A10 SR Carb - No Air Fler

[mitch]

Hi Guys.
I need some tips please.
Running in my 1962 A10 Super Rocket.
Has standard Amal 389/46 carb with 420 main jet.
No air filter just a good old expansion tube with grill (bug catcher) on the front of it.
I would expect that i need to put in a larger than standard main jet to cater for the better breating.
The bike is runnign hot and the plugs are very light so it does look lean.
I also think i head some pinging when i open the throttle or accellerate hard.
Any ideas or experiecne with this out there, of jetting, tips most welcome.
Regards
Mitch

[Triton Thrasher]

Does your manual contain the Amal tuning procedure?

Briefy- increase main jet by two sizes at a time until it's obviously too rich at full throttle, then reduce by one size at a time until it runs properly.

Fit new metering needle and needle jet and start with needle in richest position and weaken it until it runs properly at mid throttle and doesn't soot up the plugs.

Idle mixture screw and slide cutaway are fine tuning items for low speed and won't destroy your engine.  Running weak on needle or main jet and allowing detonation can wreck your top end in short order- be warned!