Rejuvenating shrunken carb rubbers

[Mr Bump]

Evening,

Ive done a search on here and other sites, and not really come up with a definitive answer:

Is there a reliable way of bringing Z carb 'rubbers' (I expect they're actually some sort of plastic) back to life and swelling them up a bit? And will they stay like it or harden up again?

I ask because Ive got a set of 'rubbers' that fit between a 750 unitrack air box and carbs. They don't clamp into the airbox like earlier bikes, but sort of push in and rely on the springyness of the material to form a seal.

Mine have gone hard and shrunk a bit, so they no longer seal on the airbox and let unfiltered air in, you can hear it hissing. I should just buy new ones (if available) but I might want to replace the bs34's with something a bit bigger using pod filters (the bike is an 1100) once Ive run it in, so I don't want to shell out for new parts that I might only use for 500 miles or so.

Any advice?

Thanks, Olly

[warren3200gt]

In a word no. Any soak or heat treatment will be short lived at best.

[Gus]

I've heard soaking them in clutch/brake fluid will soften them up

Not tried it myself.

Gus

[Stugill]

In my opinion buy new ones, the money you might be irritated at losing? will be more than offset by the: lack of stress, annoyance and bruised knuckles fitting the old items.

Stu

[Philippe]

Hi Olly

Stu is right! Buy new ones.
GrtZ
Philippe

[MrDavo]

When I restored my CL450 barn find, I found out that genuine NOS inlet rubbers cost an arm and a leg via CMS, and the ones I had were hard as rock after decades of unuse.

A friend from another forum tried soaking them in a special brew (no, not Carlsberg) for a few days which did make them softer, but once I got the bike running it was plagued by runaway tickover and carburation trouble in general.

In the end I had to bite the bullet and sell my soul for a new set, the originals are in a box in the garage somewhere.

[Mr Bump]

Ideal. Thanks for your help.

I suspected that might be the case. I'll have to look up prices.

Or be tight as a duck's arse and temporarily silicone them in until I know if I'm going anywhere with different carbs!

Olly

[moizeau]

I got mine for the ST from here
https://www.ebay.com/str/getor-shop?_bk ... ser&_pgn=2

[Mr Bump]

I got mine for the ST from here
https://www.ebay.com/str/getor-shop?_bk ... ser&_pgn=2

Ideal. Thanks.

Olly