Triumph T90 Amal Carb query

[johnm]

Hi everyone
I hope someone can help with a carburettor issue I have on a recently purchased 1963 Triumph T90. It is fitted with a different spec carb to the original 376 monobloc. It is a 625 concentric, similar to the MK1.5 with the choke lever on top, which I believe is of Spanish origin fitted to Bultaco etc.
I have no contacts as to who fitted this and why. The issue I have is should I leave well alone and maybe just service it? Should I replace it with an original? Is a concentric any better than a monobloc?
I am not too bothered about originality a so I do not have a problem with leaving it in place. It seems to run OK with this setup, but with not owning a 350 twin before I don't know if it would run better with the original.
Any help would be appreciated, I am scratching my head a bit on this.
Cheers John

[Zunspec]

Hello John,

If it is running OK I would leave it be. I doubt going back to the original fitment carb will make any difference.

Cheers Geoff

[johnm]

Thanks for that Geoff, that's the line I was thinking of taking.

regards

John

[Antoni]

That's the line I took with the Triumph 21 I had.

It seized going up a long hill - it turned out because the main jet was too small in the wrong carb fitted. If I hadn't ever gone up a long hill probably would never have known. Fitting a bigger jet afterward it certainly ran better!

My point is, make sure your carb set-up is safe.

[Hooli]

Not knowing the carb numbers, is it the same size as the original?
If it isn't it could run better with the right carb, smaller carbs can limit power, larger carbs can run crapper at low revs.

[Notsospeedy]

There's a very handy AMAL reference catalogue giving all the types, settings and parts for bikes from 1940 on.
They had a huge pile at Stafford being given away free and I'm sure will send you out one.

You could then compare the spec of what you have with what it originally had. If they're similar and it works - stay with it. If you want originality, they'll sell you a brand new one.

Malcolm

[DAVE M2]

http://porklips.org/~mason/moto/amal_specs.html" onclick="window.open(this.href);return false;

can be handy