ignition timing 0n 550 four k3

[bigmockuk]

I must be doing something wrong here,dont think so but must be.Allways had 2/3 silencers running cold or misfiring ( they run somtimes) and blaming 40yrs old boyer ignition module so,bought points back plate+new points/condensers and set left set of points to 14 thou when fully open,then set right points the same,turned back plate and using bulb/wires got it to light as 1/4 marks aligned.did same with 2/3 points back plate til marks aligned.bike reluctantly starts but no power and stutters,totally flat sound! and cuts out but would continue to tick over roughif restarted,real rough,no 3 misfiring badly.got freezing cold and tired so ended up moving back plate anti-clockwise fully and engine shot into life so moved no 2/3 back plate and amazing difference but tickover rough.only thing is,timing is well out but it runs with purpose? question is tho....why wont it run after static timing was spot on? static shows completely different from what the strobe says.any ideas as im getting exhausted with this cheers.p.s. i run pods with original pd46a jets and plugs/manifolds are badly sooted black but dry, thanks

[Johnwebley]

the fact 2-3 run iffy could be ignition,
they use same coil,points etc,

 check plug caps,is the resistor ok ?
 are you using resisitor plugs,a no no with resistor caps,

 a long shot,but when you assembled the ignition cam,did you assemble it 180 out ??


 I personally would put the Boyer back on and check coils,leads and caps

[deltarider]

The easiest check first. All CB500/550s are prone to misfires due to (intermittent) arcing between HTleads or caps to the head (= GND). This is best observed at idle in the dark.
Then I'd check the resistance of the plugcaps #2 and #3 and if their connection to the wires is still good. What plugs do you run, with or without "R"?

[K2-K6]

The points should start to open at the 1,4 F mark. So if you you have supply from battery through bulb and then through the wire to points, it should be on until it gets to the F mark at which point it should go out.

The points are switching the earth to coils,  all the time the points are closed it will be making the circuit live to store energy in the coil,  when the earth is removed ( by points opening) it fires the HT voltage to the plugs.

Looks abit backwards at initial viewing,  but it works that way.

[hairygit]

If you're running stock jets with PD carbs and pods, it will be running very weak, the PD carbs run lean anyway, and with pods, well! More likely to be a coil on it's way out, or a dirty/loose connection in the wiring to the coils. Check and clean ALL joins in the wiring from the points to the coils, especially the connectors that join the points wires to the main loom, near the back brake light switch, they get incredibly dirty/corroded there. Did you clean the faces of the points to remove any protective oil/grease put on at manufacture before fitting? What pipes are you running? Almost certain this will be an electrical issue though.

[bigmockuk]

wow thanks for the quick relies guys! right first off,i fitted new ngk cr8es plugs,got new 5ohm caps and cheap 5 ohm coils from ebay,2/3 still acted the same so disconected wires at boyer module and ran original wires up to the coils and fitted a plate with new points/condensers from ebay.i thought if i went back to conventional ignition and it worked this would prove the boyer faulty."john" you mention the ignition cam being 180 out? are you refering to the lobed cam on the advance unit? that could be poss i guess? "deltarider the lugs are "r" i wouldnt have thought that would really have any effect? K2-K6 you say light should be on  mine is off then go off? mine is off and comes on when points open,strange."hairygit i know what you mean by running weak but mine is exact opposite tottallysooted up like pure black but im thinking maybe a malfunction in ignition could cause this?.im running 4-4 original pipes and have cleaned faces of the points.if i connect strobe to no1 the light dont flash but will if connected to no 4.it will flash if connected to no2 but not no3 this cant be right surely it should flas with all 4?

[bigmockuk]

just a thought,is it possible the auto advance unit i bought is from another model? maybe cb500 or that

[jon stead]

Has your bike ever run correctly with the Boyer ignition on it?

I chased a fault for a long time, caused by the Boyer 6v micro coils having been wired in parallel instead of series. This was causing poor starting, erratic tick over and poor performance. Your Boyer system might’ve used the original 12v coils so it might not be this.

Also, my Boyer, didn’t use the advance/ retard weights on the a/r unit, just relied on going to full advance, electronically at 4,500 rpm. Have you refitted the weights to the a/r unit now you’ve gone back to conventional points?

I agree with the others that if the fault is on a pair of cylinders, it’s likely to be electrical. Good luck.

[K2-K6]

If you describe how you've connected the light we can see what is supposed to be happening with it.

Which terminals do you connect to? And do you disconnect the lead to coils to setup?

They'll run with whichever advance unit,  you can sort it out if wrong after getting it firing reliably.

If the cam is assembled 180 degrees out it'll not usually run until you connect the points to the wrong coil (so reversing the error) or swing the points plate so far it comes in range to make it go.

Another post on here recently showing how to check the above,  I'll try and find it.

[jon stead]

just a thought,is it possible the auto advance unit i bought is from another model? maybe cb500 or that

If you had the same poor running fault with the Boyer as you do now, then it’s possible it’s not the points.

[bigmockuk]

"Jon" yes i had the bike running real good then had battery prob so jumped the bike off the car (switched off) and thought i must have fried something basically so bought new coils and same intermittent fault was there so thought it could be boyer so trying to go with points set up to see if it runs or how it runs.the boyer does not have weights either just centre cam and an annoying plate with 180 magnets that are not aligned to anything so have to guess thru trial/error as to when their lined up."K2-K6" i earthed one lead to engine casing and other to blue or yellow wire on the points with ignition on.there was no real difference from new coils to old coils so might be better with original coils which were not as flimsy.with boyer and using strobe light its impossible to line up the "F" mark it line up with full advance marks,should this be right

[K2-K6]

Apologies,  I do it with coil leads disconnected,  so you should get light on to fire when connected in your way.

If you time it as you are familiar with,  then swap the two coil leads so that they go to the wrong colours,  then see if it runs. This will tell you if the points cam is the wrong way round as it'll put two errors opposite to each other and cancel out. If successful you can then realign both to make it std.

[bigmockuk]

Cheers K2-K6 im on my way up to the garage the now with renewed hope,i`ll strip wires and check for breaks/corosion as hairygit was saying,realign timing,if no joy i`ll swap wires on route to the coil and see if it fires up.i also wanna remove no4 plug and use a long screwdriver to determine when piston is at tdc and check timing plate to see if they match up as they should do.i`ll check the color of the spark at each plug too.maybe even worth trying old coils too.i`ll report back later with my findings and once again thanks for all your ongoing help

[Seabeowner]

if i connect strobe to no1 the light dont flash but will if connected to no 4.it will flash if connected to no2 but not no3 this cant be right surely it should flas with all 4?

If your strobe has an inductive try flipping the pick it over as some are sensitive to polarity..

[bigmockuk]

Hi just an update,i checked the wiring and all seems ok,i checked the valve clearances and found 3 needing adjusted,no3 inlet had no clearance.instead of using a light for the timing i switched ignition on and slowly cranked until spark at the plug on no4 with plug against the head,both 1/4 2/3 were advanced by around 5 degree and no more room for adjustment so i took a dremmel buff and enlarged the the 3 slots in back plate.bike starts and runs very well except no3 which tends to now backfire as if reigniting unburned fuel in the exhaust but its ticking over and running.still to balance carbs tho so that might help and only set mixture screws at 1.5 turns out so im getting somewhere at last with the points set up! so cheers again for all your help/advice guys.i have one other niggling problem that i`ll put in a new post and see if anyone has any clues