Setting Commando points

Is there a step by step video or something to setting points and timing? Is it magic?
I am no stranger to points, or even double sets but I cant seem to get it right on this thing.
I had points on all my old cars and even a double set on a Mustang I had. No issues.
A Kawasaki 900 with double points. (I did switch out to electronic ignition)
I cant seem to get this 71 750 sorted out.
I may be an idiot but I dont think so.
Yes, I do have a manual.
Yes I did a search.
Its just not clear to me.
Help?

I can detail you beyond your need to know with your back ground so likely your timing using wrong jug at TDC.
If starting ok but will not idle down then suspect the AAU is worn to stick in advance. Put at TDC and check which side has both rockers in slack then check the alternator rotor mark is the right one and get back if it is for next step to fail on. Use new or proven plugs and may have to get new condensors. A point mystery frustration was part of reason I left INOA forum and gained a well know Commando buddy so worked out great on my factory stock Trixie Combat. I jiggle back and forth once mostly dialed in so everything is about centered in adjustment range when done. a counitinuity test light very helpful. After a few happy rides can put time light on to please the forum inspectors. One little trick if you really like to hear the slow idle cam wearing beat is slightly offset each set of points a degree each side of 'perfect'.

Please feel free to detail me down to all the little details.
I have read most of the manual, including the part about twisting the points cam, it just doesnt seem to work out for me.
I know this is one of the main keys to getting the beast to run and idle properly.
I am the grasshopper.

Do you have a strobe?

Seems to me the workshop manual and also the rider's handbook goes through the timing pretty good. Which part don't you get? Need to know which jug is coming up on compression which you can tell by the exhaust valves. It's all in the book, and yes, you need a strobe, but a simple lamp and AAU advance holder will get you close enough to start it. It's easy to get the AAU 180 out too.

The problem with the points setup is the wear in the advance/retard cam. I set mine according to the book, (lock the cam with a washer, 28degrees etc) when I then strobed the timing it was running at 40 BTDC. What lead me to check with a strobe was the expensive result, cherry red down pipes and a cracked piston. Burnt a tank of oil in 140 miles. I don't think i would muck about with points again when there are so many other variables on a Commando that need dealing with.

Bin the points and change over to electronic ignition! I done this on my 850 back in about 1976 and have never looked under the points cover since! The electronic system, (mines Boyer) fires both plugs together as the 2 coils are wired in series so timing is always identical on both cylinders.

Magic.

What is not working out ? Are you not able to set both sides the same ? Are you running out of adjustment on one side ? Are your timing marks anywhere close to accurate (bum alternator rotor) ? Give us a little more to go on.

Greg

MikeM said:

Is there a step by step video or something to setting points and timing? Is it magic?
I am no stranger to points, or even double sets but I cant seem to get it right on this thing.
I had points on all my old cars and even a double set on a Mustang I had. No issues.
A Kawasaki 900 with double points. (I did switch out to electronic ignition)
I cant seem to get this 71 750 sorted out.
I may be an idiot but I dont think so.
Yes, I do have a manual.
Yes I did a search.
Its just not clear to me.
Help?

Click to expand...

You need to lock the Automatic Advance Unit to the fully advanced position.

Set point gaps first. You know the "master" point set is mounted directly to the breaker plate, time that one first. "slave" point set is on a sub-plate allowing independent timing after that.

Strobes are completely useless and grossly mis leading until wanting to know where the nicely set and running points end up on a dial AFTERwards.

Take off primary cover for ease of viewing w/o a dial in a hole in the way and to turn crank easy.

Push jugs to bottom and place degree wheel on for BDC-180' pointer or piston stops compromise method to find TDC or pressure balance at TDC, then rotate till crank in correct full advance degree's for your engine, either 28' Combat or 32' for all others and knife mark this on alternator stator resin for viewing though hole or wide open.

Critical to assure you are timing the ready to fire chamber that is near TDC with both rockers loose to know which jug is now sealed on compression stroke. Definitively mark the correct magnetic rotor cast in mark distinctly enough to see it and also good to mark a streak ahead of it on rotor face to alert ya its about to come around and slow up to creep up on mark.

Set AAU on taper loosely then put points plate on reasonable close guesimate point opening and use a probe to hold AAU in full adv to settle down plate but not the AAU so much it hang on tapper.

While holding AAU in full adv by probe or by fixing bolt/washer spacers, Put each set of points on their highest lift point and adjust the dwell gaps to .015"

Pick 1st jug to time with rockers indication, Set engine crank to correct full adv mark, put on test lamp [test it lights with points closed] and use small probe to twist AAU to full adv and then twist the whole trigger plate til light comes on. Repeat a few times to get consistent light with crank rotor/stator held still with full adv marks lined up then semi secure trigger breaker plate and do the other set and semi secure. If one set way out start over to best down dirty compromise and secure lightly.

Next is get AAU seated lightly on taper with rotor mark on fire position [until seated some on tapper AAU wiggles too much to set points by just ballpark for 1st attempt] while holding AAU in full adv with a probe or the bolt washers hassle, diddle breaker pivot timing slot till lights, on each set, then lightly nip it all down mostly stable and try to start.

If no joy repeat above till discovering your error over sights slip ups on nip downs till able to start and warm up with indicator test lamp off out the way of course.

Once warmed, diddle each point for best sound that side then double check the dwell gaps and if like me shift the whole mess about till this occurs pretty close to centered in all adjustmenter slots range, then start-warm and put timing light on and blip up to 4000's for good stable full advanced points activity to see where each point lands and fine tune further by ear of going by dial numbers you hope is right by now.

If seeing much extra sparks crawling over contacts as point open, can fine tune to extend contact life by various condensors though all point sets have about same surface area and lengths of wires to all land in similar functional range so often overlooked and not a big deal unless putting many 1000 mile on regularly.
















Set up a continuity test light so it lights when breakers contact then with point plate

concours said:

You know the "master" point set is mounted directly to the breaker plate, time that one first. "slave" point set is on a sub-plate allowing independent timing after that.

Click to expand...

Neither points set is mounted directly onto the back plate.
Both points sets are mounted on sub-plates-so each can be adjusted independently.

I think the lh point bolts to the back plate and the rh is adjustable on a separate mechanism..
The back plate is a loose fit in the housing so is always going to cause a problem [*^%$)(@###] if you don't set the lh points correctly first. Once the lh points gap is set an the backplate is secured approximately correctly [ Hobots method is good ] then get the other set of points correct.
Remember once you move the backplate it all turns to shit [*&^8#%***] and you have to start again setting the points gap etc
Comment above about points being fully adjustable is not correct for 1971 points.
When I rebuilt my 750 some time ago, I got my son on the timing light and he told me when the timing was right. I moved the back plate first to advance timing and he told me I had retarded it [*&^#*%T%&***}. That when I realised the problem mentioned above. Patience needed.
BTW, my 750 idles and runs very sweetly with the points ignition, whereas the boyer in my 850 is not so fine at low revs. The 750 is my show bike whereas the 850 is my workhorse.
Good luck
Dereck

kerinorton said:

I think the lh point bolts to the back plate and the rh is adjustable on a separate mechanism..

Click to expand...

No, neither the early (6CA) or late (10CA) points assemblies has a "fixed" points set.

http://www.classicbike.biz/Norton/Repai ... mmando.pdf
Section C40

L.A.B. said:

Do you have a strobe?

Click to expand...

Yes I do have a strobe.

MikeM said:

L.A.B. said:

Do you have a strobe?

Click to expand...

Yes I do have a strobe.

Click to expand...

So, have you used it to check the timing on each cylinder yet?
If so, what was the result?
Did you check (and adjust if necessary) the points gaps?

All of my experience setting timing on points has been on a Triumph but the principals are the same. You may not have to bother with setting the static timing if you can get it running and strobe adjust it right away. Before you start check the wire colors from the points to the coils to double check which set of points are firing which cylinder.
Then make sure each point set is gapped correctly using the mark on the cam. Loosen locking screw 6 and turn eccentric screw 7 as shown in this illlustration to adjust the gap. It doesn't show the numbers for the front set but they are the same just upside down.
The points have 3 places that you can adjust the timing. Each set of points can be adjusted on the plate using screws 4 and 5 and the entire plate adjusts on the pillar bolts. Set each set of points in the middle of their adjustment range by loosening both #4 screws and turning the eccentric #5 screw. Also, loosen the pillar bolts and put the plate in the middle of its range lock everything down. Now try to start the bike and there is a good chance it will start up. Do not ride it! Get the strobe on it right away. You don't even want to warm it up, as you only need to go to about 2500 rpm with points to get full advance. Watch out for kick back when trying to start it as a may be a little advanced.
Put the strobe first on the plug wire firing from the rear set of points. Loosen the pillar bolts and rotate the entire plate slightly until the timing marks line up at 2500 rpm. Now switch the strobe to the other side and and loosen the #4 screws and turn the #5 eccentric screw on front set until the marks line up for that side. Tighten everything up good, job done. You can check how well the centrifugal advance is working by watching the marks move under the strobe as you rev up from idle to 2500, should be a fairly steady smooth advance.
This all assumes your carb and valves settings are good and the bike doesn't have any starting issues. If it won't start then you need to go through the static timing steps in the work book.
EI is nice but points work fine and are more tolerant of bad batteries and dodgy wiring. You do need to adjust them about once a year though as the plactic heel wears.

Nobody has mentioned the small washer that keeps it on full advanced is it not needed?

J

The washer has been mentioned several times. I called it the 'advance holder' in the 4th post here. I still say the instructions in the books are clear. Also remember the spark happens when the points open.

auldblue said:

Nobody has mentioned the small washer that keeps it on full advanced is it not needed?

J

Click to expand...

I've never used the extra washer to clamp the AAU in the advanced position. I think it's less accurate doing it that way. Clearance between the cam and its spindle allows room for error. You could clamp it in several different positions, all fully advanced. I just twist the AAU cam to fully advanced, and see if the points just open when it gets to full advance.