cut valve (the thing that looks like an accel pump) on the side.  For anyone who doesn't know that valve shuts off the idle circuit during head deceleration and eliminates the popping in the mufflers.  My old gold wing had one on every carburetor and I had to replace all of them at one time $$.  Nice idea but if it fails, guess  what?  Your bike quits idling.  I had always heard the Kaw carb had one...now I see.

[Julio]

Hey Julio, thanks for that link.  Interesting thing about the Kaw carb is the air cut valve (the thing that looks like an accel pump) on the side.  For anyone who doesn't know that valve shuts off the idle circuit during head deceleration and eliminates the popping in the mufflers.  My old gold wing had one on every carburetor and I had to replace all of them at one time $$.  Nice idea but if it fails, guess  what?  Your bike quits idling.  I had always heard the Kaw carb had one...now I see.

That's good info on the air cutoff valve. I'll keep that in mind if my KLR starts acting up.

[Ohio HD]

FYI on the Kawasaki parts, I used to order them from a lawn & tractor business near me. As long as you have the Kawasaki part numbers, they can order them.