Setting Commando points

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First you need to see if it rattles , then you have to start smokeing rolls ! . :D

RIGHT .

the stupid auto advance mechanism , FIRST . as first things first etc .
if it aint right , the silly contact breakers have no chance . SO one removes the A. A. Assy .

Theres a few shafts 7 bores that go over the shafts , for the bob weights , AND the Points Cam .
these all need to be clean like a babys bottom , so theres no rash . So are best cleaned in petrol or solvent.
Inspect the inside of the points cam to see it ungunged . Theres a REBATE there omewhere , To Hold the GREASE .
as being mechanical , its greased .

BUT , dry - you check the fit for SLACK . Radially . If theres more than two thou slack , its slack & wobly and unsatisfactory .
If theres five thou slack , its slack & wobbly and Most unsatisfactory . A BSA A65 ( & Id think A50 & A 70 ) Auto Adv. is 15 Degree .
Rather than 12 , so you get more RETARD , and a 500 rpm idle - if its necesary to bin it .

Checking the actions of ea. part individually , the bob weights should move freely , as should the main shaft / points cam .
No sticking or binding from burrs or galls. Or bent Shafts . So one gets a square and checks that alls square & true .

While your there , twiddling the bit it plugs into should tell you if theres a iota of rotary free play - which means the timing chains right ,
a mile of turn and the timing chains fallen off , on the way out , or needs adjusting .

While were at it , At the POINTS SETTING STAGE , We allways rotate Forward , or if you must back further then forward . So the take up is as it is running . Top Run Tensioned .

Now we can get nasty with the points . to Clean the faces , with a stone or wet & dry , you REMOVE THEM . So you get the face dead square and true etc . Then washem in solvent .
once youve done the square and true bit , unless a babboons been at it theyre unlikely to bend unless youve got a foul temper and a hammer .

The whole points plate , points mounting shafts etc is checked flat true square clean and burr free . A Hammer to flatten , a fine file to deburr . a flat face to hit it on , and a square
to see the shafts perpendicular . under good light . Whole trip should take a few hours if your going to enjoy it and have a cup of tea between steps to focus the focus . under good light .
Sit in the shade for the tea though.
Theres a silly wick there somewhere to . Bit archaic - but its for a drop of oil - which if you dismantle it occasionallys supurflous . BUT one GREASES the shafts . New horrible white nylon
points heals , an one smears the cam with grease , and whipes it so theres just residue. AND uses a tooth pick or match to pot a light bead along the heal . AFTER its run you just leave
a trace . If its dry new itll heat & evaporate . It must be greased to ' run in ' & harden the heal at the cam , and not run totally dry . Damp in theres adverse if its been bucketing down
or youve been through a river .

Now Where rthe Ciggarette Papers , tear / cut a 1/4 in. strip . Between the contacts if there shut its stuck . This get it as accurate as a strobe if your any good . You check it with that when youve finished
and itll tell you the rpms / advance . I ran 31 as I dont like hondas , but if your an old woman you can run 28 so it wont tryn throw you . MORE IMPORTANT is BOTH are EXACTLY the same 1/100th of a degree
which is accurate enough for mortals .

Therefore you set Ea point at 16 thou gap or watever it is . Rohan'l have a fit and say its twelve . But Whats important is the dwell .
THEN you get the ' turn ' right so with the crank at the right position , as you push the advance ( cam ) forward / thru Stationary
with say a screwsriver on a hard bit out , as it clicks on the stop , the paper s just come free . Not Before .

So its pretty basic , but not a 5 minute job . Magneto Twin takes 45 minutes if the points have been extracted & Faced . The 5 minute wankers bikes run like bandy legged girls .

The Contact Breaker Faces MUST be ' Flat ' together when closed . A tweak with needle nose plyers or somesuch etc & so on if necessary .
IF one contact breaker face blackend pitts or burns , the capacitor doesnt match the coil or V c V . Corectly Matched the points last well ,
and STAY SET .
Though lucas coils are a big joke unless theyre the sports coils . A BLUE and WHITE Spark of 1/2 inch is adequate . Less is NOT .
Lifting & dropping a point gets a free spark with the ignition on . If your not in some rowdy crowded cess pit , Turning the cam
with the ignition on and the crank set gets a AUDABLE SPARK , which you can fine tune to ' spot on ' STATIC .
precission in crank position gets precission in spark / degrees . If your slack its slack and the Hondas'll Get You .

Dont leave the papper in the points , or a bit of paper , or grit from sandpaer or elsewhere . If you KEEP IT CLEAN there wont be grit in there to wear it out either .
running it in the dark with the cover off after youve had the ciggarette should be far out too , and show if theres in leaks or shorts . one free strand on a Ign. Wire in there
is enough to upset the appkecart . So inspect the wires & if theyre F*ked , redo or redo the ends and resolder too .

To see if the coils are garbage , a free plug and a wire touched to earth should get a good spark . Matched by induced from points if that systens sound too . then she'll fly .
 
L.A.B. said:
MikeM said:
L.A.B. said:
Do you have a strobe?

Yes I do have a strobe.

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?
The gist of it is this. I had the engine rebuilt. Not by me but a professional rebuilder. The thing now runs great. I am looking ahead. When I first got it I tried to use the manual to set the points. I tried to lock the advance like the manual said and set the points. Mucked it all up. Strobe didnt look right etc. I know I didnt do it correctly. I just want to learn to do it correctly.
Is there a step by step to do it correctly? Is there a dwell setting or value?
Seems like it should not be difficult to do this. The damn things seem very touchy.
 
Set the points the same way you get to Carnegie Hall. If you follow this analogy you will be proficient in no time

And for what it is worth, you should realize that it is not a set and forget thing.
 
You do have to check the point gap and timing about once a year in my experience as the plastic heal on the points wears. Generally, I have found the bike gets harder to start the more out of adjustment they get. You should also use this opportunity to lube the aau at the same time. If the bike is running at all you should not have to set the static timing. Just mark the plate and case with a felt tip marker before you pull the plate off to lube the aau. Put it back on in the same position. Adjust the point gap and start the bike and set the timing like I described in my previous post with a strobe. I fooled around with points on my Bonneville, same Lucas 6c type, for ten years. I never set the static timing once even after taking the plate off every year and a couple of times taking the points off the plate. All you need to do is get it close enough to start and get the strobe on it right away.
 
The Timing ADVANCES as the points heal wears / gap closes .
Probably the reason for the 28 Deg. setting .

If you KEEP AN EYE on them , as in check the gap every 1 or 2 thousand miles , after you know theyre behaving themselves ,
youll seldom find theyre far out . After say three gap settings , youd recheck the timing.

If she gets crankey and lumpy to ride , youd suspect the points closed a dick & a trifle advanced .

Theres a awfull lot about on google on ignition ( 10 CA ) and carbs , IF YOU SEARCH .
 
Matt Spencer said:
The Timing ADVANCES as the points heal wears / gap closes .
Probably the reason for the 28 Deg. setting .
If you close up the points gap and adjust nothing else, the timing becomes more retarded. It doesn't become more advanced.
Let's just say your engine was at a position where the points were just opening, and open by 0.001".
Now close the points gap by 0.005". They will then not be open, and the engine will have to be rotated closer to TDC when they do open (more retarded).
 
turn the injun to the point where the paper frees / contact opens .

IF YOU OPEN the gap , itll happen LATER .

If you CLOSE the Gap , Its already happened . So is EARLYER - More Advanced .
ping pong clatter , so @ 31 BTDC ( 3/8 in. ) its important to know your points .
 
Matt Spencer said:
IF YOU OPEN the gap , itll happen LATER .

If you CLOSE the Gap , Its already happened . So is EARLYER - More Advanced .
ping pong clatter , so @ 31 BTDC ( 3/8 in. ) its important to know your points .

These notes are for setting the 4CA points however, adjusting the points gap on 6CA and 10CA should give the same end result.
Increasing the gap advances the ignition, and reducing it, retards.
Setting Commando points


http://classicmotorcycles.about.com/od/ ... ystems.htm
One of the shortcomings of the contact point ignition system is the tendency for the heel on the points to wear, which has the effect of retarding the ignition.

http://www.s262612653.websitehome.co.uk ... timing.htm
As the points wear, the timing tends to retard significantly
 
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The sparkplug gap also has similar but reversed timing effect, ie: more gap delays spark but very must. Same for point gap not changing timing much. Bbetter to set dwell gap as close to factory spec then twist plate on cam and points on plate to time. Does anyone know how to use a timing light to set points before initial starting?
 
Yea Matt I had to stop using 240 v 3 phase points contacting test light as power company complained about the jitters sent back up their grid. Once it is time to start and finally check with timing light its said to be better if its on its own battery power in case the bike battery volts drag down too much over test interval warming up or idle between fumbles. Lovely views of such ancient sparking gizmo, thanks got the flash back.

[video]https://www.youtube.com/watch?v=a67_m42d860[/video]
 
Matt Spencer said:
I must be catching the inatey L.A.B. :(

NORTON , so it says on the timing cover . So theres a chance it might be . :x

Setting Commando points
It looks like one set of points is now buggered, from being opened excessively enough to cause the spring to yield and lose tension.

Supposedly if you set the points to 0.015" at the scribed line on the cam, they will have have 0.015" gap all around the high part of the lobe (if the AAU isn't bent). Most are bent from being from being removed in a less than careful manner (they bend easily and are straightened easily). If it runs true, you'll have 160 degrees dwell at 0.015" gap, like Lucas intended. So the points will stay closed for 160 degrees of cam rotation, and be open for 200 degrees of cam rotation.

If you close the points gap, dwell angle will increase. The points will close earlier and open later, to give a longer closing time (in degrees). Gap changes will affect timing.
 
Lucas coils get fairly hot in use d/t the charging vs disharged intervals so dwell might matter most in that regard.
 
hobot said:
Lucas coils get fairly hot in use d/t the charging vs disharged intervals so dwell might matter most in that regard.
Those coils get a bit hotter with the average EI system, than they ever did with points.
A 12V coil has 3.2 ohms resistance, so with points at 14V, it has 4.375 amps for 160 degrees. It then has 200 degrees of cam rotation to cool off again. 44% duty cycle at 4.375 amps (average current 1.944 amps).

With 2 x 6V coils (typical EI), they each have 2.1 ohms resistance, so a total of 4.2 ohms. The duty cycle is about 80% (88% at idle and 78% at 5000 rpm for a Boyer). Average current at idle is 2.5 amps, but it does drop to less than 2 amps when you exceed 4000 rpm.
 
snipped If it runs true, you'll have 160 degrees dwell at 0.015" gap, like Lucas intended. So the points will stay closed for 160 degrees of cam rotation, and be open for 200 degrees of cam rotation.

If you close the points gap, dwell angle will increase. The points will close earlier and open later, to give a longer closing time (in degrees). Gap changes will affect timing.

What will the dwell be with a .016" gap?
 
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. -Hobot

If you can get it close enough to make it run with static timing, the strobe will tell you which way to go to get it spot on. It helps to have 2 people since the points are on the opposite side from the timing mark, but I recently did it alone on the Titanic's Boyer. First shot was too far advance; I shut down the engine, walked around the other side and adjusted. Fire up again and check and it was too retarded. Shut down, adjust again and on the third flop, the advance was spot on. A little fiddly working alone and a bit of lucky guesswork to get it just right by myself. One person setting points alone would have a half-day job. Another vote here for EI.

Set the gaps, put the alternator rotor on the mark and use the individual adjusters to break the points (cigarette paper method) at full advance and then rotate the engine and do the same with the other set. This is AFTER you get the plate set closely. If you put one point set's individual adjustment in the middle and use the rotation of the plate to break the points, you should be close.
 
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.-concours

It's been 40 years since I actually had to do it, but I thought both sets were individually adjustable on the plate. If not, my foggy memory stands corrected. When I pulled the points plate out of the Titanic, I didn't even look directly at it for fear of arousing sleeping gremlins.
 
One person setting points alone would have a half-day job.

Working alone it takes me no more than about ten minutes to set two sets of points with a strobe. No need to shut the engine off each time either (points or EI).

It's been 40 years since I actually had to do it, but I thought both sets were individually adjustable on the plate. If not, my foggy memory stands corrected. When I pulled the points plate out of the Titanic, I didn't even look directly at it for fear of arousing sleeping gremlins.

Yes, both the 6CA and 10CA ('73-on) points assemblies fitted to Commandos have adjustable backplates for each set of points.
 
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