Hitchcocks Forum

Hello, I want to put new Amal carburetor to my 2006 iron cast bullet 500. I know that for installing 32 size I also have to tune cylinder head, which seems right now too much work. So from that point of view size 30 would be my choice. But: would I notice much upgrade from standard 28 carburetor to Amal 30? Or would be better to go for bigger Amal 32? I already have new exhaust (50's style from hitchcocks motorcycles). Thanks

The size of the carb to be fitted depends entirely on the diameter of the inlet port. Ideally they must match size for size. There will be no advantage from fitting a 'bigger' carb if it is not of the same size as the port in the cylinder head. In other words, so far as carburetors go, bigger is not better!

As presto says there is NO advantage to fitting bigger than the existing inlet tract, in fact there is a distinct disadvantage, a bigger carb will slow the airflow speed which will give poor mixture control and resultant bad low speed running.

Why do you want to fit an Amal? There's nothing wrong with the Micarb and you could have quite a fuss getting it to run properly. Also it won't make the bike run any better. As others have said, increasing the carb size does nothing but cause problems without altering the inlet to suit.

As others have already said. So if you want to go faster, buy another motorcycle. Royal Enfields are bought for their gentle riding enjoyment.

Leon, some people enjoy tweaking these simple machines

Yes Chris, you can make them go really fast (just ask the Bullet Whisperer) but just sticking a bigger carb on will do nothing but harm.
Royal Enfield are not renowned for their cutting edge technology but they probably have more idea about which carb to use than we do.

I know Pete, that's not what I responded to.

Anyone can make a mistake, said the hedgehog as he climbed off the hair brush.

Sorry, misunderstood.