Amal Mk2

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Oct 25, 2007
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Hi Chaps - I have a 920 Mk2A fitted with a single 36mm Amal Mk2. The bike runs a treat but last weekend whilst out for a ride I noticed that it was not running normally and the idle was unusually high. When I looked at the carb I found that the rubber connector-tube to the manifold was 'sagging' and coming adrift from the manifold and carb body. I did a temporary repair and got home. The engine was bloody hot as it was running so weak. When I then touched the carb the entire rubber tube split and the carb fell off !!. I've bought a replacement tube and will fit it in the next few days. My question is that the last one only lasted about 800 miles - any ideas as to how to make the new one last longer ? One problem is obviously that the entire weight of the carb is supported solely by this rubber/synthetic tube and together with the heat and vibration it gets a hard time.


Hi Mark
had the same thing happen. I use a hoover belt to help suspend the back of the carb doesnt look attractive but function over form etc.
You should also buy the carb rubber from Allens. More expensive but lasts a lot longer than some of the stuff on the market.
Hope to see the bike sometime.
all the best Chris
I use 36mm Mk2s on my 750 and I use BMW inlet rubbers, I've never had one break.
I think they're off an R90S but you'd need to take yours along to check.
2 x Amal 36mm Carbs

Hi Pommie John - I'm interested in the setup on your 750 - I would have thought two 36mm carbs are a bit large. I have a 'spare' 36mm Mk2 and am thinking of perhaps fitting it to make a dual setup. What are your findings with your setup ? What inlet manifolds are you using. One thing that impresses me is that idling with a single carb is very good - is idling on your twin setup OK - I remember idling with the original twin Mk1 concentrics was difficult to setup and was never very 'steady'.

Well, my 750 is a race bike with a fairly modified engine. The 36mm carbs worked well for the track, but I don't have it set up to idle. It also won't take full throttle under 4000rpm, so it's probably not a great set up for a road bike.
We had to modify some standard inlet stubs to make them fit the 36mm carbs by cutting the flange off the carb end of the stub and building it up with weld and turning it to fit the carb rubber.
Also , they are both right hand carbs which makes it difficult to adjust them.

I have recently changed to a pair of 34mm dell ortos. i haven't got them jetted in properly yet so I can't tell you whether they are better.
Amal Mk2
Hi John - thanks for the reply - based on what you say and the fact that my bike is a road bike I think I'll leave it alone.
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