new valve job - but now won't start - Help!

75 Commando- Mark III
Got my head back from a valve job at Rabers. Put it on carefully, with new head gasket, pushrods seated properly, adjusted the valve clearances per spec, then torqued everything down just right.

But.... while putting the head back on i had pushed the wiring harness out of the way at the coils. Realized that i pulled a couple of connectors off the coils in the process, so put them back on. (Have a Boyer - has been installed and running for years).

Tried to start the bike, but got nowhere. Looked carefully at my reattached connectors on the coils, realized i had mis-placed a couple. Traced everything and put it all exactly the way its supposed to be (per Boyer installation instructions - and looks like the way it was before too).

Tried to start it again - it would catch for a second, then die. Got this repeatedly, now it won't even turn over the starter motor. Battery is fully charged.

No spark at plugs now either.

Shit - did i fry something in the electrical system with my misplaced wiring on the coils? What is most likely candidate? Suggestions for testing? (Electrics and i are not very compatible).

All dressed up in Encinitas - help!
Keith Kelly

I don't think that you can have damaged the Boyer due to wrong coil connections.

First things first, have you shorted something and blown the fuse ?

Have you tried the kill switch ? If you're electric starting, it will run all the time that the starter button is depressed but then stop.

Even if there is no spark from the Boyer, the starter should still spin the motor over. Have you still got warning lights ?

Have you recharged the battery ? I would try this and then run a 'lot wire' direct to the Boyer live feed to make sure there aren't any problems on the way. The Mk111 has a mass of multi-connectors under the tank. Not a bad idea to take them all apart, spray with switch-cleaner and replace - I do this annually as a precaution.

Watch out for the problem of low volts with the Boyer on the Mk111 once you get it running because a backfire starting will not help the sprag at all.

79x100 said:

Have you tried the kill switch ? If you're electric starting, it will run all the time that the starter button is depressed but then stop.

Click to expand...

That shouldn't really happen with a Boyer ignition, (although not totally impossible?) as the box is powered by the ignition circuit (White wire), so if the kill switch was off and therefore interrupting the ignition circuit then the box would not trigger, as there would be no power supply to it.

The White/Purple ballast resistor bypass wire from the solenoid would originally have connected directly to the coils, so should have been disconnected when they were rewired for the Boyer? And even if the bypass wire was sending 12 Volts to the coils during cranking it would not trigger the Boyer.

The only conceivable way it could happen would be if the White/Purple bypass wire had somehow been connected directly to the ignition/Boyer White circuit wire, and the starter then operated with the kill switch in the off position (or a break in the kill sw. circuit) it could then power the Boyer box as the starter operated and stop the moment the switch was released, the same as the points system?

I would suggest temporarily connecting the Boyer box directly to the battery and then checking for sparks again (with a fully charged battery).

L.A.B. said:

79x100 said:

Have you tried the kill switch ? If you're electric starting, it will run all the time that the starter button is depressed but then stop.

Click to expand...

That shouldn't really happen with a Boyer ignition, (although not totally impossible?) as the box is powered by the ignition circuit (White wire), so if the kill switch was off and therefore interrupting the ignition circuit then the box would not trigger, as there would be no power supply to it.

Click to expand...

Oh erm whoops !


To be honest I threw away my kill switch when I junked the starter but I really thought that it could still pull this trick even after I'd fitted the Boyer. Must be the old memory playing up.

All the symptoms suggest that I do indeed suffer from C.R.S.


(Can't remember shit !) with apologies to the original author !

now it's serious!

Appreciate your words of wisdom and suggestions.

The battery is fully charged. The kill switch is in the "on" position. There's juice to lights and horn.

Newest developments:

after a couple more tries, the electric starter now just makes a horrible low whirring/growling sound and doesn't turn the engine over. Maybe it finally gave up the ghost. Still no spark to the plugs with the kick start.

I didn't have a piece of wire handy to try the "direct from battery to white wire on Boyer black box" suggestion, but was going to roundnd one up.

On my last push of the starter button a few minutes ago, i got a loud pop (explosion) - sounds like right behind the battery. That's it for my attempts to get this going. Doing more harm than good.

Now i really did it - shit!

Anxious in Encinitas,
Keith Kelly

If there was a Norton shop around, I'd put the bike on the back of a truck first thing tomorrow morning, but no such luxury. Maybe I'll try GP Cycles or Rocket Motorcycles in San Diego tomorrow. They both have vintage brit bikes sitting around on the floor. Maybe they could actually work on one.

starter solenoid is behind the battery. im sure that baby's toast. i would pull a wire off of it since you might have shorted it.

Don't forget the old "Electric assister" period magazine quotes that eBay sellers love using to justify why theirs don't work.

I would remove the starter from the equation by using the kickstart. In fact, I would never try to get a reluctant Come-an-go to start using the electric method.

If the battery is charged and the Boyer is connected you should easily get a spark at the plugs with them resting on the head by kicking it over, as should also occur each time you turn the ignition on and off.

The pop was probably just unburnt fuel popping back through the carb. If the volts have dropped (as they soon will using the starter) then the timing will be all over the place.

Do you know that your battery is a good one ? It wouldn't be the first one to be defective.

start by ripping allyour connectors off . make new (even temp ones)from black box to coils and pick ups then connect white feed straight to battery . take plugs out but hang on ht leads with plugs on cyl head as to make earth Do not forget to connect two coils together(+ to -)
kick over and you must see sparks .If not try other black box(they do go bang you know)replace your plugs and kick .if it tries to break your leg swap ht leads over

it's a miracle!

My bike started - but it's kind of a twilight zone thing.

Went to the auto parts place and got a piece of wire with alligator clips on both ends.

Before testing anything, I tried a push of the starter button. The starter turned over and so did the engine.

After the noise it make last night i was sure it was fried. Guess it just needed some quiet time to do starter yoga or whatever those things do when they are alone.

I pulled plugs out and checked for spark with the starter button. Eureka - spark on both plugs. This is good but i don't get it.

Put a simple bulb-type tester on the white/blue wire (power) I had connected to the white lead on the Boyer black box. Nothing. Ignition on - nothing. Push power button - bulb lights up.

That explains why the engine was firing while yesterday while i was holding down the starter button, then cutting out as soon as i let go the starter button. Duh!

Next - put my test wire from the hot post of the battery to the white wire on the Boyer black box. Voila - the fucker starts up on half a kick (as it should). Damn, this is weird.

So i just have to find which wire to connect the Boyer white wire to - one of those rats nest of connectors - one that is only hot with the ignition on. I'll go back out after dinner and find the right wire. All should be ok after.

Though i am still wondering what the hell that explosion was last night. I had my hand on the frame near the battery (seat off) and it scared the hell out of me. Should i be worried - or just ride?

Keith

update on misplaced coil cluster wires

Turns out the instruction sheet that come with the Boyer for the COmmando Mark iii comes with a small print footnote.

All references to the power wire from ignition refers to a white/blue wire. But the note elsewhere in the instruction sheet says that that some models have a different color wire, and to test to find which it is hot with ignition on.

I had been connecting to what i thought was a white/blue wire (on close inspection, it turns out it was white/faded black). This wire only has power when the starter button is pushed.

There's a white/yellow wire though, and is is hot with the ignition on.

Connected to that one, kicked it over, and presto. Everything works the way it is supposed to.

Mystery solved

Thanks for all the suggestions.

keith

Re: update on misplaced coil cluster wires

pkeithkelly said:

All references to the power wire from ignition refers to a white/blue wire. But the note elsewhere in the instruction sheet says that that some models have a different color wire, and to test to find which it is hot with ignition on.

I had been connecting to what i thought was a white/blue wire (on close inspection, it turns out it was white/faded black). This wire only has power when the starter button is pushed.

There's a white/yellow wire though, and is is hot with the ignition on.

Click to expand...

Yes, the Mk3 ignition wire is normally White/Yellow (after the kill sw.). The "white/faded black" you mention is very likely to be the White/Purple I was talking about if it was connected to the solenoid, so can be left disconnected at both ends as it has no function if a Boyer (or other electronic ignition) is fitted.