Norton Commando Ride - Jammed on Full Throttle!!

[@stefansikora5183]

Stuck throttle slides are a really scary thing. Brown underpants recommended. I had similar issues on my Commando after i fitted new Amal premiers. The carb bodies warp easily when the nuts on the carb flanges are overtightend just a little bit. When you take out the slides and remove the needles, the slide should drop to the bottom without any resistance. If it is sticking, the body is warped, which will only get worse when the bike gets hot.

[@pauldavies3764]

Single Mikuni better

[@stefansikora5183]

@@pauldavies3764 Depends on what you think is "better". I had a TM34 flat slide on my Commando once. Absolutely gutless above 3000rpm. The problem is that people always compare worn out Amals with a brand new single carb. Of course it starts better, has stable idle and has (surprise) no problems with synchronising. Thats okay when you are trundling along at low speeds. But when you REALLY give a handfull of throttle on a Commando with well setup (and NEW) Concentrics it is miles ahead of a single Mikuni. Problem is that Concentrics are ready for the trash bin after about 20000km. The Mikuni lasts much longer.

[@pauldavies3764]

@@stefansikora5183 back in '75 i had a '71 roadster and it was quicker than my mk3 now. 750's were faster anyway but there were only 2 positions on throttle,wide open and shut. My 850 is a lot smoother,and it will fly when i want but old bikes need looking after so i ride accordingly.

[@rickconstant6106]

I had the throttle stick open on my mk 2a, 50 years ago. It was early morning, middle of winter, with a dusting of snow on the ground. I set off for work, shut the throttle to slow down for a junction, and it stayed open. First reaction was to pull the clutch in, so the revs went right up, then, not really thinking clearly, I let the clutch back out. At this point the bike started fishtailing, blew right through the junction, fortunately clear of other traffic, before I came to my senses and hit the kill switch. Luckily, I was able to let it coast to a halt without hitting anything, or dropping it on the very slippery road. A real brown trousers moment. After snapping the throttle open and closed a few times, I restarted it and carried on to work. I was lucky to survive the recklessness of youth - nowadays I would have stripped the carbs and cleaned the slides before daring to ride it again, and certainly not in the snow.

[@Chris.rooke150]

Thanks for that. It's that sudden panic that's the problem - you just can't think fast enough, and then it's too late! Lucky in my case - very, very lucky in your case. 👍

[@robertcameron5007steelwheel]

Never heard of the throttle stuck i raced commandos in the early seventy used full throttle a great bike we did constant service no problems.

[@tribsa7503]

Thank goodness you were on an open road with little traffic and no sudden bends. A heart pounding moment I’m sure. Glad the rest of the ride went without a hitch!

[@donplenderleith6044]

Nice video editing btw front and rear cameras. That is a very nicely modernized Norton that maintains the classic look. Lots of theories on the cause of the throttle sticking open. My guess is a slightly rough area in the guide slot on the slide that got hung up on the guide pin in the bore. That’s why it only happened at full on. Fortunately the spring pressure was enough to snap it down! Lovely country roads too. Where abouts are you?

[@Chris.rooke150]

Thanks, Don. I'm in Sheffield, but the ride is mainly through the beautiful Derbyshire Peak District National Park.

[@jaytomson7052]

This is very educational for myself, being a new 850 Mk3 owner. Thanks.

[@TornadoCAN99]

I've had a stuck throttle on a concentric on my Commando....happened after a spirited ride on a hot day. Stopped for fuel, preparing to kick it, gave the throttle a quick full open twist as I always do be habit, and the grip did not return to closed. Tried jiggling the grip, cables etc and nothing got it to close. While fiddling with the carbs I noticed the fuel bowl was too hot to touch with bare fingers. Then after a few more moments, I heard the slider slam shut again. I put this down to heat soak while stationary at the pump from head into carb giving thermal expansion and slider jamming wide open. I fitted the thicker type Tufnol spacer between manifold and head and also gave the carb slide bore a light honing with very fine emery paper/oil. Never happened again. In your case, I'd suspect the flange ears might be too tight, giving some distortion high up in the bore Or perhaps a throttle cable or the splitter is sticky (lubricate cables with light oil and grease for the splitter box is best). Or the cable might be routed poorly, excessive bend somewhere.

[@stefansikora5183]

The light honing with emerald paper did the trick for me as well. I marked the circumference of the throttle slides with a pen marker, dropped the slides in the bodys and checked where the marks got wiped off.

[@briancooper562]

I had a couple of IT Yamaha both of which had the throttle jam open and it was ice. As soon as heat from the engine/exhaust heated the carb it freed. This was cold weather and some water in the fuel due to condensation, Evaporation of fuel in the carb reduced the temperature enough to freeze the carb open. Bye the way I know where you live. Missed any B-17 recently?

[@Chris.rooke150]

Ha! Indeed I wasn't able to attend the Mi Amigo remembrance service this year due to a sudden family bereavement. 😒 Hopefully be back next year. 🤞

[@martinowl]

That must have been a tad concerning when the throttle stuck open 😱. Thankfully it sorted itself out ok. Easily the best looking machine at Moneyash.

[@Chris.rooke150]

Thanks! 👍

[@TornadoCAN99]

Regarding anti wet sump setups, I prefer a manual oil tap with an ignition cut off micro switch. These cannot go wrong and when open they give full oil flow. The spring type ball valves are marginal at best....the gear type pump on Commando develops very little suction effect, so any small grime in the ball spring operation might impede it. Also, because the ball stays in the path of oil flow even when off its sealing seat, it does reduce the flow down from max possible with the oil hose inner diameter. Feked in the UK sell a good oil tap with integrated ignition defeat switch. I made my own from some hardware store parts for under $15.

[@DaveFiggley]

Nice one, Chris. She's certainly a beauty. Is Santa going to bring you some teflon-coated throttle slides at Christmas? I must admit, I've never had a slide stick on either Monoblocs or Concentrics. All sorts of other issues but never that. The instruments must be Veglia by that time, yes? Nice and steady but I still have a special place in my heart for Smiths of Cricklewood. Is the four-speed box with the left foot lever still one up, three down? Maybe I'm confusing it with a Honda SS50. Great vid 👍

[@Chris.rooke150]

I believe that the clocks fitted to Commandos at that time were either Veglia or Smiths. It was pure chance which ones were fitted to which bikes - whatever was to hand on that particular day! Gearchange is normal: 1 down and 3 up. 👍

[@DaveFiggley]

@@Chris.rooke150 Well, the clocks on your bike say 'made in France'. They're definitely not Smiths but I thought Veglias were Italian. Was the Commando box ever one up, three down or am I imagining that? I test rode a VERY second hand one in the mid-eighties with the view to maybe buying it. It was a total heap but something sticks in my memory about the gear shifting. It was 40 -odd years ago so memory plays tricks but I'm fairly sure the gearchange was on the right, where it should be 🙂 Rather than pestering you I should probably just Google it. Cheers anyway.

[@bullitt79]

Those mischievous Amals!

[@donbrashsux]

They’re crappy

[@freemenofengland2880]

Although the throttle stuck open - You've still got kill-switch, ignition switch and petrol tap control. Lucky no one was following close.😉😜

[@kafkastrial8650]

Amal Carb bodies in time, are known to warp . Perhaps, a full throttle twist before starting may help to free it up?

[@rvdvogt]

No trouble with the cheaper Wassell carbs!!

[@pauldavies3764]

I fitted upgraded rectifier on my '76 and ignition light stopped working. Any ideas? Try correct starter earth lead from Andover,it certainly improved mine. Off into garage now to take oil out of sump.....and seeing yours means i need to get my solvoautosol out on mine!

[@TornadoCAN99]

The stock charge warning light I believe will not work correctly with a modern reg/rec unit. There is a note about this on the TriSpark troubleshooting web page. There are alternative voltage monitor warning LED's etc available that work and look stock for the bike. Look up "Improving Classic Motorcycles" in the UK for some solutions.

[@pauldavies3764]

Thanks,i will look into that,although i am considering selling bike.

[@-old-school-motorcyclesltd]

Very scary I would have gone straight home on low speed 😊😊 Frightening absolutely at least you got home in one piece that’s the main Atb phil

[@paulsilson2148]

The last video I watched of yours you had bike trouble as well, not much luck, enjoyed your video

[@Chris.rooke150]

I think that both problems stemmed from lack of use, I'm afraid. 😒

[@paulsilson2148]

@@Chris.rooke150 o boy

[@paulsilson2148]

@@Chris.rooke150 use more often I guess

[@tokairic3925]

@@Chris.rooke150 Too right - when we used our bikes daily and didn't parade them about once a month we didn't have so much hassle. Use and maintain correctly and often.

[@pjofurey6239]

MIKUNI …..got sick of British carburettor cheese concentrics in the mid 80,s . Friends tell me the re-pop Amal’s are a different breed, but MIKUNI.