Diaphragm repair

I was looking around on the internet, and found a thread on another forum about repairing a carb slide diaphragm. They used gorilla glue. Said it worked very well. Anywho, I have 2 giaphragms that have tears in them so I glued them this morning when I got to work. Seems good so far, put too much on them, had to go back 3 or 4 times to clean them up since this stuff expands 4 times its size during drying. It stayed flexible, and is stuck good. Gonna give it the on carb try this evening. I figure, even if it only lasts a couple months, it was worth a shot. When Uncle Sam sends my refund in Feb., I'll get some new ones then. Will let you know the outcome.

 

Sounds reasonable for a short term fix, as long as the gorilla glue can hold up to fuel vapors and whatnot. I know silicone sealers will turn into snot upon contact with fuel... don't ask how i figured that out.

 

The guy that wrote the original thread had used different types of adhesives on nitrile gloves. The gorilla glue withstood straight gas, and carb cleaner. He said at the point where the nitrile started dissolving, the glue stayed intact.

 

Put the carbs back together and back on the bike this evening. Fired it off. All for carbs are opening up now, throttle response is good, revvs like it should. Didn't get to completely re assemble the bike and take it for a ride due to darkness, but hope to go for a ride tomorrow eve. Will post how it runs.

 

Wow, I knew gorilla glue was good, but that kind of chemical resistance is impressive.

 

Went for a short ride this eve. Sucked. Starts falling on it's face at about 5,000. Pulled the tank, started pulling plug wires while it was running. If you pull the wire off of either the front cylinders, it dies instantly. If you pull either off the rear cylinders, it stumbles down and dies. Oddly enough the repaired diaphragms are on the front cylinders. Guess I'll pull her back down and go through the rears. Oh, by the way, it runs rich at idle.

 

What year bike is this?

 

It'l still idle even with bad diaphragms, they pull the needles up when you give the bike gas.

 

bike is a 1983. I checked with the airbox off, it is pulling the needles when you rev it. all seem to be equal. Probably missed something in the 2 rear carbs. The air screw doesnt affect them at all. Weird, the front two seem fine. Air screw changes like normal. Run them in till it starts bogging, then back out a round. No affect at all when you adjust the rear.

 

I'd say your quick fix has probably let you down. The symptoms are typical of slides not working properly - thought it certainly could be other things as well. Considering that you just did a patch job on the diaphragms I'd look there first before moving on to other possible causes.

 

The patched diaphragms are on the carbs that seem to be working fine. Gonna tear it back down. At least these bikes are easy to work on

 

If your air screws have no effect its likely there is an air leak on the carbs, whether at the baseplate or the boots that connect to the motor( if it has them) With the bike running, spray brake cleaner/carb cleaner around the carbs but not in the intake of them. If you get a fluctuation, they are sucking in air from other places as well.

 

Are these available anywhere?


Thanks

Kelvin

 

Year and model of bike would help significantly.

 

Opps sorry 84 VF1000f,

Thanks

 

update. Haven't been on in a bit. I pulled the carbs back down, again. The springs were in the correct order, but the needles were not. While I was in there I re-repaired the diaphragms. Meaning I removed the stuff I previously used and sprayed them with plasti-dip. That stuff is the s*17. There as flexible as the non repaired ones, and look good too. Put it back together, huge difference. Will redline now on revvs. Pulls on highway to redline. Gotta go in one more time to change the mains. Lean above 5000. I'm guessing it was a combination of the needles and the cable tv coax plug wire that was causing the trouble.

 

dcil, I have an 84 VF1000 also, and have tears in two of my diaphragms. I was going to go the plasti-dip route too, but I read that it does not stand up to gasoline. Have you pulled your diaphragms off and looked at them to see their condition?

If still good and running good, can you share your procedure and trials in getting the plasti-dip to work?

Thanks

 

Worked great. You get very little gas at the diaphragm unless you turn it upside down. Mostly all you get is a little vapor. I've talked to people who have ran them with plasti dip that have gotten several years out of it.

 

I also found this website NRP motorcycle carburettor repair specialist. Looks like they have replacement diaphragms for about $55 USD.

 

I bought the diaphragms from NRP, easy to get the diaphragms out and the new ones in, just need to make sure the holes line up properly on the diaphragm to the flat part of the slide. Wow, what a difference! I had trouble installing at first, but then I turned the diaphragm down on itself, emulating the slide being all the way open. Installed easily.