Rubber diaphrams and silicon ...

It would seem that the rubber diaphragms and some sort of silicon lubricant would be a match made in heaven. Wipe the rubber with the silicone and you have a nice protective layer to preserve the rubber.

What am I missing?

 

Before all the neat stuff that got invented to maintain and repair Rubber Diaphragms ... you raided an Audiophiles Cabinet for some of the "Good Stuff" they had to keep the Rubber Pinch Rollers supple and not sticky.

"TEAC" Rubber Roller Conditioner.

Now, there's loads of good stuff.

 

Yes Rick,
But that really doesn't answer the question if silicon lube would be a good thing to apply to the piston diaphrams in the carbs.

Mike

 

thats what i use on mine but consider the silicon just about rules out ever using any glue on them

 

Sometime I am going to have to take a dead piston apart. There has to be a way to be able to replace that rubber. They got it on in the first place ...

 

look up ebay seller "motoallparts" if you have a 900 or 1100 your in luck

 

59 bucks for a set of 4, you got to get them, even if you don't need them.

 

I hope silicone lub is ok hehe.. I used it at my job in the Dental/medical Equipment for 8 years. It is the only lube most manufacturers recommend for there O-rings and seals. Thats what I put on mine last time I had them apart. Out of curiosity Polock why would you want ot glue them?? the sil Lube is plenty sticky for hte top lip to stay in place upon reassembly.

 

Glue = to seal holes, pinholes etc.

If they are super-lubed... the glue spray or what not won't stick.

 

On two of my slides the top clip that keeps the diaphragms on the piston is broken. They still hold the dia decently, and it seems like I could get them off and back on, but right now I don't want to find out that I can't for $139.

 

There's always these guys!

http://www.motorcyclecarbs.com/_P15676.cfm

 

RTV since it stays flexible I can see If thats what was meant by glue then offense meant, glue to me means a hard setting substance made not to move.

 

The original retainer rings that cinch the diapgram in place are assembled onto an un-swedged piston, and then the top of the aluminum piston is crashed to lock the lower ring, diaphram, and upper ring in place.

Mikuni did a great job of crushing the thin top lip of the piston (or, they used a better plastic upper ring material), because you almost never see a Mikuni vacuum piston with a cracked upper retainer ring.

Hitachi piston's, on the other hand, you rarely see a unit WITHOUT a split upper ring...and sometimes it's just a split, and sometimes they're grand-canyon sized splits.........

And that also includes splits on brand new, still-in-the-wrapper ones, too.


Replacing the diaphram is an interesting challenge, since once the piston is swedged, there is no "un-swedging" that's going to happen, and that's the only way to remove the top ring without destroying it (of course, on a Hitachi, with a fully split upper ring, you can actually snake them off, for whatever that is worth!).

I've tried to replace diaphrams on the Mikuni's before, and if you huff and puff and grunt and hold your tongue just right, it can kinda-sorta be done almost successfully, although it's questionable whether you actually really get the thin inner-diameter "ring" that's on the diaphram to really, REALLY seat into the recess on the retaining ring........and without it seating, then you have an upper side-to-lower side vacuum leak, which defeats the whole purpose of replacing the diaphram, etc.


We've looked at a number of different ways of creating an in-the-field replacement upper cinch ring mechanism for these piston units, and they all seem to have some type of failure quotient or incredible expense built into them.

By the way, the magic goop (rubber lubricant and rejuvenator fluid) is carried as part HCP8540 RnR Fluid, works fine. The original TEAC brand pinch-roller fluid is no longer produced by them.........

 

I have Repaired holes and chaffing-style leaks using Liquid Electrical Tape.

First. Cut the "Dabber Brush" off of the Bottle Cap and get rid of it.

You need

A FORM.
Cut the Neck off a Small Funnel so the Piston Body fits in the Narrow end.
Spread the Rubber out and use masking tape to keep it from moving.

Pour a little bit of the Liquid Electrical Tape and use an Artists Brush to apply the RAPIDLY DRYING PRODUCT on to the Diaphragm.
Once the Product starts to "Pull" and Dry-out ... don't use it.
Pour-out fresh product.
Use the Cheap Artist Brush KIT that has a dozen brushes for $3.99
You don't have time to clean a Brush
Grab a fresh one.

Fresh product, fresh brush, cover the area, let dry.
Do BOTH Sides of the Diaphragm
Two coats; minimum.

 

Provide your old piston, 1 month turn around (maybe), please *prepay* with check or money order (we don't like credit cards since you can dispute the charges when we fail to satisfy), "The price" $175 for one, "is higher than you may wish to pay but again this is at least a solution" and since we are the only game in town, now bend over, and no, you don't get a kiss.

Are not *new* complete replacement carb racks available for about $400?

Michael