1972 Commando running issues - pls help a new owner.

Thanks Fritz for the info. I'm on the right path to better carbs!

Previously Fritz Wettstein wrote:

Previously richard_chan wrote:

From the Amal site, it is the only one i can find http://amalcarb.co.uk/throttle-slide-no-2-cutaway-zinc-26287.html

Have a look here: http://amalcarb.co.uk/mk-i-concentric-series/900-series/throttle-valves/hard-anodised.html

And for the single carb option: Item 252618903931 on ebay

Fritz

Thanks David for your feed back.

Re - Mikuni : this is mainly why IF i go with a single carb, Mikuni would be the weapon of choice. As i have used them on all my other bikes, seems stable and doesn't need constant attention.

I was advised by a father of a friend of mine, who has had a number of Nortons over the years, he has. Single mikuni carb set up because it is just stable and will run each and every time. He says the Amal always needs adjusting for some reason. And i can kind of see why he says that. When i was making adjustments , the bike was vibrating all over the place, and that the screws are not exactly snug fitting, even with the rubber washer sort of holding it in place.

As for the timing - the last attempt was done on wheels and off the stand, but not with someone sitting on it. I will try this and maybe the bike is more stable and check again. But so far, I'm shooting with the current result. At least it doesn't pop and bang like there's a firing range in the garage.

Previously david_evans wrote:

Single Mikuni is the better single carb option, fit and forget.

When you strobe the timing, do it with the bike stood on it's wheels not on the stand, get your buddy to straddle the bike and work the throttle. while you get down with the strobe (and ear defenders) as he briefly runs the bike up to 5000 you should see the mark move forward to the required setting. The will stop the mark and the bike jumping all over the garage.

Thanks John and Fritz for the repair suggestions.

My worry is this hairline crack next to the jet holder on the right carb.

I'll take another look at the carb after the easter holidays and take a photo and post it up. My concern is that it's not repairable. Which means new carb/s.

I've looked into the new Amal Premier more and leaning towards keeping it twin carb original looking. But TBC, i obviously wouldn't want to spend an extra 300+£ on new carbs if i didn't have to.

Thanks again John and Fritz.

Yup, will post luck as soon as i have time for the bike.

Re: Fritz - I'll send you a message here with my email either way first. My bike is a combat with 32mm 932 Amal.

Thanks guys. Hope you're having a good Easter Sunday! I just made a killer Lamb chop on the BBQ for my wife and little 2 yr old, was a winner

Thanks John for your reply.

Firstly, I made a few changes today.Aml Stay Up Floats - both sides set to 2mm bowl edge to the tip of the bowl when the needle is pushed down. Secondly - Clutch cable - had to install a new longer version, as I had new handlebar installed which needed longer cables. Thirdly - new braided Rocker Oil feed line. I checked, oil is running through it.I bring these up it's because only since I made these three changes, the bike has not idled consistently. Took a few good kicks to start, which was expected, as I had emptied the carbs. But when it started, it idled really low, so I let it idle for a bit while I was claeaning etc, but it started idling lower and it died.Kicked it over again, idled ok, let it idle, it stayed idled for a bit, then died. Then I turned the idle screws on both carbs, turned it in 1/4 - 1/2, it idle ok, a bit on the high side of around 1500rpm, which is over the 900-1000rpm recommended (from memory). I then proceeded to turn the throttle cables out a bit, as it had too much play, but that still didnt fix it, it juts made the revs go up more. I took the bike out for a quick up and down the 20 meter path outside my garage, but when I got to the other end in 1st Gear, stop, clutch in etc, the bike decided to die. No cough, no back fire. But it kicks over and starts first kick.It's almost like it's out of fuel, but it isn't. I'm a bit lost here tbh... could it be the new clutch cable freeplay which i HAVEN'T adjusted as yet (mainly because I can't get the nut loose, and I'm way to sacred to use the electric impact gun on a smallish nut). The new cable is much tighter than the old one of course. And perhaps the floats are set too high? the manual recommends 0.21" from top of bowl to float when it's sitting?Thanks for any suggestions.

Rich.

Previously john_holmes wrote:

That crack looks very like the casting defect that is close by and possibly not a crack at all, I would take some emery paper to it to level it off and follow up with a polish. If it still shows as a black line after the polish its a crack, if it has disappeared then it was a casting defect.

The slides look worn, they need replacing but if the bodies are ok then new anodised slides will stop the rapid wear, if the bodies are worn then resleeve.

What exactly do you mean by won't idle constantly, are the revs wandering say 900 to 1100, 900 to 1500, or does the engine die completely.

For the float height with the Stay Up Floats, i set it to 2mm as said in the Bushmans guide.

I measured the "regular" floats and they were easily just over 5mm.

I'll try and reset it back to the Andover's instruction tomorrow and see if it is any better and set idle at 1100 if i can. It was really idling great last week before the new floats. Back to the drawing board.

And for the nut, yeah, I'm going to give it a go as well, i guess I've gotta do it either way, as the cable is pretty tight.

Thx again.

Thanks David and Christopher for your reply.

No, I'm a German member, i have been in touch with the two very nice gentleman from NOC, who has given me some very good advice along with with members here.

Fritz has 2 right carb bobies i can purchase, but I'm going to give it one more go today and tune it as much as i can and take it out for a test ride if weather permits.

As for the float needles - they are the brass ones. But since the new stay up floats, the carbs have stopped leaking.

Back in a few hours of fiddling with result hopefully.

So figured out what i can.

Clutch didn't need adjustment after all, as i slackened the cable from the bar end, and the adjuster on the right side had a good 3mm play.

Redid the floats accordingly to the Andover info sheet. 0.17" when floats needle is closed.

Bike idle well between 1200-1300 at the moment.

Took it out for a test ride and it wasn't great.

Right exhaust is back firing constantly. And when I'm in 3rd gear, at 3500rpm, the bike seems to just gain life on its own and accelerate like it should have more power. But it pops even more in the right side.

On idle at traffic lights, the right pops as well.

I'm not 100% sure when in 3rd gear, the clutch is slipping, I've loosened the clutch cable so there is a good amount of play, but it didn't help.

Any ideas anyone why the rev shoots up in 3rd? The bike feels like it should have more power, but at the moment, it just bobs along ok.

Thanks everyone for being so patient with me and my newbie problems.

Rich.

Thanks is for your replies Davis and Julian.

One step forward and two steps back is the motto for the day.

I went back to try and balance the carbs again, found that the right side needle had fallen off the clip. Which could be why the right way on and off power.

But after reinstalling new clips, balancing and tuning it to stated, it ha s in fact worsened. It now back fires and shoots fire out the right exhaust.... Absolutely no idea why. Everything is in place as before.

The timing couldn't have gone out already. I haven't checked but I'm assuming no way timing is out as i only took the bike out 2 hours before and it ran okish.

Suggestions anyone?

Thx...

Never mind.

The right carb needle fell of the clip, therefore causing erratic throttle and pops.

Timing checked and all good again.

New problem is that in 3rd gear at 3000rpm, at slow throttle towards 4000rpm onwards it's fine. BUT, if i do a quick throttle twist at 3000rpm, the bike doesn't want to move, but the revs still climb up.

Clutch slip? It only happens in 3rd to 4th, and 4th gear as well.

Thanks Richard for your input on the Boyer. And John on the Clutch.

Questions tho - why would it only bog down or hit the wall in 3rd and 4th gear? I would think if it's an electronic issue, it would apply in any gear and revs would be bogged down in 1st and 2nd? Did you also experience this issue in higher gears?

The strange thing for me was that it would accelerate IF i turned the throttle slowly, and acceleration is slow, but steady. BUT IF i really open her up, the bogging starts between 3500 -4000rpm, and it catches up again at around 5000.

I looked at the wiring going up to the box, and the connection to the stator plate is in decent shape, but i have thought about upgrading to a Surefire, as i have read good reviews on them, and Joe from Norton GmbH have said they are basically the same unit but with the small issues solved.

Regarding the clutch - thanks both for your info. I have never had to use a belt sander on a bike before, this would be the first...

There is a regular drip of oil coming from the primary side at the moment, i will have to resolve this anyways, so it looks like my next job would be the clutch while I'm there.

Thanks again everyone, i hope this thread is useful to someone else one day, because I'm learning a lot here.

Previously richard_payne wrote:

Have you replaced the wiring from the Boyer stator to the ignition unit ? I do this every couple of years (I use ordinary household 2-core with a black outer insulation).

'Hitting a wall' at 3000 rpm is pretty characteristic of a pick-up wire that has broken inside the insulation (where it does a double bend through the back of the timing cover, about 1.5" up)

It is possible to have an adequate end-contact inside the insulation at low revs but at about 3000, when the engine really starts to leap around, the contact will intermittently make and break.

It can feel like carbs. The first time that it happened to me, I spent several happy hours at the roadside diagnosing all the wrong things. The second time, I recognised it immediately...and now I replace the cable regularly.

Taking out the clutch plates and scrubbing them in solvent every 10,000km or so is part and parcel of Commando ownership. It's unusual to find severe wear on the clutch friction surfaces but drive teeth do wear.