carburreter

maribar · Post by **maribar** » Sat Jun 23, 2007 12:01 pm

Hi folks!
This is the problem: my G9/53 mounts a carburetter AMAL 626 MK1, bore size 26 mm., main jet 260, pilot jet 30.
After few minutes that the engine starts at minimum of rounds the spark plugs become black smoked and after don't spark any more. what can I do? Maybe I must look for the original carb.76AG/1AU? where is possible to find it?
thanks in advance to everybody for your help.
Massimo

Don Madden · Post by **Don Madden** » Sat Jun 23, 2007 6:15 pm

The symptoms you describe are typical of very rich, (fat), mixture. No surprise, as the jet sizes are more appropriate for a 500cc scrambler than your G9.

I don't know of the later 600 series of Amal being fitted to any AMC but Triumph & other twins did.

The later Triumph T100, a similar sized engine but more powerful, used a 628 with an integral pilot of #25, .106 needle jet & 180 main jet. I believe your manifold is 1in, (26mm), & the T100 28mm but you could start with the jet sizes mentioned here & experament. It is likely you would have to use even smaller jets, but it is best to start on the rich side & work down to avoid overheating the engine with a too lean, (weak) mixture.

If you are not bothered by originality, the Mk I is a better carburetor than the original & much easier to find spares.

To fend off those who don't agree with the last statement. those earlier Amals did regulate the mixture well but most are badly worn now, & even when new were a challange to keep leak-free.

Good luck & keep us posted on your progress.

Cheers, Don.

Biscuit · Post by **Biscuit** » Sat Jun 23, 2007 9:02 pm

The Club (Jampot spares) sell new Amal carburettors, I'm unsure whether they do one for the G9.

Surrey Cycles, www.amalcarburettors.co.uk/, supply models across the range, pre monobloc, monobloc and others.Edited by - Biscuit on 23 Jun 2007 8:03:32 PM