I just got this carb, and I'm trying to ID it and find jetting info. It's 1 3/16" all the way through, no taper, and has a short bellmouth (like the Vincents) All I can come up with is a few books that reference it for use on early Vincent Black Lightnings and BSA Goldstars. Would it be an appropriate carb for a mildly built Triumph 650 with a single carb head? Any idea what kind of jet to start with? It's got a 370 main jet and a #6 slide. I know it's going to be trial and error, but I was hoping someone had some experience running one of these on a Triumph and could enlighten me on TT and GP carbs.
First off, this is a TT carb, not a GP. As such, it has an idle circuit and is more tractable than the GP. The 1960 BSA Super Rocket and Spitfire were both fitted with a 1-5/32" TT9, using a 410 main jet, a 7 slide, and the jet needle in the 4 position. A .109 needle jet was used. The slide and jet you have are enough to get started with. David
#245922 - 03/31/097:43 pmRe: Amal 10TT9 (1 3/16") carb- Vincent Black Lightning? Goldstar?
Joined: Apr 2006 Posts: 1,395johnm
BritBike Forum member
That's some really great info- thanks. I saved the all those pages. I just happened to pick up a "Tuning for Speed" by PE Irving from the 60's and it has all kinds of info on the TT and GP carbs too. It seems like a pretty good carb, but the choke is missing. Should I try to hunt one down?
Both the GP and TT carbs have an idle circuit with a low speed mixture screw. They do NOT have a throttle stop as they are considered racing carbs. The rules in that day required that the engine to stop running when the throttle was closed. Making either of these carbs idle is simple, by either drilling a small hole in the slide or filing a notch.
OK, a number 7 side is VERY lean, which suggests this carb was used with a megaphone, a richer slide would be needed for use with a silencer.
Most starting problems were either operator error or ignition related.