Throttle Valve Sticking

Having an issue with my right carb throttle valve sticking wide open. I took the top end of the carb apart cleaned it an put it back together, the thing is still sticking. I decided to croacus cloth it but to no avail. I know that there could be a couple of things causing this but I can't ride the bike like this so I think I will order a new throttle valve and spring hopefully that will do the trick, anyone else have a similar problem? If so what was the fix?

common Amal malady from over tightening the mounting flange bolts. I've seen an expert slap it in a bench vise, give it a calibrated twist, then the slide fell in and out. 60 seconds.

Let me tell you about the time I was climbing Mt. Washington Auto Road on a 69 BSA Lightning, riding two up, throttle kept sticking.... :shock: :mrgreen:

Thanks concours, It seems that's what happened to mine along the way, instead of messing with it too much I decided to sand down the slide a bit, worked like a charm.

Ugh, the soft pot metal on soft pot metal will not give lasting mixture control and may again get sticky, which could stick on a kick off and end the game. Good idea to spend on the new anodized slides. Btw the Amal distortions are 50+ yr old subject and has been investigated by metal casting experts who found the casting form works ok for 28 mm and smaller carb bores but 30 and above the cooling produces distortion in bore shape and flange flat ness Right Out of The Box and handling outside of box may also, so please put this factoid in your reasoning's on why yours might need beating with a dowel inside or tweaked in a vise - that may have nothing to do with that HUGH group of ham-fisted wrencher's ALWAYS blamed, but actually innocents just nipping up so they stay nipped for a time. I think there's been 2 or 3 reports that Norton parts some times ain't up to snuff right out the box. One upgrade I don't think is cheating w/o a factory part number - is replacing the o-ring with a full rubbery type flat gasket you can clamp down on w/o any bowing to matter and pushes back on the threads to help stay tightly sealed.

Decemberist said:

Thanks concours, It seems that's what happened to mine along the way, instead of messing with it too much I decided to sand down the slide a bit, worked like a charm.

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You might be cutting off yer nose with that solution. It's really a quick fix with an appropriately sized wooden dowel, a bench vise and a heat gun set to low.

acadian said:

Decemberist said:

Thanks concours, It seems that's what happened to mine along the way, instead of messing with it too much I decided to sand down the slide a bit, worked like a charm.

Click to expand...

You might be cutting off yer nose with that solution. It's really a quick fix with an appropriately sized wooden dowel, a bench vise and a heat gun set to low.

Click to expand...

I didn't realize that there was a good "fix" for the mixing chamber. I knew that it had been distorted by a PO but since I don't have the experience I thought better of damaging the $150+ mixing chamber and instead opted for the quick sanding job of the $30 slide. I think Hobot is right I will try the anodized slides but I am too inexperienced and now due to a house restoration poor to afford a new chamber if I mess the one that is currently fitted. BTW, I found out about the crappy pot metal slides from a quick twist of the throttle on a busy street...Scary stuff I now know that my kill switch works just fine. :shock:

Hm, still might be best id to try to measure-test by fit etc, the slide bore and tweak it more perfect - maybe with where ya saw the slide witness marks to guide. Might try spray paint the slides and run a bit to see where rubbing most for bore distoring into it. My old Amals sldies and bores got to fluted beat worn state so got andodized with #3 cut out to help make up for the air leaks and more off idle spunk and pretty much one step on starts, no matter how many watching or me bragging about thumb commensors lowering one's IQ over time.