Setting up my timing

Hey I am just wondering if I am on the right track here.


I assume the "firing stroke and the compression stroke are the same thing just different names".



First I have to rotate the motor and check the point gap (.015) on both sets of points when the little mark is at the nylon runner

I have to set the points plate to the middle of the elongated slots.

Then as I'm on the compression stroke on the right cylinder I watch the timing marks on the rotor until they get to 28 degrees BTDC then stop rotating the motor.

Then I make sure the right hand set of points open at that exact moment.


Then I can do the same thing to the left had side.

Dave
You will need the cupped washer tool to hold the advance springs to fully advanced. Do you have this tool???
Also a bulb 12 volt with wires and alligator clips and a battery are necessary to help in getting the points just right. Use your Workshop manual...its your bible to keep your Norton running right.
CNN

Well...I dont have the cupped washer, but i have a regular one, the shop manual says that is ok too I also have an multimeter the makes a tone when there is continuity so that should be good. I also have a workshop manual but it is older and does not explain the timing that well..... I have read the PDF (online manual) posted on this website and it is much more clear then my book.


Sorry for my limited knowledge. The points cam can be rotated into any position when you first put it in....how do I know where to put it in??? is there any trick like a little mark lining up with another mark at TDC or something??????anything???? that seems to be the hardest part. Once I know where that cam sits I should be able to figure it out. Because , unless i just dont get it (could very well be) a guy will advance and retard the timing by rotating the cam forwards or backwards. So just because the timing is "out" doesn't mean that I should adjust the points plate it could just be the cam is in the wrong place????
Thanks guys!


Also what do you guys use to lubricate the auto advance ??

DaveK said:

I assume the "firing stroke and the compression stroke are the same thing just different names".

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They are actually separate strokes, but the ignition actually BEGINS firing @ 28° BTDC (before top dead center) compression, and leads into the ignition stroke. You have to ignite the mixture before you can drive the piston down. Also you can always remember the 4-strokes as Suck Squeeze Bang Blow, i remember that from High School!

If your going to live with an AA unit you need you take it out get it in your hands. Than clean it, lube it, and check it for wear. New springs are good, on BSA's we often use stronger springs because they can prevent pinging. It's common to find little dents in the slots at full advance and if they get too deep the damage will keep the unit at full advance for random amounts of time, tough to fix. This wear and the cost of the new unit are what drive the E.I. market.
Now replacing the A.A. unit into the cam taper and getting it just right is the key to the whole job. After that you just need to fine tune each side. Your volt meter (or a light) just gets you close enough to run the bike, strobe timing gets them running the way they were intended to run. Mastering the fine adjustments without mangling the point parts and adjustment hardware needs a good gunsmith type screw driver head, lots of practice and patience. It’s most important that you gain an understanding of how the sum of the parts makes a brain of sorts. If you keep just looking at it as a pile of parts and tweaking on it the system will not respond well. An old hand can fix them on the side of the road in minutes in the dark but a newbie can spend days and never truly understand the effect of the last adjustment. Be glad you don’t own a triple.

DaveK said:

Sorry for my limited knowledge. The points cam can be rotated into any position when you first put it in....how do I know where to put it in??? is there any trick like a little mark lining up with another mark at TDC or something??????anything???? that seems to be the hardest part.

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It's been 25 years or more since I did this, but this is what I remember...

Set the points plate centered in its adjustment range. Lightly seat the AAU taper into the cam and rotate it until the notch in the points cam aligns with one of the points rubbing blocks. Set the gap to .015 and repeat for the other set.

Turn the engine over slowly while feeling for compression on the right plug hole. Then creep the crankshaft (bumping the rear wheel forward in 4th gear works best for me) until the timing marks are at 28 BTDC. Rotate the AAU clockwise until the right points just open. You need to keep the weights extended while doing that. Now you can snug the AAU bolt and lock the taper in.

Remove the bolt, install the locking washer to hold the cam fully advanced. Rotate the points plate clockwise until the right points close, and then slowly counterclockwise until they open again.

Start up and set timing with a strobe.

Also what do you guys use to lubricate the auto advance ??

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Doesn't matter, whatever you use will fling off anyway. The felt wicks on each set of points can be soaked in light machine oil however to lube the points cam.

I am the same as Maylar
I changed my Commando over to electronic ignition along time ago and never looked back. All I would would suggest is to get Mick Hemmings Engine Rebuild DVD. He will walk through the process of Points as well as EI setup.
CNN

Hey guys , thanks for all your help. I was able to get it timed. It is a "dumb" system that there is no starting point for the cam, I just sorta guessed and the rest I did by rotating the points cam. I suppose that you could mark the AAU where it fits into the taper when you take it apart.

On another note, there is a bit of play between the shaft key and the rotor which causes the rotor to move a bit, I suppose this would cause the timing to be somewhat unreliable. I just split the differance and torqued the rotor down.

Thanks again guys

DaveK said:

On another note, there is a bit of play between the shaft key and the rotor which causes the rotor to move a bit, I suppose this would cause the timing to be somewhat unreliable. I just split the differance and torqued the rotor down.

Thanks again guys

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Are you referring to the camshaft sprocket key? Going by memory I can't think of any other key. It should be tight. There were some cams that had the keyway cut inaccurately in the wrong spot which made it impossible to time both sides. The solution was a step key or a vernier sprocket.

The auto advance cam itself has to be locked in the fully advanced position for setting the timing but make sure your bob weights haven't been slammed against the slot in the backing plate enough times to elongate those slots (very common) because then you'll be setting it too far advanced.

RennieK said:

The auto advance cam itself has to be locked in the fully advanced position for setting the timing but make sure your bob weights haven't been slammed against the slot in the backing plate enough times to elongate those slots (very common) because then you'll be setting it too far advanced.

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I suspect that if the bob weights were available as replacement parts there'd be a lot more people running points ignitions. Too bad they weren't hardened to prevent wear in the slots. Mine were pretty worn out within 5 years of new.

A guy could put a little dab of weld on the end and solve that problem, apparently a little extra advance isn't a problem because I have a Norris D cam.

The trouble is the slots keep getting bigger and bigger. The newly carved slot extensions aren't as wide or smooth as the original slots and the weights bind and stay up in the new area so your timing is always advanced. Weld would fix it though.