restoring hardened rubber

[pompousporcup...]

Hopefully some may find the following helpfull.
As some of you may well have found out when working on older bikes, the rubber boots that are found between the airbox and carbs go hard making it almost impossible to put carbs back in place.. my experience with this has been with old kwakers and it lead me to shelve the airbox in place for pod filters which are a right pita the get running.

new airbox rubbers for my old bike come in around £60 for 4 which, whilst not overly expensive, is an expense i don't want to take when the rest of bike is costing an arm and leg...

So, ive let them soak in a 1:3 (100ml:300ml) solution of Wintergreen essential oil and IPA... 100% wintergreen and i think 99% IPA which is the best i could find.
£12 all in isnt too bad and the rubbers have gone from a solid plastic to pretty much the original factory feel.. soft as you like

[pepperami]

When you say IPA, you're not talking about beer are you?
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I am the sum total of my own existence, what went before makes me who I am now!

[stinkwheel]

Just watch the wintergreen in skin contact. It can be nasty. Wear good gloves or avoid skin contact altogether.
____________________
“Rule one: Always stick around for one more drink. That's when things happen. That's when you find out everything you want to know.”
I did the 2010 Round Britain Rally on my 350 Bullet. 89 landmarks, 3 months, 9,500 miles.

[Rogerborg]

That's... unexpected. Please keep us posted on whether this is a long term solution, or whether they disintegrate in short order.
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Biking is 1/20th as dangerous as horse riding.
GONE: HN125-8, LF-250B, GPz 305, GPZ 500S, Burgman 400 // RIDING: F650GS (800 twin), Royal Enfield Bullet Electra 500 AVL, Ninja 250R because racebike

[Tracer1234]

Interesting post is interesting.

Where does one buy said ingredients?
____________________
Riding: Yamaha MT-09 Tracer Occasionally Riding: 08 Suzuki SV650, Potato: 2011 Yamaha YBR Custom.
Used to ride: 2015 Yamaha MT-09 Tracer (smidsy) 09 Triumph Street Triple (P/X'd) 08 Yamaha YBR (Sold)
CBT 04/14. A: Mod 1 & 2 13/04/15

[pompousporcup...]

ebay can prolly get it from some health type shops but i have yet to look

[pompousporcup...]

[ThatDippyTwat]

[ADSrox0r]

I've restored carb rubbers for the Aprilia by putting them in a bag of brake fluid for a week. Works a peach, they were proper 'tap tap' rock hard and came out lovely and pliable and have stayed that way with no degradation over a year later.

I've done various rubber mountings and bushes on cars this way over the years, you just have to make sure you use DOT3/4 fluid and not DOT 5. That makes your rubber go...not very rubbery
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Current bikes: '08 VFR 800 VTEC(yo) , '07 ZZR1400 Winter hack: '95 Aprilia 650 Pegaso Currently lusting after: RC30

[stinkwheel]

Other stuff I've come across is aerospace 303 which is a UV protectant for plastics. If you do the black plastics on your bike with it periodically, they stay black and tend not to go brittle and faded.

Prevention rather than cure.
____________________
“Rule one: Always stick around for one more drink. That's when things happen. That's when you find out everything you want to know.”
I did the 2010 Round Britain Rally on my 350 Bullet. 89 landmarks, 3 months, 9,500 miles.

[Serendipity]

Very interesting. I'm just pulling my 23 year old CBR600F carbs off so this may be something I try on the inlet rubbers once I evaluate how stiff they are.
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2007 CBF1000-ABS - Commuter heaven | 1994 CBR600FR - Awaiting defibrillation

[pepperami]

This thread is getting my vote for the best thread this year
I have piles of assorted rubber "stuff" in my bike related junk pile.
If I can make some of them usable again, winner winner chicken dinner!
I know I can get most rubber parts for my Honda Superdream from Dave Silver, but a few pennies saved = happy Pepperami

A short term method for hard rubbers that I have used with much swearing and scolded fingers is to put the hard rubber/s into hot water for a while before trying to put them/it on.
Much faffing about, but it got me out of a pickle a couple times.
____________________
I am the sum total of my own existence, what went before makes me who I am now!

[pompousporcup...]

[pompousporcup...]

[stinkwheel]

I'd use brake fluid with extreme caution.

It does soften plastic but not necessarily in a good way. It can make it go plastic and floppy rather than elastic.

There was a guy on another bike forum who did an experiment with chain o-rings and various solvents to see what effect they had for use as a chain cleaner. The ones in brake fluid swelled up to nearly double their normal diameter (both in cross sectional area AND o-ring diameter) and went limp as cooked spaghetti.
____________________
“Rule one: Always stick around for one more drink. That's when things happen. That's when you find out everything you want to know.”
I did the 2010 Round Britain Rally on my 350 Bullet. 89 landmarks, 3 months, 9,500 miles.

[pompousporcup...]

10 day update. I successfully fitted the airbox to my bike using the restored rubbers. I left each in solution for only 24 hours and they're all still soft.
They bounce back to the original shape too

[Bru]

Hi. I think that 'Practical Sportbikes' did an article about this, maybe within the last year. Their solution (sic) was to boil the rubbers in a mixture of wintergreen oil and water. Not recommended indoors, allegedly.

[A100man]