Need Help Setting Timing.

Hey Guys,

I know this is elementary but i need your help properly setting the timing on my '69 commando.

I can't get the bike up to 5,000 RPM's so i am trying to use the guide from on of the most recent Norton News booklets. A member wrote that at 3,000 RPM's the timing should be set at 23 degrees BTDC. Currently when strobing it shows 39 degrees at 3,000 RPM's.

Questions; Does the line on the rotor register at TDC or BTDC?

It's a '69 commando with the boyer installed in the back of the timing side (like an atlas). I did set the initial timing to 31 degrees BTDC. I'm confident that i don't know how to properly set the timing and any advice and direction you can provide will be much appreciated.

jsouthard said:

I can't get the bike up to 5,000 RPM's so i am trying to use the guide from on of the most recent Norton News booklets. A member wrote that at 3,000 RPM's the timing should be set at 23 degrees BTDC. Currently when strobing it shows 39 degrees at 3,000 RPM's.

Questions; Does the line on the rotor register at TDC or BTDC?

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Are there one or two timing marks on the alternator rotor?

If there are two marks 180 degrees apart, then only one will be the correct timing mark, the other mark can be ignored.

Remove the spark plugs, then turn the crankshaft in the normal direction of rotation until the pistons are approximately at TDC, then rotate the crank backwards until the first timing mark that appears in the primary timing aperture lines up with 31 degrees on the timing scale (or 28 degrees for points) the crankshaft should then be set to 31 deg. BTDC (full advance).

Your Commando's AAU rotates in the opposite direction to the usual Commando camshaft setup and you will be viewing it from the left hand side therefore the paintmark on the Boyer rotor must be aligned with the clockwise rotation hole in the pickup plate once the crank has been set to the 31 deg. BTDC position.

L.A.B. said:

Are there one or two timing marks on the alternator rotor?

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Thanks L.A.B.,

It's a single marking. Sparx 3 Rotor Stator.

I have the one marking set to the 31 degrees and aligning the rotor to the proper hole. The problem is that once warmed up at at high revs it still seems to be out of time.

With the strobe should the single timing mark on the rotor line up with the 31 degrees at 5,000 RPM's or do i need to create an additional mark for BTDC?

jsouthard said:

With the strobe should the single timing mark on the rotor line up with the 31 degrees at 5,000 RPM's

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Yes, as you increase the revs, the strobe should show the timing mark advancing along the timing scale until at around 5,000 RPM it should be level with 31 degrees.

If the engine won't reach 5,000 RPM without any load then either the timing is way off, or something else seems wrong. If the rotor mark is reaching 39 degrees by 3,000 RPM then the timing would seem to be too far advanced.

I thought all Sparx alternator rotors had two marks same as late Lucas rotors.

jsouthard said:

do i need to create an additional mark for BTDC?

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I don't quite follow your thinking, as I can't see why you think you would need any additional timing marks?

It is showing 39 degrees at 3,000 RPM's with the strobe.

With the points in the back do i move clockwise or counter clockwise to retard?

jsouthard said:

It is showing 39 degrees at 3,000 RPM's with the strobe.

With the points in the back do i move clockwise or counter clockwise to retard?

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Clockwise to retard (when the AAU or EI rotor turns clockwise = rear points housing).

Thanks L.A.B.,

I'll dive in and see if i can get this figured out. I was very careful on setting the initial timing and am 100% confident that the rotor and plate are set to 31 degrees BTDC.

Not sure why i can't get it to make sense with the strobe. Thanks again.

jsouthard said:

Thanks L.A.B.,

I'll dive in and see if i can get this figured out. I was very careful on setting the initial timing and am 100% confident that the rotor and plate are set to 31 degrees BTDC.

Not sure why i can't get it to make sense with the strobe. Thanks again.

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Boyers are too crude in their backplate design and rotor gap to get anywhere near 10 degrees at best on static setting. That's why you have to do the dynamic adjustment by strobe. I prefer to set the static a little on the retard side to assist the kick starting and then gradually adjust the advance until the strobe hits 31 at 5000.

Mick

I'm about to install a micro-MKIII myself shortly on my MKII Roadster.
Wonder if anyone with an electronic ignition system has ever compared the stroboscope readings for both R and L cylinder at a given RPM value ?
With contact points, you can adjust R against L, but how about a Boyer ignition ?

Paul

RedRooster said:

I'm about to install a micro-MKIII myself shortly on my MKII Roadster.
Wonder if anyone with an electronic ignition system has ever compared the stroboscope readings for both R and L cylinder at a given RPM value ?
With contact points, you can adjust R against L, but how about a Boyer ignition ?

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There shouldn't be any variation in timing between cylinders with a Boyer.

Get it into the ballpark , then fire it up and then adjust the plate in small increments by hand until test ride happiness ,no kickbacks and no pre-ignitions power loss. With that very early rear system I'd use new camchains then re-adjust after a break-in. :!:

I found recently when fitting a boyer ignition to my Matchless G15 - same timing arrangement as an early commando - that on the points housing the gap between the rotor and the trigger plate was too close, resulting in the rotor touching the solder joints in places on the back of the trigger plate. Do check that yours is not also doing this. I solved the problem by filing down the blobs of solder that stuck up the most amd also fitting a thick paper gasket behind the trigger plate.

This is an old thread from 2012.

Start at the recent post added by RedRooster (so information on a model with the points housing behind the cylinders doesn't apply).

Ah, Thanks L.A.B. I didn't look at he original date and assumed it was current as it was at the top of the heap of postings.

I don't use manufacturers' timing marks for either cam timing or ignition advance. For ignition timing I use a degree disc and pointer, find TDC with a broken spark plug and soap bubble, and then set up the Boyer to fire as per makers' instructions at the desired advance. Then I get the bike running and check the timing with the degree disc, pointer and strobe light. You need an aluminium degree disc on the end of the crank.

Once again, RedRooster wasn't asking "how" to set the timing, his question was about whether it's possible to get a variation in ignition timing between cylinders with a Boyer (which, at least theoretically, shouldn't happen).

acotrel said:

I don't use manufacturers' timing marks for either cam timing or ignition advance. For ignition timing I use a degree disc and pointer, find TDC with a broken spark plug and soap bubble, and then set up the Boyer to fire as per makers' instructions at the desired advance. Then I get the bike running and check the timing with the degree disc, pointer and strobe light. You need an aluminium degree disc on the end of the crank.

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Like L.A.B. said, my question was just about whether yes or no any variation can be expected between L and R, after conversion of the timing from points to Boyer.
Nevertheless, acotrel's info was very informative, as I had no clue how to detect the TDC via a simple means ! :idea: Thanks!
About the aluminium degree disk (I haven't yet opened my MK2 Roadster 850 yet to check), is this not supposed to be there as a standard ?
It is showing on a picture in my Owners Manual, that's why I assumed it was there... I will find it out shortly when carrying out the modif.

The reason for installing the Boyer is that four and a half years back, when kick-starting the Commando (after it had just been warming up previously, and was shut off again) for a second time, I had a kick-back, which caused some serous injury in my left foot (despite my motorcycle cross boots). I can still feel it today.
Ever since, I haven't driven the Commando, but now I really would like to drive her again (feeling this unique engine-sound again :mrgreen: ), but with no or very little risk on a kick-back.
Anyway, when cold, in the past, it never started from the first or second kick as apparently it should. With low battery it used to be a real nightmare) !
So there's for a little background on my Boyer project.

RedRooster said:

About the aluminium degree disk (I haven't yet opened my MK2 Roadster 850 yet to check), is this not supposed to be there as a standard ?
It is showing on a picture in my Owners Manual, that's why I assumed it was there... I will find it out shortly when carrying out the modif.

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What he is referring to is a timing or degree disc, not the timing scale.

Commando75 said:

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RedRooster said:

The reason for installing the Boyer is that four and a half years back, when kick-starting the Commando (after it had just been warming up previously, and was shut off again) for a second time, I had a kick-back, which caused some serous injury in my left foot (despite my motorcycle cross boots). I can still feel it today.
Ever since, I haven't driven the Commando, but now I really would like to drive her again (feeling this unique engine-sound again :mrgreen: ), but with no or very little risk on a kick-back.
Anyway, when cold, in the past, it never started from the first or second kick as apparently it should. With low battery it used to be a real nightmare) !

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In that case, replacing the points with a Boyer Micro-MkIII as you stated, may not be the best thing to do, as the old MkIII boxes are sensitive to low battery voltage which can result in kick-backs.
The Boyer MkIV or one of the other more modern electronic ignitions would perhaps be a better choice.

My 850 actually ran pretty good but never seemed quite right. Not smooth, idle too high, prone to kick back at start. So I finally did the TDC finding procedure as described on many threads on this forum. I tried rubber hose and then magnets to attach the degree wheel, but neither of those methods worked for me. The degree wheel would move slightly during the procedure. What did work was getting a wooden dowel rod and cutting off a short piece, whittling down one end a little so I could tap it into the rotor nut hole tightly. I then attached the degree wheel with a screw to the other end and it did not wander during the procedure. I made a spark plug stop as per the TDC finding threads.
What I found was that my timing scale was 6 degrees off, so I had been running 6 degrees too advanced. Now it runs much smoother, no kick backs, and just seems right. So it may well be worth the effort finding TDC on your bike.

mightydaj said:

My 850 actually ran pretty good but never seemed quite right. Not smooth, idle too high, prone to kick back at start. So I finally did the TDC finding procedure as described
What I found was that my timing scale was 6 degrees off, so I had been running 6 degrees too advanced. Now it runs much smoother, no kick backs, and just seems right. So it may well be worth the effort finding TDC on your bike.

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It would be well worth the effort of finding the TDC and ignition advance on all the cylinders on ANY bike, they can vary :!: :shock: