wrong carb too

[coater87]

 Guys,

 Well the basket has the wrong carb also. I have looked and tried to find out what it belongs to as I am sure I will either end up swapping it, or selling it to buy the right one.

 I have found a few number listings for Amal, but none that went high enough on the back-end numbers. If this is something a little odd, I would like it to go to someone who needs it for a spot on resto- I just need a 376.

 Anyway, the carb numbers are 389/40. If anyone needs this, or knows what its for (and please dont say a car, but I would not be shocked at all) could you let me know?

 Thanks,
Lee

[Josh Cox]

Lee,

Firstly I'd like to mention I am no expert, but, do not stress too much about what is stamped on the collar of your carby. It may have been put together from parts etc etc.

You really need to pull it down and see what jets etc etc are fitted.

Go here:
http://www.amalcarb.co.uk/searchByMake.aspx

To find out what was supposed to be fitted, you can also work out if what you have fitted is OK for your bike.

NOTE: MAKE SURE YOU TAKE NOTE OF WHICH SLOT YOUR NEEDLE IS CLIPPED INTO.

It's quite possible that a previous owner upgraded to a new/better carby at some stage.

Good Luck.

[Triton Thrasher]

If it has the same bore size as the opening in the manifold, I'd say it's the "right carb." Itmay not have the right jets and slide (yet).

[fido]

Yes, Amal carbs wear out quite quickly so most A7/A10s will likely have got through two or three over the years, perhaps coming from low mileage crashed bikes etc. As long as the first part of the number is correct the owner would get the tuning right by transferring jets etc from the original carb and perhaps buying a new slide if that was the wrong one.

[coater87]

 Thanks guys,

 Its not the numbers I am concerned with, its the bore of the carb. I believe I need a 1 and 1/16 bore, and this carb seams to have a 1 and 5/32 bore. I felt around at the mounting flange and it seams that to fit this carb the right way I would have to blend the head into the bore and then  maybe suffer loading one side and leaning the other cylinder? Am I way off base here? Will a 389 with this bore work well with a stock G/F?

 Lee

[groily]

If it's for a standard iron GF I reckon I agree with your original comment and you need to get a 376. Better than trying to blend the manifold to the carb etc. And anyway the  velocity of the mixture would be slower through the bigger 'ole, and the motor probably less torquey as a result. Must be people who'd be happy to swap a 389 for one; if I could offer you a 376 with a decent top thread and less wear on the bores I would  - but my 'spare' 376s have already been discarded or recycled at least once and aren't pretty. Only keep them because I never throw anything away in case it could come in useful one day.

[trevinoz]

Lee, the Flash used a 389 carby from 1960.
I can't find 389/40 in my Amal book.
To confirm the size, look at the top of the jet block and you will find a number cast in. This is the size.
I have found measuring the flange side of the carby inaccurate due to distortion. You get a better reading on the intake side.
  Trev.

[coater87]

Hi Trev,

 The only A10s I could find with 5/32 carb bores were pretty high perfomance, super rockets, spitfires, goldstars and such. I think these all had an alloy head on them?

 Nope, I think I am best off at least looking for something closer to the stock G.F. bore of 1 and 1/16- I called around today and the best one of my buddies could do was a 389/16 but I have no idea the bore on that one either.

 Guess its off to E-bay for a 376.

 Lee

[trevinoz]

Lee, the Flash from 1960 on used a 389/45 or 389/48, depending whether it was home or export.
The 389/16 is 1 1/8" so would be OK when jetted to suit. It originally was fitted to a 700 cc Royal Enfield twin, or more likely in your case, an Indian Trailblazer.
Trev.

[Triton Thrasher]

What is easier to find used or new is a 28mm Amal Concentric Mk1, model 928.  Not original or so pretty on your bike though.