Commando running advice

I sense lots of helpful advice from different people coming your way!

To begin with, as if you didn't know this already, you need to be sure that the charging system and battery's good (I've always been a fan of installing an ammeter if you don't have one already), the ignition timing's good, you're getting a fat blue spark at the plugs, the valve clearances are good, the air filter isn't clogged â all the basics. Then ...

The first problem seems odd to me. All I can say is, I have Boyer electronic ignition, which is sensitive to inadequate voltage, and an alarm, which is a constant drain on the battery except when I switch it off to ride the bike, and my bike is usually a first-kick starter even after leaving it several days. But this problem might be linked to the second.

The second problem is easier for me to advise on. 1,700rpm is a very fast tickover, figures under 1,000rpm are mentioned, but I've never had a 100% reliable tickover either (although I think I'm getting close), and consider 1,000rpm good for my bike. Depending on how old the carbs are, you might consider replacing them: they have quite a limited life, and you might be surprised how differently they behave if, for example, you simply replaced the throttle slides. About giving them some TLC, rebuilding them, or ensuring that all the jets and other internal parts are correct, a good place to start would be here: http://www.jba.bc.ca/Bushmans%20Carb%20Tuning.html#6SYNCH â this is also invaluable: https://www.princeton.edu/ssp/65-cub-data/library/amalbritbike.pdf â I have recently had a very disappointing experience with Burlen's new 'Stay Up' floats for Amal carburettors, so until I hear back from Burlen about it I would advise against trying them. Cutting out when turning is, in my experience, possibly down to incorrect throttle cable routing, but that usually leads to the engine revving, and I would put my money on a broken electrical wire somewhere: turning the bars stresses the wiring in that area to some extent even when it's correctly routed, and if there's a wire that's broken but makes contact when relaxed, as soon as it's stressed it'll open up and the circuit is broken.

About the third problem, this might or might not prove to be very expensive. Classically, jumping out of gear is about worn dogs on gears, but there can be other causes. You need to strip the gearbox down and inspect all the parts closely. It's principally the gears that are expensive to replace. You might check out my experience this summer in this thread: http://www.nortonownersclub.org/noc-chat/technical4-commando-forum/610591450 One key thing in the gearbox is, if you have a ball bearing on the inner end of the layshaft, you need to replace it with a roller bearing, available for example from Andover Norton.

Good luck, there are people on this forum who are much better informed than I, and I look forward to the day when you have all these problems sorted! Cheers.

I would spend some time with a carb balancer and try and improve on the tickover speed and stability. Even worn carbs should be able to be tuned to give about 1000 rpm. Worth a shot before shelling out on new carbs. New slides might give you some improvement but consider putting that money towards new premiers.

For starting, do you tickle the carbs (till they flood)? or use the choke?

The gearbox may just be a case of the gears not being fully engaged and a fix may be a new selector spring and careful attention to the quadrant/camplate timing.

Not running below 1700 signifies blocked pilot jets, you clean them out with a 16 thou drill mounted in a WD40 plastic tube. The pilot air and fuel circuits will also need attention if the carbs have not been cleaned for sometime, blame the ethanol in the fuel.

Starting more difficult after the longer it stands sounds a bit like wet sumping. Drain the oil from the sump after several days of non use. (Just before starting) There may be more in there than you think so have a big tub handy. Also, leave the engine on compression when parked, this will slow down the sumping process.

You are correct, John, What a mess ethanol leaves. Use Esso Supreme Synergy+ if you live outside one of the three UK ethanol zones. I was delighted to find that EVF Super unleaded in the IOM is E0, also and suspect BP ultimate is too but BP won't admit to selling ethanol free. Politics for you...

Previously Neil Wyatt wrote:

Starting more difficult after the longer it stands sounds a bit like wet sumping. Drain the oil from the sump after several days of non use. (Just before starting) There may be more in there than you think so have a big tub handy. Also, leave the engine on compression when parked, this will slow down the sumping process.

You are correct, John, What a mess ethanol leaves. Use Esso Supreme Synergy+ if you live outside one of the three UK ethanol zones. I was delighted to find that EVF Super unleaded in the IOM is E0, also and suspect BP ultimate is too but BP won't admit to selling ethanol free. Politics for you...

Can't remember which IOM EVF station it was but one had the super unleaded pump with an EN228 sticker on, the one I used at Ramsey was labelled correctly for E0.

We used IOM evf fuel in 3 bikes and left the tap leaking and plug fouling issues in the mainland. Not that we didn't have problems!, but managed to keep all three going . The old body suffered most ,the TT classic wax jacket was not even showerproof, and the clip ons with bumpy Manx backroads did the wrists some mischief, as did a dozen laps of jurby on the Ducati. Thats the price of fun.

Hello Keith

sounds like someone has been compensating for gunged up pilot jets by raising the throttle slides, deposits build up over time so as John said a good clean out wont do any harm and should restore normality as even when worn amals work pretty well usually the only detriment is to the fuel consumption

Have a look at Old Brits Norton, technical articals.

Previously john_holmes wrote:

Previously Neil Wyatt wrote:

Starting more difficult after the longer it stands sounds a bit like wet sumping. Drain the oil from the sump after several days of non use. (Just before starting) There may be more in there than you think so have a big tub handy. Also, leave the engine on compression when parked, this will slow down the sumping process.

You are correct, John, What a mess ethanol leaves. Use Esso Supreme Synergy+ if you live outside one of the three UK ethanol zones. I was delighted to find that EVF Super unleaded in the IOM is E0, also and suspect BP ultimate is too but BP won't admit to selling ethanol free. Politics for you...

Can't remember which IOM EVF station it was but one had the super unleaded pump with an EN228 sticker on, the one I used at Ramsey was labelled correctly for E0.

Yes John, the EVF in Ramsey I was using labelled the Super as BS7800, a standard that could mean 0 ethanol or up to 5%. The standard for 0 ethanol unleaded is BS 7070 and you rarely see it. I accidentally spilt some of this BS 7800 on my tank and the paint did not come away on the tissue. It would have if it was EN228.