Will it start?

before you try to start it again make sure it hasnt wet sumped since you changed the oil this can happen in a few days on some nortons also the pilot jet bush is likely to be blocked if you have mk1 concentrics take a look at bushmans amal carb on the net,the timing marks you refer to are standard for a commando ,you will find with a boyer there is a drilling in the stator plate that you line up with the rotor for rough timing then once its running you have to strobe it at 5000 rpm hopefully this will have already been done before you bought it? dont even think about starting it without a full 12 volts in the battery as it will go on full advance and kick you back,the pistons should be flat top so it sounds like you have high compression ones fitted its a pity you dont know more about the condition of the engine from the previous owner if you get bored with it i will take it off your hands!!! best of luck regards nick

First thing Roger, please don't call a Norton a heap.

I agree with all that Nick suggested above, especially the full 12 V + if using an earlier Boyer, otherwise these are perfectly sound. And of course wet sumping makes kicking over a Commando more difficult, even more so in your case as it looks like your Mk2A has higher compression pistons. Having both, I can tell you there is no comparison between a 650 Norton and a Commando, especially an 850, so sorting it out to reduce the number of kicks will help lots.

Is your petrol fresh? Ideally use E0 BP Ultimate, unless you live in the South West or Murco Super, where supplied from their own refinery. The BP situation may change after April but not Murco. If you are using fuel contaminated with Ethanol and it has been in the tank for months, it may have suffered phase separation? (Putting water and Ethanol at the bottom of the tank....Eeeeeeeeeeeeeek)

To reduce the compression problem treat it as a big single, find compression with the kickstart but then instead of kicking keep a constant pressure on the kickstart and allow the compression to leak away slowly until you get a quick movement of the pedal as it goes over TDC. Stop just as this quick movement starts and then return the kickstart pedal to you preferred kicking postion and take your kick. As the compression has been released you can move the crank easily until the next compression, and as it will be moving at speed by that time the inertia in the crank will carry it through.

A freshly installed unstrobed Boyer using their holes in the stator plate will typically but ovr advanced, so you can try retarding it a few degrees to reduce risk of kickbacks. Strong boots with thick soles will spread the load of a kickback over a large area and reduce the pain

Judging by your questions on timing I guess you don't have a manual to refer to. You say the timing marks line up. As John says with the timing marks set at 28 degrees (before top dead center) line up the hole in the boyer with the screw on one of the magnets. Make sure you select the hole marked counter clockwise timing. To retard the timing for easier starting, rotate the plate anti clockwise. As the camshaft rotates at half the crank speed, 1 degree of ignition timing is half a degree of camshaft rotation. The plate diameter is 68mm so the circumference is 213mm so one degree of camshaft rotation (2 degrees at the crank) is 0.6mm at the edge of the timing plate (0.024" in old money) Roger so far?

When you get to strobe it, get a buddy to straddle the bike on the wheels not the center stand. He can control the throttle while you get an earful of raw power kneeling, praying to the strobe god.

Previously roger_johnson wrote:

Previously david_evans wrote:

Judging by your questions on timing I guess you don't have a manual to refer to. You say the timing marks line up. As John says with the timing marks set at 28 degrees (before top dead center) line up the hole in the boyer with the screw on one of the magnets. Make sure you select the hole marked counter clockwise timing. To retard the timing for easier starting, rotate the plate anti clockwise. As the camshaft rotates at half the crank speed, 1 degree of ignition timing is half a degree of camshaft rotation. The plate diameter is 68mm so the circumference is 213mm so one degree of camshaft rotation (2 degrees at the crank) is 0.6mm at the edge of the timing plate (0.024" in old money) Roger so far?

When you get to strobe it, get a buddy to straddle the bike on the wheels not the center stand. He can control the throttle while you get an earful of raw power kneeling, praying to the strobe god.

Hi David, Many thanks to you and others for very useful information but I have two new questions; 1] As I said before I have a spark but don't know what quality of spark I should expect. Again I have connected my car battery and then have 12.92V and a little less at the coils but still over 12V. The spark is white whereas doing the same with my kitcar fitted with an OMex 600 ECU has a nice snap to the spark and is blue. Something wrong here? 2] What manual do you suggest? I could not find a manual in the club's website which I would prefer to buy.

Many thanks Roger

1. Without being there I could not tell but a spark of some description should be enough and I have never seen a fat blue spark on mine but its a 2nd kick starter.

2. You can find the 71 factory manual here. There are others around

Previously roger_johnson wrote:

Previously david_evans wrote:

Judging by your questions on timing I guess you don't have a manual to refer to. You say the timing marks line up. As John says with the timing marks set at 28 degrees (before top dead center) line up the hole in the boyer with the screw on one of the magnets. Make sure you select the hole marked counter clockwise timing. To retard the timing for easier starting, rotate the plate anti clockwise. As the camshaft rotates at half the crank speed, 1 degree of ignition timing is half a degree of camshaft rotation. The plate diameter is 68mm so the circumference is 213mm so one degree of camshaft rotation (2 degrees at the crank) is 0.6mm at the edge of the timing plate (0.024" in old money) Roger so far?

When you get to strobe it, get a buddy to straddle the bike on the wheels not the center stand. He can control the throttle while you get an earful of raw power kneeling, praying to the strobe god.

Hi David, Many thanks to you and others for very useful information but I have two new questions; 1] As I said before I have a spark but don't know what quality of spark I should expect. Again I have connected my car battery and then have 12.92V and a little less at the coils but still over 12V. The spark is white whereas doing the same with my kitcar fitted with an OMex 600 ECU has a nice snap to the spark and is blue. Something wrong here? 2] What manual do you suggest? I could not find a manual in the club's website which I would prefer to buy.

Many thanks Roger

where abouts do you live? someone with norton commando know how with an hour to spare would probably set you right in no time! regards nick

1]Capacitor marked R-9H12V. 2CP [23W] witha dented case. 2CP is the twin capacitor pack fitted to twin coils but could be something else, a pic would help.

2]blue device which I have not yet removedmounted up near the rear of the oil tank.No idea Capacitor for running with flat or failed battery.

3]What I assume is a rectifier marked Luca 49072B 8027. Yes rectifier.

4] Two capacitors [condensors] not connected electrically, probably used with previous CB points set up? No idea why its got 2 capacitor packs for ignition, maybe one failed.

5]And what looks to me like a Ballast Resistor, I guess used to supply12V to the coils while starting? Yes not needed for Boyer

Why have you not looked in the online manual I posted the link too, most of this info is in there.

Go to my Monday post and click on the blue text

71 factory manual

And that will take you to the website