Timing "74" 850 w/[xxxxx] BOYER ignition for the mechanically challenged.

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CraigT

CraigT

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I recently got a 74 Commando that has a Boyer Bransden NT1a ignition. I want to learn how to set the timing. I should start by saying that I'm not an experienced mechanic in this area but I want to learn.
Can anyone direct me to or explain in clear and easy to understand layman's terms, all the steps to do a static timing test and adjustment?
I have the plugs out, the timing cover off and unscrewed the little cover for the view of the markings (on the left...is it the alternator or flywheel). I have an indicator light ready at hand as well. Thanks so much!
 
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You're correct again....it's a Micro Digital. The pdf tells me nothing about setting the timing though. I really need a step by step on how to set the timing.
 
Use the MK3/4 instructions for timing, its the same as on the digital, steps 23 and 24.
 
CraigT said:
The pdf tells me nothing about setting the timing though.
Click to expand...

o_O
Micro-Digital:
http://www.boyerbransden.com/pdf/KIT00084.pdf

"5) Set engine at 31 B.T.D.C. on the alternator mark (ensure correct mark is used -there are two marks on the alternator on 1972/3 models, use the mark indicating T.D.C. with the pistons in top position).

6) Fit magnetic rotor unit using one of the bolts (supplied), with the magnets in line with the "NORTON" name on the timing case. See Fig.1.
[But do not tighten the bolt]

7) Fit stator plate (with the connecting wires at the bottom) using the standard studs.

8) The magnet on one side of the rotor should now be in the centre of the top timing hole in the stator plate; this should also set it half way along its adjustment slots. If not, move the rotor until this is achieved without turning the engine from 31deg. B.T.D.C. See Fig.2. [then, fully tighten the rotor bolt] (THE ATLAS ENGINE HAS THE POINTS HOUSING BEHIND THE CYLINDERHEAD, IT’S SHAFT IS ROTATING IN THE REVERSE DIRECTION.SET TIMING ON THE CLOCKWISE TIMING HOLE.)
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23) Start engine and time with a stroboscope to 31 B.T.D.C.(28 DEG.with standard ignition) with the engine running up to 5000 r.p.m. This is done by moving the ignition stator plate. If the timing is not obtainable before the end of the adjustment, the magnetic rotor will have to be slackened off and moved a small amount until the correct timing can be obtained."
 
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The rotor and pickup installation instructions get you "static" timing that should be close enough to start the engine. Once running, you use a timing light (stroboscope) clipped to either spark plug lead. Have someone else hold the throttle and bring up the revs while you watch the timing marks. The rotating mark is on the alternator rotor, the degree scale is attached to the primary cover - visible through that inspection hole. Timing is adjusted by rotating the pickup plate (loosen the pillar studs), clockwise will advance it. Ultimately you want to read 31° BTDC at 5000 rpm. It's a bit nerve wracking to do that with the Norton wanting to dance across your garage floor... put a carpet under the center stand.

HTH
 
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you will find in practice its difficult if not impossible to move the stator plate whilst the engine is running to align timing marks. Mark the stator and timing cover with pencil or whatever . Slacken the two bolts slightly and then move the stataor plate clockwise to adv and anticlock to retard. roughly 1/100 of inch is one real degree the timing cover mark is a ref point .
By all means run the engine up and strobe but if say it needs 5 degrees then stop engine . slacken bolts and move plate roughly 1/20th inch
I have always set Boyers so the bike kicks back very occaisonally when starting on k/s. With es of course I would retard a fraction more to guard against this eventuality.
If you have a modded engine and want to set up for max power then off to the dyno_Or find a suitable stretch of road and experiment . but do not advance beyond the very occaisonal kick back. That is just about 31 . If it kicks back most of time then it is 36 .. Despite what Boyer say about 31 have always found engine seems sweetest at about 28.
 
oldmikew said:
you will find in practice its difficult if not impossible to move the stator plate whilst the engine is running to align timing marks.
Click to expand...

I've never found it to be at all difficult and certainly not impossible to adjust the stator plate whilst the engine is running.
 
L.A.B. said:
o_O
Micro-Digital:
http://www.boyerbransden.com/pdf/KIT00084.pdf

"5) Set engine at 31 B.T.D.C. on the alternator mark (ensure correct mark is used -there are two marks on the alternator on 1972/3 models, use the mark indicating T.D.C. with the pistons in top position).

6) Fit magnetic rotor unit using one of the bolts (supplied), with the magnets in line with the "NORTON" name on the timing case. See Fig.1.
[But do not tighten the bolt]

7) Fit stator plate (with the connecting wires at the bottom) using the standard studs.

8) The magnet on one side of the rotor should now be in the centre of the top timing hole in the stator plate; this should also set it half way along its adjustment slots. If not, move the rotor until this is achieved without turning the engine from 31deg. B.T.D.C. See Fig.2. [then, fully tighten the rotor bolt] (THE ATLAS ENGINE HAS THE POINTS HOUSING BEHIND THE CYLINDERHEAD, IT’S SHAFT IS ROTATING IN THE REVERSE DIRECTION.SET TIMING ON THE CLOCKWISE TIMING HOLE.)
.
.

23) Start engine and time with a stroboscope to 31 B.T.D.C.(28 DEG.with standard ignition) with the engine running up to 5000 r.p.m. This is done by moving the ignition stator plate. If the timing is not obtainable before the end of the adjustment, the magnetic rotor will have to be slackened off and moved a small amount until the correct timing can be obtained."
Click to expand...
Great, just what I needed....mine is a "74", are there two marks on the alternator as well?
 
maylar said:
The rotor and pickup installation instructions get you "static" timing that should be close enough to start the engine. Once running, you use a timing light (stroboscope) clipped to either spark plug lead. Have someone else hold the throttle and bring up the revs while you watch the timing marks. The rotating mark is on the alternator rotor, the degree scale is attached to the primary cover - visible through that inspection hole. Timing is adjusted by rotating the pickup plate (loosen the pillar studs), clockwise will advance it. Ultimately you want to read 31° BTDC at 5000 rpm. It's a bit nerve wracking to do that with the Norton wanting to dance across your garage floor... put a carpet under the center stand.

HTH
Click to expand...
Awesome advice!
 
CraigT said:
Great, just what I needed....mine is a "74", are there two marks on the alternator as well?
Click to expand...

Yes, late alternator rotors have two marks 180 degrees apart so it's the mark that appears in the timing aperture when the pistons are approaching TDC.
 
I marked my rotor with a black sharpie and white fine line paint pen when I figured out which side to use. It's the one opposite from the key slot.
 
Not sure if the OP needed procedure for determining if the timing scale on his primary cover are accurate? This is done by removing the outer cover and attaching a timing degree wheel to the alternator rotor. Rig up a pointer wire and get left side piston at compression stroke. Using a piston stop device (I made mine by knocking out ceramic of old spark plug and fitting a length of steel rod/old wheel spoke through the plug casing and embedding in epoxy to hold rod). Rotate engine using rear wheel while in gear until piston contacts the stop note degree wheel pointer location. Rotate engine the other direction until piston again comes to a stop and note that degree position find the mid degree point between those two positions. That is TDC. Now place engine so it's at 31 BTDC or where you want to set ignition advance to. Now without touching engine rotation remove degree wheel and fit primary cover to see where the degree gauge lines up with timing. Mark on the rotor. This lets you know how far away the gauge may be from reality. Mine was a couple degrees off.
 
It's tons easier with two people; one person to shoot the strobe on the drive side and another on the timing side to rotate the plate. Took me three tries to get it set right by myself. Good news; the one on the other bike was set 35 years ago and hasn't been touched since.
 
Used the advice I got from everyone and got her running consistant and smooth. Thanks for your help!!
 
Thanks for all the previous advice with timing, carb related and clutch! Now i have a new issue. I did the timing and got the Norton running pretty nice. Went for a few test rides, no problems until today. Today I took it for a short test ride, maybe 2miles up and down hills, (typical Pittsburgh variety) came back to my place and let it idle for a bit while I checked for oil leaks. The bike idled nice for about 3-4 minuets then suddenly died. Turns out it had fouled the plugs (one is wet and black and the other just black). Put new plugs in, and it runs great again. Go for another test ride. Running okay but after about a mile, I could tell it wanted to die....had to keep revving engine to keep it running.....finally just dies....will not start, even on a very long steep downhill (trying to roll start in second gear). Back to shop, removed plugs and one is wet and black, the other just black, just like before. I put brand new plugs in and now, absolutely no spark at all. I'm pretty confused and don't really know how to proceed. I'm guessing there is a standard chain of tests to identify where the problem is, can anyone help me here? A couple things I should mention, the battery and fuse are fine. All the other electrical like lights, horn, turn are working as normal. One thing I did notice but I cant see how it could have affected anything......my battery tender lead (the part that plugs into the lead from the charger) got wedged between the frame and the primary case.... and the pressure of the engine cut through the rubber encasing the end plug part of the lead......it appears, from examination, that it only cut the positive side.....so I don't think there was a short since the frame is positive ground. I did continuity test on the lead to make sure all is in order and it seems to be working as it should.
 
By wet plug do you mean wet with black oil or wet with fuel?

Can you do a throttle blip test on the warm/hot engine while watching the exhaust out the silencers to check for puffs of oil smoke (blue usually)? I had one side puffing blue when blipping throttle and that plug was wet oily black. Turned out to be a failed 45+ year old intake valve seal. I replaced both side seal with new KibbleWhite viton seals using a method not requiring head removal. Solved that for me. Note this was not so bad as to cause engine stopping. Your situation may be worse or something else happening.
 
Tornado said:
By wet plug do you mean wet with black oil or wet with fuel?

Can you do a throttle blip test on the warm/hot engine while watching the exhaust out the silencers to check for puffs of oil smoke (blue usually)? I had one side puffing blue when blipping throttle and that plug was wet oily black. Turned out to be a failed 45+ year old intake valve seal. I replaced both side seal with new KibbleWhite viton seals using a method not requiring head removal. Solved that for me. Note this was not so bad as to cause engine stopping. Your situation may be worse or something else happening.
Click to expand...
Thanks for your reply but I don't get any spark at all...so any test of this sort is out of the question at this point.
 
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