Changing the Draphram on Mikuni BS34ss (gs450 1982)

[Guest]

Hi all

I am having trouble changing my rubber diaphragm on my GS450 1982. All the material I can find points to 2 plastic clips holding the diaphragm in place (like here http://jbmindustries.com/Yamaha650.html. In my case, the plastic is metal, is the procedure the same? how do I change these?

This is what mine look like:


This is the only type of referance i could find:


All help is appreciated.
/Mathias

[LAB3]

I'm glad you said something. Although mine are still in tact I was going to change them out just to "make sure" From watching a couple of youtube videos it seems there's a few variations on the BS34SS carbs out there. Sorry, I know this doesn't help you, I'll be keeping my on this thread though.

[chuck hahn]

Pull the old one off...dont clip the rings. Then lube the new one and start it in the groove. Stretch and GENTLY twist and wiggle the new one into place. Once its all in, go around and stretch it a little more to be sure its seated as evenly as it can be. I just did some on my Yammy XS750 which has BS34 carbs. I used a little PB Blaster for lube. Can use a real thin bladed flat screwdriver to work them in to the groove also.

[Nessism]

I'd be careful about PB Blaster on rubber. Might cause swelling.

[LAB3]

I'd be careful about PB Blaster on rubber. Might cause swelling.

I'd be leery of anything with a solvent in it, I'll be using dish soap or glycerin when I do mine.

[Nessism]

WD-40 has solvent in it but it won't hurt rubber. That's what I would use.

[pete]

I've attempted this on my stock 450 carbs, and there was no choice but to cut those rings off the slides.

Are you doing this with the JBM diaphragms? If so, don't bother, none of their diaphragms actually fit those red-headed step child 80 to 82 GS450 slides.

If not, I'd be interested to know what diaphragms you're using.

My solution was to put some GS500 carbs on. Not only did that solve my torn diaphragm issue but they're way lighter as well, although you'll need to swap the rubber intake boots as well and then run a different air filter setup as the intake side of the carbs is very large in comparison with the 450 carbs (60mm diameter).

[chuck hahn]

PB did not hurt the TX750 diaphrams when i did them. IF anyone doubts what is suggested it can always be tested on the junk ones first.

[LAB3]

PB did not hurt the TX750 diaphrams when i did them. IF anyone doubts what is suggested it can always be tested on the junk ones first.

I'm not doubting your experience although there are other ways to do it.

[chuck hahn]

Just a general response. And yes many ways to tackle the same things.