Amal TT carb

[Shaun Matthews]

Has anyone got a good technical article on an AMAL TT (1932) it cant achieve full float height because the petrol pee’s out of a small drilling under the pilot adjster before the float valve seats – Any ideas?

[Shaun Matthews]

The petrol comes out of a small hole under the pilot screw – looking at it petrol must flood out of here because it is immersed – I suspect that it is a drill way that should have been plugged ( there for manufacturing reasons to drill the pilot hole through to the choke) – if anyone has a bike with a TT carb on could you please look directly under the pilot screw and see if the 1/16″ hole is open or plugged.

As always feedback appreciated.

Shaun

PS – As Roger knows – The RH Crank went on my Rep last weekend when I was giving it some thrang on the way back from the Borders bike show. – The very nice man is going to make me a new pair so I’m concentrating on a non Scott project whilst he weaves his mettallic magic. Leson to any one else who uses their Scott – Listen to Roger – the cranks do go – Be warned.

[BRIAN MARSHALL]

Hi Shaun, I don’t think you really have a TT carb…… It sounds more like the usual Type 6, typically stamped 206/151R on the mounting flange, in which case the answer is that they all dribble petrol until the engine is running. This is because of the steep 38 degree mounting puts the petrol level above the primary airway. So many Scott carbs have been wrecked by new owners thinking their carbs were leaking and then taking a large ring spanner to the bottom banjo bolt to try and stop the “leak”. Cheers. Brian.

[Shaun Matthews]

Brian

What I didn’t mention is its not on a Scott – but on a 33 Norton International – It is an AMAL TT (10TT27) – sorry if I’ve diluted the purety of the site but like many others the Scott shares it’s garage with several other bikes none of which are quite as much fun but most of which are considerably less fickle.

Whilst waiting for new cranks I’m contenting myself with Bracebridge Street’s awkward cuss! (Now why didn’t I buy that nice Honda?)

[John Farrar]

I use TTs on both of my Scotts.
The correct float height is found when petrol starts to weep(difficult to see- be patient) out of the “hole” underneath the pilot screw when the tickler is pushed down for an instant, ie a jab , not a push and hold down. The petrol should then continue to weep out of the hole, slowly forming a drip.This will only stop on switching the petrol off. If you have raised the float too high you must drain some petrol off before starting again. Under static level conditions there should be no petrol coming out of this hole.
I use a torch to help my aged eyes( you may be more fortunate) , then you can see the film of petrol leaving the hole before a drip forms.
All tests should be done with the bike level .
Take your time, and you should be rewarded with easy starting and good low and high speed performance. I think TTs are magic!

John

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