Can’t Get Timing Correct

Thank you all for your counsel, especially L.A.B who helped me understand the various functions of the various slopes on the timing cam. Bike started and is running on both cylinders. I have yet to strobe time and optimize carb settings. I conclude that my initial problem was likely TriSpark failure and upon installation of points was improperly setting the points cam position
 
You know where the spark needs to occur - get your head straight and get it right. If there is an auto advance, lock it on full advance - set the timing and then remove the lock. It does not matter if the auto advance is worn to buggery or the chains or cam gears are worn - all you need to do is make sure all the slack is taken up, so the spark happens at the right time when the motor is revving above idle.
 
So, I've been pretty critical here, so let me say this:

When I first got my commando, I had a very similar situation. I saw the previous owner ride my bike, so I knew that it ran. Once I got it, I just couldn't keep it running. I could get the occasional start, but it wouldn't stay idling and it would die after a few throttle blips. I even got so desperate as to tie a rope around the headstock and have my friend pull me around with his car to try to jump start the bike.... I've never heard of anyone else doing such a stupid, dangerous thing, but I was young and stupid at the time. After finally having a near crash while doing that, I gave that up for good.

On the day that I finally found the problem and fixed it, I was working on the bike in the driveway, kicking away and getting the same intermittent result. The bike would start about 1 kick in 5, rev up in response to the throttle blip, but then die. Eventually after 2 days of kicking, testing, troubleshooting, and going in circles, my friend who was going into town to buy lunch, saw me struggling and said, "What plugs are those? I'll stop at the parts store and get you new plugs". I told him that I tested these plugs by spring clamping them to the head and kicking the bike over and they both sparked fine. He still insisted on getting me new plugs and I relented to his offer.

We ate lunch, then I switched out for the new plugs he got me and the bike started on the 2nd or 3rd kick. It started and stayed running. I was happy, but also confused because I actually tested the old plugs and they sparked fine when spring clamped to the engine fins, so I assume that meant they tested as good. Later, our mechanic friend explained that sometimes the plug insulator is cracked up inside the plug where you can't see it so it tests ok outside the engine, but under compression it sparks up inside, where the insulator is broken, so it doesn't light the charge inside the cylinder..... It tests good but is not good.

The lesson of this story is that although "test, don't guess" is the rule. things like a new set of plugs are exceptions because they are cheap and can test good and still be intermittently bad... So, if you haven't put new plugs in because the others tested good,.... it wouldn't hurt to have a second set of new plugs,... just in case.

I'm glad you are making progress and have the bike running now. If you suspected the boyer caused the original problem, and then suspected the Tri-spark as also being bad, that's not impossible, but seems like that it would be a longshot for both to be bad. However, since they are both electronic ignitions, they may both be more sensitive to voltage drop. Maybe test for your battery health and that your rotor/stator set up is charging properly..... low voltage is an issue with electronic ignitions... good luck...keep going
 
Ralph Dill said:
Long story. Much work over the last year. Memory now confused over what happened when. Bought bike 8 years ago and it ran well for 7 of those years. About a year ago it started to run poorly and became difficult to start. PO had installed a Boyer ignition which after much work I suspected it was failing, so after having had so much success with the installation of a TriSpark ignition in my Triumph Trident, I installed one in the Commando. It ran well for a time, but then began exhibiting the same aforementioned faults. I ran the TriSpark diagnostics which indicated it was OK, so I then focused on carburation and installed a new set of Amal Premiers which did not solve problem, so I am back to ignition. I also have a Truimph Bonneville that I bought new in 1974 that always runs well and still has points for ignition, so I thought that since I can not diagnose electronic faults and points are mechanical, I would convert to points so eliminate ignition as the source of my issues, but I have struggled in getting the set properly. Various attempts have resulted in total inability to start, or a violent explosions seemingly coming from the left exhaust. That is where I am now. Have yet to apply any of the learnings from the forum. Maybe tomorrow or Monday. Thank you for your interest. And yes, I am now getting spark at the plugs.
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I had trouble with the Trispark, miss firing at 3500rpm and up. After checking the wiring I found my way to the key switch and reconditioned it as per advice on this forum. No further trouble, might be worth a look.
 
The Trispark is less sensitive to low voltage than an older Boyer - can't say about the current Boyers. Of course, points/AAU are, for practical purposes, totally insensitive to low voltage and will provide some sort of spark at the correct time at voltages where an EI won't even wake up.
 
Ian James said:
I had trouble with the Trispark, miss firing at 3500rpm and up. After checking the wiring I found my way to the key switch and reconditioned it as per advice on this forum. No further trouble, might be worth a look.
Click to expand...
Ian
Can you post what that thread is please? I don't have a problem but would like to know "just in case".
Cheers
 
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Fast Eddie said:
That’s fine.

You need to get with the programme.

Blindly flailing around in the dark seems to be THE approach to problem solving these day IMO… at ALL levels…
Click to expand...
It's called a "parts cannon".
 
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The infernal AUTO ADVANCE mechanism is a SERVICE ITEM .

I was lucky , given a BSA unit with the opposite parts to mine worn . Both were clapped out . But 50 % of each was not . Lucky It Made a 100 % one .
with the BSA 24 degrees advance , rather than the Nortons 16 ??

To repeat the lecture for the 5.000 th time ! Strip , CLEAN , inspect . The A Adv mech . meticulously clear . AND in the bores .
Check fredom of operation. dry . no burrs , sticking , tight spots , SLACKNESS , rattle circufrentially . ( Cam dont sift radially on shaft ) .
Flog some new springs from the neigbours Morris 1100 . ( just about ALL Lucas A adv springs fit ! )
I was advised to fit stiffer ones . It made it less prone to light up , getting underway . But less touchy below 3000 odd . depends wotyer like .

Maybe Chain Lube , Chainsaw Lube , Moreys , treacle or suchlike . Coat FULL surfaces - wipe damp . KEEP THE DUST OUT .

OF COURSE youve POLISHED the Points Cam , to a mirror finish !

Lube that fully & wipe . Lube orrible white nylon points heel across . Grease . Toothpick . Swing Over a few points cam rotations .
Tootpick to remove small bead of grease at cam heel . THAT'LL see they DONT pick up , melt , close the points , advance the ignition,
melt the pistons , throw the rods , put the debri thru the bearings , and a few other things .

Creep Out at 2 in the Morning , and Start it up , Points Cover OFF .If theres showeres of sparks everwhere in the wireing , and jumping at the points , somethings not right .
If the Lights ON , you miss all this ! .

It should have a equal sharp blue / white ' snap ' with no tracking & dithering

Look at the date & voltage stamped on the coils , then go and play on the road .
a GOOD coil jumps 1/2 at the lead & the SPARK is Blue & White .

sub par 3/8 min . red yellow ditto .

12 V & megawatt coils cant hurt , but condensors must match . Dead Balanced neither C.B. contact erodes . The one that does tells you if condensors to much or to little .
So , if one erodes , SOMETHINGS OFF . like shitty wireing connections ! You wanna blueprint the brass terminal connections so as theyre all firm . no wiggle .

Give ALL wire connectors a loving douse of C.R.C. to keep moisture & oxidation OUT . Really cunning lazy honda types just throw a can of contact cleaner at it , and have a beer . Instead .
 
Matt Spencer said:
The infernal AUTO ADVANCE mechanism is a SERVICE ITEM .

I was lucky , given a BSA unit with the opposite parts to mine worn . Both were clapped out . But 50 % of each was not . Lucky It Made a 100 % one .
with the BSA 24 degrees advance , rather than the Nortons 16 ??

To repeat the lecture for the 5.000 th time ! Strip , CLEAN , inspect . The A Adv mech . meticulously clear . AND in the bores .
Check fredom of operation. dry . no burrs , sticking , tight spots , SLACKNESS , rattle circufrentially . ( Cam dont sift radially on shaft ) .
Flog some new springs from the neigbours Morris 1100 . ( just about ALL Lucas A adv springs fit ! )
I was advised to fit stiffer ones . It made it less prone to light up , getting underway . But less touchy below 3000 odd . depends wotyer like .

Maybe Chain Lube , Chainsaw Lube , Moreys , treacle or suchlike . Coat FULL surfaces - wipe damp . KEEP THE DUST OUT .

OF COURSE youve POLISHED the Points Cam , to a mirror finish !

Lube that fully & wipe . Lube orrible white nylon points heel across . Grease . Toothpick . Swing Over a few points cam rotations .
Tootpick to remove small bead of grease at cam heel . THAT'LL see they DONT pick up , melt , close the points , advance the ignition,
melt the pistons , throw the rods , put the debri thru the bearings , and a few other things .

Creep Out at 2 in the Morning , and Start it up , Points Cover OFF .If theres showeres of sparks everwhere in the wireing , and jumping at the points , somethings not right .
If the Lights ON , you miss all this ! .

It should have a equal sharp blue / white ' snap ' with no tracking & dithering

Look at the date & voltage stamped on the coils , then go and play on the road .
a GOOD coil jumps 1/2 at the lead & the SPARK is Blue & White .

sub par 3/8 min . red yellow ditto .

12 V & megawatt coils cant hurt , but condensors must match . Dead Balanced neither C.B. contact erodes . The one that does tells you if condensors to much or to little .
So , if one erodes , SOMETHINGS OFF . like shitty wireing connections ! You wanna blueprint the brass terminal connections so as theyre all firm . no wiggle .

Give ALL wire connectors a loving douse of C.R.C. to keep moisture & oxidation OUT . Really cunning lazy honda types just throw a can of contact cleaner at it , and have a beer . Instead .
Click to expand...
And, put the Tri-Spark back and find the real problem! One side failing is not a Tri-Spark (or Boyer or Pazon or any of the wasted spark systems) thing. There can be a bad spark plug wire or coil secondary and even a coil primary is possible but since both coils are required to have a circuit, one side working tells you clearly that the EI itself working! And, getting a Tri-Spark to work is way easier than getting points, condensers, ballast resistors, auto advance, and so on working.
 
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