Source for carb diaphragms

[LAB3]

Seems to me I was under the impression that diaphragms for "Mick Cooney" carbs where unavailable. Has anyone had any experience with this supplier: http://jbmindustries.com/index.html

[sam000lee]

I've never used JBM but in all my searching are the only source for replacement BS34 diaphragms. I've heard of other people using them. If you go for it, I'd be curious to know how they work out.

[suzukizone]

Hi LAB3, I'm looking at these as well. Did you get them? If so how'd it work?

Do you know what they mean by"roll" the diaphragm??

Thanks,
DH

[LAB3]

Haven't bought them yet, probably have several more weeks before I take the bike off the road for the winter. As to rolling, there's a good many pictures and instructions on that site, anything other than that would be speculation and I would hate to have you rip your new ones by giving an uninformed guess.

[suzukizone]

Haven't bought them yet, probably have several more weeks before I take the bike off the road for the winter. As to rolling, there's a good many pictures and instructions on that site, anything other than that would be speculation and I would hate to have you rip your new ones by giving an uninformed guess.

Thanks LAB3. JBM sent me this:

"Best way to describe rolling is with pictures...

http://www.jbmindustries.com/HITACHI.html

It refers to the process of having waves in the diaphragm to make it flat."

Guess I'm dumb here. Wish the vid said, "This is what JBM means by rolling." But he didn't and the statement about having waves makes me think I should take it down to the ocean and throw them in first. Waves make it flat??? Are they saying to roll the outer edge to make the piece sit flat in the groove in carb body? Are you supposed to roll the diaphragm in your hands to "loosen" it up before assembly?? Just wish there was an actual video/image to clearly show this if so important. Unless I missed something while watching.

For all their statements about the importance of this, & including the process as not something to miss in the FAQ about what you can do wrong, I'd love to see it just a bit clearer.

Anyways. I think this item would be a good thing for my GS850 but not sure if that in itself would cure the running issues she has developed. Will attempt to clarify the term "roll" while enjoying a bagel.

DH

[LAB3]

My diaphragms are still in tact as far as I can tell but as with anything that's 36+ yrs old and made of rubber it's just a matter of time before they give out. Having just completed nearly five months on the road and shooting for six or more next year I'm hoping to be able to keep from getting stuck somewhere waiting for a part or having to pay full retail for the same thing I can order somewhere else for half the price.

[gustovh]

Rolling the diaphragm seems pretty simple to me. The arrow points to the roll, what the diaphragm should look like when installed, the finger points to the roll. The tire is the thick rubber of the hole for the slide.



V

[suzukizone]

Rolling the diaphragm seems pretty simple to me. The arrow points to the roll, what the diaphragm should look like when installed, the finger points to the roll. The tire is the thick rubber of the hole for the slide.



V

Thanks gustovh. The trouble I was having in understanding was this.

did "roll" mean the verb and some method of actually rolling the material of the rubber diaphragm to, I don't know,...soften it up or did it mean rolling the outer edge and the "tire" that fits into the groove of the metal slide or some other action involving manipulating actively the rubber. Or, did it mean, as you see it, just seating the diaphragm such that there is a roll as in the picture. Kinda like is roll a verb or a noun?
Your answer sort of makes a lot more sense so If & When I get these, I promise not to roll them around waiting for some miracle transformation.

Thanks for you getting back to me on this.

DH

[derwood]

I used them on my old Kawasaki. they were easy to install.
I had to cut the old ones off and the plastic retainer.
the JBM ones were a lot thicker around the hole, they came with instructions and they worked just fine.

[suzukizone]

Hi, after a long delay, I installed my first JMB Diaphragm on #1 carb.

Easy to cut the upper & lower plastic retainers,....even I could do it.

Cleaned up the groove in the top of the slide with carb clean & Nylon parts brush. The outer top edge of the slide was a bit rough so I got a very fine file and with the utmost gentlemanly strokes I lightly took most of the roughness off. This was done with the utmost care so as not to take off any metal save the worst of the "burrs".

Noting that the pinhole in the bottom of the slide faces forward toward the engine I put a red dot to mark that position and aligned that dot properly with the carb's orientation. I made note of the "dip" in the upper carb surface where the old diaphragm fit in and used a marking on the top of the new diaphragm as a pointer.

The new diaphragm slipped on with minimal effort and can be rotated within the groove to get all aligned as needed. I then put a small drop of red nail polish to show where to set up for future hoodledoodling with slides.

The only issue I see is that these are much thicker than the OEM diaphragms and a bit stiff and not lying true as to the "roll". I had mentioned this to JMB in email & was told to lightly warm with a hair dryer & they will cooperate and look as nice as in the pics on the JMB site.

Got late had to stop,more to follow.

Main point, If an idiot like me can get this far successfully anyone should be able to do it like a pro.

I remain,

DH

[Greg B]

Sure looks easier than the hoops I jumped through.
Wish I had known about about it then.
https://www.thegsresources.com/_foru...nt-oh-what-fun!

[suzukizone]

Sure looks easier than the hoops I jumped through.
Wish I had known about about it then.
https://www.thegsresources.com/_foru...nt-oh-what-fun!

Hi Greg, WOW! Some project. Don't know when JMB started making these in general & the ones that fit my carbs in particular. Perhaps with your fantastic skill set you could build a "way back machine" or a flux capacitor for your DeLorean and bring a set of the JMB diaphragms back to 2010 to figure the easier way out. But maybe you would decide it was more fun to use your elegant equipment and abilities to go your own way.

Very impressed I must say. I would take my hat off to you but every time I do that I put it down somewhere and can't find it.

DH