hear and see my bike

Carbs are clean, floats are working, no longer leaking, pilot screw o-ring is disentigrated (not sure how big of a deal that is for the moment) does this rich or lean, or just dies.
http://www.youtube.com/watch?v=PJ-mSPLKayQ

I'm surprised it will even start. I think you really need to go over the carbs big time. http://www.jba.bc.ca/Bushmans%20Carb%20 ... html#FLOAT

Lot of other information on the Amal site too.

Are you getting enough fuel delivery from the petcocks. The pilot gasket will let lots of air in too, get a gasket set, can't hurt. That thing should rev up instantly with the throttle. Nice looking bike.

Dave
69S

Oh Blimey,

You've got a substantial air leak there, to put it mildly!

As Dave says, it's amazing it'll even start like that. Check the O Rings between the head and carbs are good. Renew the air screw and throttle stop o rings on both carbs to be sure. Have you renewed the exhaust gaskets? Don't know what it was like when you last fired it up, but it's always wise to use a process of elimination and fiddle with one thing at a time, so you have a point of reference.

If that all fails, check the carb flanges are flat. These are very easily over tightened on Amals and the resulting bowed flanges can produce the mother of all air leaks- which is what you have! You can check for this by dribbling oil over the flanges while it's running. Look for air bubbles and a marked difference in the tick over speed.

Pull 'em off and flatten the bowed flanges down on a flat surface ( like a pane of glass) and some valve grinding paste.

Concentrate on the Postive aspects old chap- abit of tweaking and you've got an amazing Norton!

In my experience meager as it is that sure sounds like sticking too advanced points mechanical advance or just plain set too advanced baseline. If electronic I'd suspect low voltage and/or bad charging or power conveying connections.

Best idle should be very close to 1.5 pilot air screw tunes out, if less then float too high, if more then float level too low. Of course check air leaks but still sounds more like electrical miss fire that fuel to me, but then again I can''t always tell either.

Also have had water in bowls do similar. Starts up eventually then runs rough with some short intervals of teasingly smooth running then suddenly stall.

Carb rebuild kits. Set you back just over $50 with shipping from the UK.

Yes 2 above and don't forget the torque ratings of manifolds 2 carbs , super low , warpage over.

After having carb bolts back out more than once I gave up on the o-rings and use-made a rubber gasket to be able to nip up normal tight and not sweat bending the pot metal-mis cast flanges more. Locitite on these makes a tedious job rather more miserable effort. I use regular thick heat insulator gasket against the head surface.

Hello Andrew,

Just looked at your vid again. BEFORE you start it for the 2nd time, it looks like you've tickled the carbs again? And then when it starts, it won't 'answer' the throttle. Then I think you've fiddled with the choke lever. I'm assuming this means you've put the choke on, that is closed the air lever?

Both actions richen the fuel/air mixture. I think this indeed points to a huge air leak, and the most likely source is where the carbs bolt on to the inlet manifolds. In other words, I really reckon the carb flanges are bowed. Over tightening the carb mounting bolts causes the flanges to 'bow', like stretching back the string of a Longbow. If you get a big air leak here, no amount if fiddling with the carb settings will prevail, cos you're getting way too much air in the mixture. When you open the throttle, you are basically introducning more air and the carbs have to match that with more fuel.

So you can either renew the carbs and be VERY careful how you tighten their mounting bolts, or grind the flanges down on the existing ones, as suggested in my last.

I've had this problem on BSA Bantams - 2 strokes are far more senistive to air leaks. Persevere old chap, and then you can whistle a more cheery tune (and get flies in your teeth :mrgreen: ). Looks a great bike otherwise, so don't tear your hair out too much- you'll get there.

Do let us know how you get on. And if it's all Greek to you, we've all been there too so just ask and folk will chime in.