Can't rev with or without choke and backfiring

[bob706]

pin-sol works like a champ though

[ducatiman]

I REFURB a set in approx 5 hours start to finish.....waiting on a overnight or 24 hour dunk process? No way...too slow....(yet admittedly the next step better than spray can and toothbrush) but can't even remotely compete with the ruthlessly efficient modern machines.

[ducatiman]

Originally Posted by Triple Jim

I'm very interested hearing about the aftermarket diaphragms if you do investigate them, Gordon.

I didn't forget or mean to disregard you...just busy.

Long ago researched another aftermarket slide rubber. I stock them...however *very* tricky to install, major surgery required.(I've ruined a slide or 2 in attempts) ...I do for $100 per pair parts and labor (doing both suggested to retain equal slide "action" between carbs)

And still beats the factory replacement price.

Requiring both rubber replacement and carb refurb understandably exceeds my selling price of already done, stocked REFURBS...hence Brads choice of simply buying the stocked set. Quickest, cheapest option under the circumstances.

Regarding the ebay replacements posted yesterday...forget about stretching to remove the stock rubbers ...no way. I tried yesterday, couldn't remove. I wouldn't be too quick to buy from the Eastern European vendor....the other listing was simply the wrong diameter... got to be rather disappointing for those ordering and anticipating easy repair.

[Triple Jim]

Thanks Gordon. The seller did say in the description that replacing the diaphragms was not easy.

[ducatiman]

Its been my experience on the 250... rubber removal entails the top plastic retainer to be removed, I believe the factory uses an adhesive to seal it to the valve body...thus both capturing and sealing the rubber. Choose your weapon... knife, dremel, whatever...requiring cracking it off, removing the retainer piece by piece. On the underside a thin shelf....part of the plastic slide...be too aggressive and you break that....therein the difficulty. Can't be too aggressive, or not aggressive enough...tricky...one slip, she's broke.

Compounding the problem, the factory never designed rubber removal from the getgo...only complete slide replacement... as an assembly.

The EX500 actually offers easier rubber replacement... uses a similar plastic retainer over the *metal* slide body....the lower "shelf" won't break.. Always a set in stock here for the 500

[ducatiman]

Success....spent a couple of hours tonight on slide diaphragm replacements.

Spent about an hour on extricating the plastic retainer on the first one. Got my methods together...2nd one took just 10 minutes.

Used soft plastic jaws in my vice to carefully hold the slide body...2 hands needed to cut slotted segments into (via dremel) then tap out (basically breaking off) the glued retainer... piece by piece....carefully avoiding peripheral damage. Surgery for sure.

Once retainer is off its downhill from there....the remnants of the old rubber easily pulls off.

Carefully seat the new diaphragm (make sure its installed right side up!) ....adhesive of your choice to both seal and hold.

It can certainly be done... def a major nail biter...I would only suggest this for experienced folks with the right tools. Darn tricky.

In the pic the piece on the left is the remnants of rubber...segmented pieces on right the plastic retainer.

[Ghostt]

You gave a gun to a kitten LoL

[ducatiman]

i'd urge kitty to be super careful or better yet ...not get involved at all.

[Triple Jim]

So you glued the new ones on and didn't use a retainer? Or do new retainers come with the diaphragms?

[ducatiman]

the center section (called the "tire") is thicker...compensates for and renders retainer unnecessary

I've used them before (without issue) in both 250 and 500.

Reordering another set for stock for both machines.

[Ghostt]

I'm sorry I couldn't help myself, but on a serious note that's good news for those whom need them, has to be cheaper than OEM

[Triple Jim]

Very interesting, thanks again. I recently got some Bob Smith IC-2000 cyanoacrylate adhesive. It's supposed to have some flexibility when cured. I used it to bond some Viton to aluminum reed cages and it's holding well. Do you have a preferred adhesive to a job like this diaphragm?

A friend recently got some 2-part industrial adhesive that's actually Viton when cured, made to bond Viton among other things. That could work great for this application, but it's really industrial, so you have to talk your way into a free sample of about a quart of this stuff, or pay hundreds of dollars for gallons.

Are the correct diaphragms the ones that were the first link in JacRyann's post? (link now deleted)

[ducatiman]

a CA gel type, i think, the rubber and plastic will literally melt into one another and create an airtight seal.
A quality RTV would likely work...may be other choices, gotta looksee what I've got and choose.

*edit...CA specifically recommended...RTV dissuaded

The 2 part you mention sounds interesting...the quart = lifetime supply

Possibly, can't remember now...though the (2nd link?) one at 67mm is absolutely wrong for 250.

How many slides you fixin' on doing?

[Triple Jim]

No definite plans. When I had them apart, I slightly tore one near the edge. As I remember, it was stuck partly to one side and partly to the other, and even though I carefully tried to peel it loose, I made a very small tear. I used some industrial polyurethane adhesive to patch it and it's been working fine. If I have to take it apart again, I'd like to have a new diaphragm in my hand in case something goes wrong.

Or (as I've brought up before) I may be a pioneer and see what happens with a couple spare VM30s I have sitting around.

[VioletGibson]

If you can get your hands on it, the medical CA glues have more akyl-groups in the formulae. This makes it more flexible when cured. Might be useful.

What's the diaphragm material on this bikes? I remember taking some apart on Hondas way back when and it was some sort of fabric impregnated and coated with rubber. Very flexible yet not very stretchable.

[ducatiman]

your first post, welcome Violet Gibson (guitar player?)

OEM is rubber....no fabric ....I don't recall any fabric being used in a CV (motorcycle) diaphragm application.

Ones I'm using are the vendors own rubber composition, high fuel, ethanol and chemical resistance, heat, temp, blah blah. They are thicker, feel different...its recommended changing both (in a twin) all 4 (in a I-4) to retain lift characteristics within cylinders.

**********************************************************

On a related aside ...folks spraying starting fluid and carb cleaners in assembled carbs gives me the heebie jeebie's....a real quick, efficient way to chemically distort, weaken and destroy your rubber diaphragms, intake manifolds, airboots. GET TO THE SOURCE of the problem..what diagnostic benefit is a quick run on ether supposed to prove? And in the end, you still must get to the root carb problem anyways. Cut to the chase, diagnose and FIX...don't use these destructive sprays in assembled carbs!