Diaphram rubber shrinkage?

[corgitwo]

Bought complete rebuild kits for my 79 xs1100f. When reassembling, I noticed the diaphram rubber under the top cover has shrunk slightly. Can't get it to stay in place while I put spring and top cover on.
Is there an adhesive or sticky grease I can use to keep it in the groove during reassembly?

[DiverRay]

I use just a LITTLE of the "non hardening" yamabond on about 4 points. it's just so you can hold it in place, but still remove it later without damage.

[oldnortonrider]

When I last did this, I had the same problem, particularly on two of the carbs. I was really frustrated, trying to figure how to make it work. Finally, I got a jar of Vaseline, and applied copious amounts all way 'round, pressing contact area of the rubber (diaphragm) all way 'round. Wouldn't hold for long; had to get the "lid" on quick.

[dbeardslee]

Oldnorton - vaseline and rubber don't get along well - it makes rubber deteriorate. That's why your never supposed to use it with the other kind of rubber - fewer unwanted pregnancies that way .

[wa407mpp]

Try putting them in the frige for a while, getting them cold has always worked for me, but mine always seamed to expand after being removed from the carbs.

[Trainzz]

Vaseline

I was gonna make a smart answer to the Vaseline comment, but remembering that I am gonna be in Hurst next month.................well let's just say I don't want to give Kat (and my wife) any ammo.

Gawd, sometimes I am a sniveley little worm.

[oldnortonrider]

Oldnorton - vaseline and rubber don't get along well - it makes rubber deteriorate. That's why your never supposed to use it with the other kind of rubber - fewer unwanted pregnancies that way .

............right; the Vaseline is a petroleum base. When I did this, my thinking was that the diaphragm, being where it's at, would have to be exposed to gas vapors, fog, fumes, i.e. all kinds of rigorous "petroleum" contact. Sooooo, I was thinking this diaphragm must not be 'rubber' material. (??) And, I was thinking "whatever" it is made of~~it likes petroleum......(???)

[dbeardslee]

Fuel line is rubberized and will handle gas too, but it's made out of different material than oil lines. Point being just because it stands up to gas vapors, doesn't mean it's going to stand up to vaseline. At $65 a pop for new diaphrams I wouldn't take the chance. My $.02

[cywelchjr]

Fuel line is rubberized and will handle gas too, but it's made out of different material than oil lines. Point being just because it stands up to gas vapors, doesn't mean it's going to stand up to vaseline. At $65 a pop for new diaphrams I wouldn't take the chance. My $.02

Actually a lot of write-ups on working with the diaprams on CV carbs suggest grease to hold them in place while getting the cover on. I can't see vaseline being worse on the rubber than gasoline or regular grease.

[dbeardslee]

There are different kinds of grease as well, and the material I've seen suggest that silicone based grease would be a safer bet. Here's some material on rubber o-rings, but the principle should be the same. Now all we have to do is find out what the diaphrams are made of...

[TopCatGr58]

With all of this talk of rubbers, and diaphragms, and vaseline!!

Perhaps most of you folks are too young to be "intimately" familiar with this other product , but there's a water based LUBE called K-Y jelly, safe for all sorts of RUBBER products!

However, a technique that I've used is to put the slide/diaphragm in place as best I could, put the spring and then top cap on but turn it 45 degrees off position from where the screws line up, and you can slide it around off center to check and reposition the diaphragm as necessary, keeping the cap down tight enough to keep the rim down in the groove, until you're sure it's secured and flat, and then position for the screws, and put 2 opposing corners in finger tight first, and then the other 2. JAT.
T.C.

[skids]

Yup. It is Friday. That is quit Freudian. TC probably has the infamous towel ready.

With all of this talk of rubbers, and diaphragms, and vaseline!!

Perhaps most of you folks are too young to be "intimately" familiar with this other product , but there's a water based LUBE called K-Y jelly, safe for all sorts of RUBBER products!

However, a technique that I've used is to put the slide/diaphragm in place as best I could, put the spring and then top cap on but turn it 45 degrees off position from where the screws line up, and you can slide it around off center to check and reposition the diaphragm as necessary, keeping the cap down tight enough to keep the rim down in the groove, until you're sure it's secured and flat, and then position for the screws, and put 2 opposing corners in finger tight first, and then the other 2. JAT.
T.C.

[Ken Talbot]

Try putting them in the frige for a while, getting them cold has always worked for me,

Say what? ;-)

[81xsproject]

I have experienced this on just about every set of carbs I have rebuilt. After trying many things; adhesives, etc. I found that if you fit then to the carbs where they go and use many fingers to hold it in place, after a minute or two, it will stay put long enough to quickly put the covers on.

[wa407mpp]

I thought I said it all, but I'll try again. If the diaphrams haven't been out before they can be set in the groves pretty tight and will stretch just a little when removed, so that on reassembly they won't lay in the grove evenly making it hard to put the cover on without pinching the rubber. so if you freeze them a while 30 min. to an hour they will shrink down enough to fit in the grove better so you can get the cover back on with pinching diaphram.