Ignition / Points - Norton Commando 750 (1971)

As instructed, I have the indicator set at 28 . I also have the AAU locked to full advance. However, there is no additional adjustment slack available to turn the plate clockwise enough to line things up.


This is my first Norton, so I’m new to this. From what I could figure out, the “Drive side” cylinder is the left, and it receives spark from the left set of points with the Black w/Yellow tracer wire. By the time the mark lines up, I’m at TDC.


Clearly I’m doing something wrong. I’ve checked with a bulb and I’m getting power to the points. I’m also getting spark at the plugs, just not at the right time. I’m getting gas and can smell the engine flooded after 10 kicks or so. And I’ve got compression. So, in my mind, if I can get the timing right, this should start.

I'm desperate for help. This motorcycle belonged to my childhood friend. He was the 2nd owner (since 1976). Sadly, he passed away Dec 7th, 2019. Right before he passed away he gave me this Norton. This is more than a bike to me, it is a constant reminder of a friendship spanning 50 years. I need to get this bike running.

I can't believe it won't start. I know he hadn't ridden it for about 6 years (cancer); however, he's a mechanic by training... auto, motorcycle, and FAA certified for planes... and owned his own shop for over 40 years. The gas tank had been drained, carbs looked great, all fluids were removed. What am I doing wrong??

CaptainBillK said:

I have the indicator set at 28 . I also have the AAU locked to full advance. However, there is no additional adjustment slack available to turn the plate clockwise enough to line things up.

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The AAU needs to be removed and repositioned to bring the timing back within the range of adjustment.

CaptainBillK said:

This is my first Norton, so I’m new to this. From what I could figure out, the “Drive side” cylinder is the left, and it receives spark from the left set of points with the Black w/Yellow tracer wire

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Yes.

CaptainBillK said:

By the time the mark lines up, I’m at TDC.

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Which mark? If you mean the scribed line on the points cam then that is for setting the points gaps, (0.015") it's not a timing mark. Edit: If you have been attempting to use the gap mark that would explain why you have been running out of ignition adjustment range.

FIRST... set the point gap.
2nd..... turn the motor forward ( 4th gear, bump the rear wheel) KEY ON...until you hear the plug fire. See where you are at on the degree scale.

The book shows a different alignment for the AAU than what I have. Now it won't let me post a picture. So, anyway, the manual shows that the AAU pivot pins are at the 11 and 5 o'clock positions. However, on my bike, they are at the 1 and 7 o'clock positions (you can see that in the pic on the right).

So, when I have the cam at 28 degrees, what am I lining up on the other side? I was trying to line up the point gap mark with the points. In the pics I already posted, you can see the left point plastic piece is not lined up with the mark on the cam. That's with the AAU at full advance and the cam at 28 degrees as shown in the first picture I posted.

CaptainBillK said:

The book shows a different alignment for the AAU than what I have.

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Which book? Which picture/diagram?

CaptainBillK said:

So, when I have the cam at 28 degrees, what am I lining up on the other side?

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You don't line up anything on the points side. The precise moment the points begin to open is when the rotor timing mark should align with the 28 degree BTDC mark (with the AAU fully advanced).

CaptainBillK said:

I was trying to line up the point gap mark with the points.

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Which, as previously stated is wrong.

After some book searching, I think perhaps what you could be referring to is picture 9 (10 & 11), page 119 of the Clymer Norton manual?

Edit: If so, then the points assembly shown in the accompanying photos is the later 10CA type.

Pull the whole assembly and start again. The AAU needs grease on every moving part. The points plate looks like new . Fine oil on the cam lube felts. Time it all using above posts. Condensers should be new too.

I was taught to use 2 washers to lock down the Points -AAU method. One big and one small. Go figure. So easiest to just buy a E.E. and forget about the fiddlings ? Life is short.

Are you sure you are locked in Full advance?

CaptainBILLK you are aware the cam runs backwards, ie counter clockwise? It kinda effects how you look at these things...

Pazon Sure Fire. Fit forget ride bissfully.

Loosen the center bolt on the ignition cam, pull it partway out and tap back-and-forth on the end until the plate pops off the taper. You can then reset it a few degrees in whatever direction necessary and start your setting process again.

I STILL run points and AAU on my Norton, and agree with what is in replies above. My method that I used last week:

Place bike in 4th gear, and have both plugs removed, but on cylinder so they are grounded and will spark with ignition on. Use rear wheel to turn engine over, and remember the AAU will turn CCW with rear wheel rotated for forward rotation. Take the advance unit off. Rotate rear wheel and set at 28 degrees BTDC. Verify which cylinder is on compression stroke, as both intake and exhaust tappets will be loose. Reinstall AAU, so that points for that cylinder are just beginning to open at full advance. (which on mine is halfway between the "scribe" mark used for setting gap at .015", and the "slot" on the points cam. I use a screw driver to turn advance unit CCW ... to force AAU to full advance. You can use washers to lock in place too. When you rotate the AAU that tiny bit to full advance, you should hear/see the spark plug for that cylinder spark ... or your test light come on. (depends on what your using.) I alternately use both.

The Norton one is a PITA for a novice to set properly; unlike a Triumph T140 or T120 which has a slot on the AAU you line up with a peg in exhaust cam. Why did Norton NOT do it this way? Probably cost, like most everything else ...

Wasn’t there something about cigarette paper just pulls from between the points at timing mark? Been about 4 decades since I had points in a Commando. However on my ‘69 that’s my intention, so I need to pay attention here

illf8ed said:

Wasn’t there something about cigarette paper just pulls from between the points at timing mark? Been about 4 decades since I had points in a Commando. However on my ‘69 that’s my intention, so I need to pay attention here

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Yes, but if you have a strobe then it's far easier to just set the timing using the strobe as it's pointless (sorry!) spending time setting the static timing accurately if it can be checked with a strobe.

L.A.B. said:

Yes, but if you have a strobe then it's far easier to just set the timing using the strobe as it's pointless (sorry!) spending time setting the static timing accurately if it can be checked with a strobe.

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Ha Ha. I know and my ‘72 which is my rider currently has a TriSpark. The ‘69 is my museum bike, so as few modifications as possible.

And I do have a strobe. Bought this in 1971 for my ‘66 Ford Mustang.

And yes, I too use a timing light after my initial settings; for exact fine tuning. (As L.A.B and David input) ... just use a different 12VDC for timing light power though, IMO.

I rode my original 1971 Norton Commando as my daily transportation for several years and never set the timing other than using the cellophane wrapper of a pack of cigarettes to "set" the timing and never used anything but a matchbook cover to set the point gap. Bike ran great. Never had any issues with ignition or operation in general - in fact, I can't remember anything ever going wrong with the bike as far as a failure of any sort. Ran out of gas once but that was when I discovered that the "reserve" on my Roadster consisted of approx 1 cup of gasoline!