Reviving Carb rubbers?

[The_Yellow_Ardvark]

No sniggering at this.

Look on line or local adult shop for rubber/latex restorer.

It does work.

 

[slim_boy_fat]

No sniggering at this.

As if.......

 

[ukracer]

Good luck with that. Over the years I have tried many times with many different recipes. It never works for me. My understanding is that once the rubber has degraded, it's game over and it won't grow back (aka "soak in"). The only thing that helps is heat but that only lasts until you get them on, then you rely on them going hard again whilst clamped in place...

Would love to know how you get on.

Yeah this topic interests me. My problem is i cant get the rubbers off easy to bag them up as they are wiper rubbers on my saab car windows.......they just dont clear the outside rain when you raise and lower them........i have been told to use WD 40 . My recolection of that and rubber is that it does indeed go softer but it swells a lot if i remember correctly.

 

[Cobbler]

You have to be careful with WD40, it attacks some plastics & rubbers, I know of someone that got it on his watch & it clouded the face. Also I used it on my air rattle gun, very soon after it the trigger wouldn't hold air, when I stripped it I found the rubber seal had dissolved into a sticky goo. I can only assume it was the WD that did it, I stick to a bit of 3 in 1 now.

 

[Farside]

The wintergreen thing is well known on the GS Resources forum, and by this time there has been some long-term feedback on its effectiveness.
Most got it to work ok, and were able to get their carb boots to hold perfectly fine, but it seems that after a couple of years the boots just go hard again. The lost plasticiser in the rubber is only temporarily made up for by the presence of the wintergreen - enough to do the installation job, but it doesn't stay there.
This means that old hard rubbers can be re-used, but not relied on to continue to seal, or have any predictability about how much more service life they've got in them.

 

[Screwdriver]

Yes there's a whiff of the Emperors new clothes about this. Everyone seems to know someone who says they have a magic formula, no one has ever demonstrated it working. Natural rubber is soft like honey, it gets mixed with other substances depending on what it is you're producing and there are an infinite number of varieties. One common factor with rubber is vulcanising.

Rubber is stretchy (like a rubber band) because it is made up from long chain polymers. To stop it being so gooey, it's mixed with sulphur and heated at high pressure. This locks isome of the polymers together which are like dinky little springs. The more locked together they become, the harder the compound.

The process is not reversible nor does it ever stop. Over time the rubber will continue to harden as the stretchy spring like polymers become broken up and stuck together. Just like the vulcanising process but over a much longer timescale. The fundamental mechanical properties of the compound have changed irreversibly. Bit like having a mattress made up of loads of long springs and you just keep tack welding them together.

Heat will help soften it in the same way heat would soften your welded up mattress but when it cools it goes hard. The common accepted wisdom is that "natural oils" leak out of the rubber over time. While that may be true for some compounds, oil does not make rubber springy and there's little chance of oil penetrating a solid rubber!

Some solvents might appear to soften rubber and I'm sure they will but you don't want soft, you want "rubbery" (springy). I suspect all they do is dissolve the outer layers of hardened rubber which would be the hard skin that aged rubber forms.

Rejuvenating old hard rubber? <Victor Meldrew mode> I don't believe it....

 

[Jlg]

If you haven't tried put them in some boling water or heat it up wit a blowtorch then put it back together as fast as you can

 

[pod70]

Rather than a blowtorch, I usually use a hot air paint stripper to warm the rubbers. I've found with a lot of bikes if you don't use the original clamps, thicker jubilee clamps will just pull the rubbers back off their stubs. I'm with screwdriver regarding the rejuvenating properties of Wintergreen. Have you tried David Silver Spares for new rubbers (might be a bit pricey though)

 

[octo0072000]

Jig beat me to it just boil them in a pan refit while still warm

 

[addjunkie]

You could be ing David Silver or who ever and buy some new bits

 

[Shox Dr]

Members on the XRV.org forum report they are obsolete. DS dont have stock.

Forgot the wire lockers so it will have to wait until tomorrow...again

 

[chunkolini]

There is a bike breaker in germany who specialise in Africa Twins, but I have lost the link

 

[Shox Dr]

Boiling them as I type this.

 

[Shox Dr]

Well squigey

 

[Shox Dr]

Not for long though, made and had tea while they were boiling/cooling down, waited too long. Either one goes on or the other. Rubbers have to be fitted to airbox before fitting rubbers to carbs. nightmare.



This is the rear as it’s the hardest to get on even with it out of the airbox.

I’ve given up on the front for tonight.

 

[Screwdriver]

You have to put them on while they're hot!

 

[JEZGUZ]

Having the same problems with my Nordwest, inlet rubbers are like hens teeth and haven't been available for years, I managed to get hold of a pair but getting them to fit is a nightmare, I keep having a go at them every now and then but still no joy. I'm considering a different carb set up just to get around the problem.

 

[Screwdriver]

Looking at that, is it possible to fit them to the carb inlet with the flange off the carb, then bolt the entire flange/boot on in one go? Then worry about fitting it to the airbox.

Getting a lipped fitting over the airbox is a bit like fitting a windscreen rubber - use a bit of string to pull it over...

 

[mike 109444]

Have you looked into getting them made up in silicone, much like they do with car heater hoses ? (don't know if it would be to pricey though)

 

[Farside]

There's NRP in the UK http://www.nrp-carbs.co.uk/shop/index.php?route=product/category&path=41 who might have suitable boots, and JBM in the US http://jbmindustries.com/ who have a steadily growing range of boots. Many boots swap over from make to make/model, but unless you know for sure, it's a bit of a gamble.