Diaphragm Repair

Can someone confirm the method of repairing pin holes in the diaphraghms,
cut small piece of condom & stick with tire repair adhesive?
do you cover the hole from both sides?

 

I have repaired a couple of small pinholes successfully using Plastidip, applying with a very small paintbrush.

 

What's Plastidip? is that Kiwi specific?

 

if the diaphragm has a hole it's best to use a condom, of course this has nothing to do with motorcycle repair, more like family planning

 

/\hehehehehehe/\

 

Pilock, you've spelt your name wrong.

 

Dammit, Wiz I nearly woke the kids up laughing... seriously, Plastidip isn't Kiwi exclusive, it's good ol' Yankee ingenuity at its finest: http://www.plastidip.com/home_solutions/Plasti_Dip based in Minnesota. They also make liquid electrical tape http://www.plastidip.com/home_solutions ... Insulation which I have heard tell is good for repairing cracked rubber intake manifolds.

 

I've used liquid electrical tape, although it hasn't had a long durability test yet.

Nice thing about liquid electrical tape is it comes with a brush applicator. I painted both sides of the diaphragm.

 

Plastidip should be available from most engineering supplies, it is oil/fuel resistant so is ideal for diaphragms. I purchased the a spray can, red as it was the only colour available at the time and sprayed it on to some sheetmetal then applied with a very small artists brush.

Wipe the diaphragm over with a rag and spme isopropyl alcohol before hand to clean up and use a cotton bud with IPA to clean out the pin hole (quick dab).

 

I have now used R.T.V. (room temperature vulcanizing) on the pin holes,
Liquide Vulcanisant, AU $ 2.50 / tube.
I have tested it with some fuel & had no adverse reaction.
I cleaned a small area around the holes with 1200 paper & made sure the material passed through the pin hole, so in effect creating a "rivet" of vulcanisant.
Only time will tell if this is a permanent fix.

 

I'll add my voice to this query...

I've used the Plastidip Spray can version on my carb diaphragms and it's worked a treat for around 20,000kilometres. I haven't opened them up again yet but will do so over the Christmas break but I don't detect any problems with the vacuum/fuel delivery system and the carbs respond really well to throttle changes.

Only trick is that you hold the can a fair distance when spraying so that you give it a light coat...and then maybe a second very light coat. And keep the cat away from where you're spraying (again, from personal experience)!! And then let them dry for a day or so before re-installing.

When dry, the diaphragm might be a tiny bit firmer than before but no adverse effects have been so far detected.

If need be, you can spray a small amount into the lid and use a small brush to dab some of the pinholes beforehand.

It works, and it's cheaper than a new diaphragm/carb slide assembly.

 

Liquid Electrical Tape works best for me.

Get rid of the "Dabber" that's attached to the top of the can.
It's way too big for fine work and just makes a mess every time you pull-of the cap to pour-out some product.

Artists fine-line paint brushes.
Liquid Electrical Tape
Glue stick
Small-sized Funnel
Masking Tape or double-sided tape.

Cut the neck of the funnel away so that the Diaphragm will fit and let you spread the rubber out on the curved surface.
Apply Glue Stick coating toi funnel
Place Diaphragm in place.
Spread-out Rubber and smooth-out.

Open Can of Liquid Electrical Tape.
Pour-out 2 small drops onto 3X5 Card
Use artist brush to collect product and spread over pinhole.
Do initial coat.
Let dry.
Do second and third coat after succeeding coat dries.

Product cures rapidly.
Spread-on quickly.
Don't touch applied product when it begins to cure.

Use tape, glue stick or assistants fingers to hold Diaphragm Rubbber out smooth --> SMOOTH ... while the product is being applied.

 

Wiz, as long as the RTV stays "stuck" you should be OK, it's certainly not going to be "stiffer" than the surrounding rubber. My only concern would be if the RTV pulls away from the rubber over time, roughing up the area may have been the ticket. Are these the Kawi carbs you're dealing with?

 

You could try NRP if the exchange rate works in your favour

http://www.nrp-carbs.co.uk/yamaha_carbu ... hragms.htm

 

WHOA. Piston/diaphragm assemblies go for over $100 US. I just looked up the exchange rate, their 29GBP price for the Yam 550 diaphragm at 1.53 is $44.37. Even with international shipping, that's gotta be a bargain... at least for us here in the States. Thanks.