wiring problem continues

OK, I need some advice from a clear head. The wiring problem I've developed on my 73 has got me completely stumped. Last fall I rode the bike approximately 3000 flawless miles and parked it in the garage for the winter. The bike wasn't touched all winter. The boyer has had the plate drilled and screws replacing the solder connections. The black box has been swapped to ensure there isn't a problem there. The wiring was gone through from front to back of bike to make sure there isn't a short somewhere and I can't think of a wire I've missed. The ignition has a bypass from the ignition switch to the boyer direct omitting the harness for the most part. There is a brand new good fully charged battery installed, old crusty ignition switch was replaced. The symtoms are the bike sparks intermittently. Will start first kick and sometimes die immediately and not restart again for an indefinate time, no rhyme or reason to it. The bike will fire and run for say 20 seconds or at one time rode for 2 miles and like the snap of a finger loose spark and die. With the plugs out if I turn the ignition switch on and off the boyer sparks , but not always, when the bike is kicked there is spark sometimes, then it is gone. Can anyone tell me what has been missed or if I've done something wrong. I am at a loss and have had a good friend that I consider very good as a troubleshooter and mechanic look at it and he to is at a loss. As he put it last night "In thirty some years of wrenching I've never had a bike I couldn't unf**k, but this thing has got me"

Obviously I'm grasping at staws, but is the earth definately 100% on the engine and frame and all of the time?

I'd substitute the backplate as well. I know that you have had a look at the wires to your backplate, but last year I re-soldered the wires on my backplate, and then epoxy-resined them to the front of the back plate. I thought it would be more secure than before, but some how despite looking perfect, there was a fault. I couldn't get it to start. It would fire and pop, and "nearly" run etc, etc and I was convinced it was the carbs, but it was something on the backplate, instantly cured when I fitted a new one! Anyway, if you get my point, substitute this and the feed wires to it, and if the problem remains, that should be another item definately excluded.

I'd put money on it being a bad connection/broken wire. You didn't mention the coil. Have you checked all the wiring to it? I once spent ages chasing a similar problem and one of the spade connectors to the coil had been put on with the spades not engaged, by which I mean the plastic insulator around the spade was holding it in place.
Check all the things that you think don't need checking.

When I changed the black box I also change the wiring to the coils. I guess I to am grasping here and thought perhaps I am missing the obvious being so close to the problem. My guess was/is a broken wire or the pick up plate, but I cannot find it nor my long time friend. Things don't break by sitting, so corrosion is the only answer I can come up with given the fact it ran great when put up for the winter. I just wanted to make sure I am not missing something obvious here. Next thing I can think of is to start replacing components one by one including the wiring and all ignition parts..........I don't like the expense of that proposition as I'm in way to deep on this machine as it is. I can say I have never had a bike as problematic as this one

Thanks,

Tim

If, as you say the appearance of a spark at the plugs is intermittent, then it almost has to be a wiring problem. Electrical boffins always say that there is no such thing as an electrical fault, it is always a mechanical failure of components or materials.

The Boyer is supremely sensitive to poor connections. They don't have to be visibly corroded, just "dry".

I replaced the wiring harness on my Mk111 several years ago, just to keep it standard really, I should have hard wired it. I had intermittent misfires and loss of sparks, sometimes with loss of warning lights and sometimes not. After hours of checking with the meter, I was reduced to wandering round the house saying "I can't do it anymore, the bu**er's beaten me !"

I eventually found with the tank off and a plug on the head that I could produce a spark at the plug by blowing on the harness or waving my hand near it ! The problem turned out to be that the new harness had been tinned and then crimped and had come ever so slightly loose in the crimp. Pushing on the wire made a connection and so did pulling but somewhere in the middle it didn't. The Mk111 has a feed to the switch and one to the kill switch connections and both had the same problem. Sometimes one failed, sometimes the other.

I don't suppose that this is your problem but it highlights how obscure these silly faults can be and how dificult to find if they won't replicate under test.

Keep trying, you'll find it eventually !

I noticed today getting ready to go back through everything there is a seal going in the timing or pick up plate cavity. Would oil getting thrown around in there under the pick up plate cause a loss of spark? I may be grasping here, but I won't learn unless I ask.

I don't see that oil contamination would cause the problem.

But is there any oil leaking into the timing cavity?

britbike220 said:

I noticed today getting ready to go back through everything there is a seal going in the timing or pick up plate cavity. Would oil getting thrown around in there under the pick up plate cause a loss of spark? I may be grasping here, but I won't learn unless I ask.

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In the short term, my experience is that it wouldn't. Following accident damage to my timing cover, I bought a new replacement which turned out to have a blow hole into the points cavity. Before I discovered this, I replaced 3 or 4 seals and even found a source of the original red seals.

In desperation and because I hate oily bikes, I siliconed the cover on and ran a small pipe from the breather hole to a catch bottle. The thing was swimming in 50 weight and functioned perfectly.

In the long term, I think that oil could affect insulation etc.

Your symptoms sound much more typical of a wiring problem somewhere else but you'll probably only get to the bottom of it by substitution.

Despite it being a good basically reliable and inexpensive piece of kit, the Boyer's susceptibility to these problems will probably mean that I buy a Pazon the next time mine develops a case of the blind staggers rather than try to trace and rectify the problem.

Is your kill switch still connected, if so try bypassing it and see if that solves your problem. Had a similar situation on my '74, cleaned up the contacts on the kill switch and the problem went away, finally I eliminated the kill switch all together.

Just to add even more possibilities - When I took the Boyer disk out I noticed that solder on the back of the pick up coils was far enough out to contact the rim of the cavity in the casting. Hadn't noticed this causing a problem, but I put thin insulation behind anyway.

Also I put a relay in the kill switch circuit. Connected the ignition circuit to the normally closed contacts & fortunately there was a spare push to make contact in the handelbar switch cluster. This energises the relay to kill the ignition. Good theory :shock: - hope it works in practice once I get back on the road - this weekend with luck!

F_Magna said:

When I took the Boyer disk out I noticed that solder on the back of the pick up coils was far enough out to contact the rim of the cavity in the casting. Hadn't noticed this causing a problem, but I put thin insulation behind anyway.

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The two outermost solder points at each coil that I think you are referring to on the back of the pickup plate that can touch the casting are the anchors for the pickup coil retaining strap, and do not form any part of the pickup electrical circuit, so there shouldn't be any problem, just ensure that the blobs of solder do not stop the pickup plate from seating properly in the housing.

I had filed those solder points down when I replaced the connections with the screw type connections. If I have bypassed the main harness with a wire direct from the igition switch to the boyer box. Where could the possiblities be that there is a bad connection? Are there other contacts that are in the circuit? I did pypass the kill switch last fall. Is there anything in the left side handlebar switching that could cause a problem. Short of starting with a new harness, I am at a loss for ideas. One other thing how is the pazon unit compared to the boyer? I am not very happy with the boyer unit performance and wouls switch in a minute if there was something less prone to problems.

Thanks again

79x100 said:

"I can't do it anymore, the bu**er's beaten me

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That's how I feel about mine right now. :evil:

I ended up having one of the ignition wires (black/yellow) from the boyer pick up plate that was broken in two about four inches up the casing. Looked as though it had corroded, how, I'll never know. The darn thing was making intermittent contact causing my problems. Bike is back to running the way it was last fall, sweet and smooth until the next problem.

britbike220 said:

One other thing how is the pazon unit compared to the boyer? I am not very happy with the boyer unit performance and wouls switch in a minute if there was something less prone to problems.

Click to expand...

Just what I'm checking into britbike-two-hundred-and-twenty. It's all a bit of a conundrum.

I consider this list (i.e. accessnorton.com) numero uno for Commando owners, so don't take the following link as a ringing endorsement from me one way or another, as I know little or nothing about it. (I also understand if it's deleted by the moderator out of hand). Just happened about it when I "Googled" the Pazon units.

http://tinyurl.com/295pur

Pay attention to the second half or so of the discussion.... also, the very last. The Pazon representative clarifies a few things about the whole discussion.

Finally, please note that I just discovered today that Pazon - yeah, the whole company - is in the process of moving to New Zealand, so pretty much everything you might want to buy from them is back-ordered for a time. I have a theory on the move: they read ntst8's post of their New Zealand Norton retreat, in which he/she posted a most lovely pic of several Norton's surrounded by the gorgeous New Zealand countryside.

Cheers--

w/

wiring problems

Had a similar problem, and the mechanics I gave the bike to couldn't figure it out either, so was in the process of ordering a new RITA ignition when we found that the timing rotor ( the old points cover) had filled with water! The drain hole was blocked with polish etc, and I had cleaned the beast with degreasant and some soapy water. Hence the lumpy, mis-firing as the small amount of water splashed about in there.
You never Know sometimes!
Just fitted an amal mk 2 and single manifold, and going to attack the wring tomorrow- argh
Also noticed that if any 'modern' bike riders read this website they would run a mile before buying a Norton as there are so many 'fixs' and remedies to learn and know. Part of the charm I try and explain to the missus! :?