failed Amal manifold rubber boot
- Thread starter jseng1
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Maybe here at Allens Performance Ltd (UK)
http://www.allensperformance.com/produc ... folds.html
or Niche Cycle Supply maybe....
http://www.nichecycle.com/ncs/
http://www.allensperformance.com/produc ... folds.html
or Niche Cycle Supply maybe....
http://www.nichecycle.com/ncs/
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Hi Jim, sorry I can't help you ,but Allens seems to be a good source, at least for us in Europe.....
Yes the Amal failed after a while , some cracks ............!
Yes the Amal failed after a while , some cracks ............!
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Hi jim, no I do not yet had bought them, but will try asap.........and will keep you inform!
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Try here:
http://www.mikunioz.com/r_m_flanges.htm
Thanks for that, I usually buy the alcohol ones from Mick Hemmings - never thought to look.
http://www.mikunioz.com/r_m_flanges.htm
Thanks for that, I usually buy the alcohol ones from Mick Hemmings - never thought to look.
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lcrken
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Jim,
what sort of failures have you been having with the 2928/123 adapters? I've been using them for over 30 years now with no problems. I have occasionally replaced them when the outside shows serious cracks, but not because they were leaking, just as insurance. I've been using one set for over 10 years that I stretched enough to fit the MKII 36 mm carbs, and I'm finally replacing it this year because I'm seeing more cracking, but they do not go through to the inside yet, and it doesn't leak. I wouldn't expect rubber products like these to live forever with the heat and ozone they are exposed to, but they do seem to last reasonably long. Are you having a different experience with them?
Ken
what sort of failures have you been having with the 2928/123 adapters? I've been using them for over 30 years now with no problems. I have occasionally replaced them when the outside shows serious cracks, but not because they were leaking, just as insurance. I've been using one set for over 10 years that I stretched enough to fit the MKII 36 mm carbs, and I'm finally replacing it this year because I'm seeing more cracking, but they do not go through to the inside yet, and it doesn't leak. I wouldn't expect rubber products like these to live forever with the heat and ozone they are exposed to, but they do seem to last reasonably long. Are you having a different experience with them?
Ken
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The first set of boots I used came with the alcohol kitted Amal Mk2s and they cracked. The second set have been on for years . I would have thought that the petrol boots would be neoprene, and I cannot imagine why something different would be used for alcohol, unless there was acetone involved in blending the fuel. I never use methanol racing fuel which can have acetone and vegetable oil added, only ever pure methanol. I always remove the jet covers from the fuel bowls of the carbs while the bike is standing in my garage, so the white crap does not form and block up the jets next time I use the bike.
Unfortunately we cannot buy BP JA or JB racing fuels (50s Maserati fuel) these days, it would have been lovely stuff in a standard comp commando engine. They had 60% and 70% methanol, and the rest was benzene and acetone with vegetable oil. My 500cc short stroke Triumph used 12 to 1 650 pistons and was on 10 to I comp. - Went the best ever on BP JA. I think its got something to do with calorific value of the benzene compared with methanol. We could probably use toluene instead of benzene these days.
Unfortunately we cannot buy BP JA or JB racing fuels (50s Maserati fuel) these days, it would have been lovely stuff in a standard comp commando engine. They had 60% and 70% methanol, and the rest was benzene and acetone with vegetable oil. My 500cc short stroke Triumph used 12 to 1 650 pistons and was on 10 to I comp. - Went the best ever on BP JA. I think its got something to do with calorific value of the benzene compared with methanol. We could probably use toluene instead of benzene these days.
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I don't think its just the booze in the fuel as I almost never get any of that but my carb boots have cracked in a few seasons unknown to eat rings and ruin engine sealing with blow by the Krank PCV couldn't keep up with. Similar on fork boots now in tatters after couple years. Wife and I have noticed this last decade rubber bands and jar seals and pencil erasers all tend to harden or crack a lot faster than the decade prior. We assume there must be more ozone around or the rubber is of lessor quality. Peel came to me with Amals and air boots and fork gaiters at least a decade old and were still ok like Ken Canaga reported. The got replaced and didn't last a couple years. Carb boots in Trixie were new in 2011 but broke up in 2012 and ate rings. New gaiters put on same time didn't last much longer but mostly collapse down near seals so ain't bothered yet.
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It would be interesting to know which rubber compounds were used in the two types of boot, methanol or ethanol rarely attack any polymer unless there is an aldehyde or ketone in the mix (intended to help blending ?). Petrol is much more aggressive towards rubber.. I cannot think of another reason for the compounds to be different. I'm fairly certain the ones on my bike are intended for use with petrol.
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Get a load of this:
I did a overnight gas soak test. The alk boots #2928/119 swell up because of the Ethanol in todays fuel.
The gas boots #2928/123 did not swell.
I couldn’t believe it so I repeated the test and got the same thing.
So the Alk boots #2928/119 do NOT tolerate todays gasohol mix and they prematurely crack as well.
The common gas boots #2928/123 work fine – do not swell and according to reports – don’t crack for years.
I did a overnight gas soak test. The alk boots #2928/119 swell up because of the Ethanol in todays fuel.
The gas boots #2928/123 did not swell.
I couldn’t believe it so I repeated the test and got the same thing.
So the Alk boots #2928/119 do NOT tolerate todays gasohol mix and they prematurely crack as well.
The common gas boots #2928/123 work fine – do not swell and according to reports – don’t crack for years.
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