Another week, another problem fixed

Not open for further replies.
Apr 15, 2004
Country flag
So, I installed my new points and new condensers and new points leads then laboriously retimed the engine, confident my Norton 375 would once again be a Norton 750. Imagine how I felt when the f***ing thing wouldn't start! It was the same old story - it would fire up (on both cylinders again), run for a few seconds, then die. I suppressed the urge to push it over a cliff and quit for the night.

Today I found another problem. The fuse holder is not original, it's a replacement that was spliced into the harness with a soldered connection. It must be one of those Boyer fuseholders I've been hearing about :) because the wire right at the far side of the splice was mostly-broken. It only took a slight tug to finish it off. I made a temp fix by trimming the wires and resoldering them. That got the bike going! Was hard to start but once the plugs cleaned up it ran great :D

Now for the acid test: will it start again after sitting for a few days? It's track record for that isn't good but the wire has been degrading for some time. Tomorrow I'm off to the hardware store for some crimp-on connectors and a piece of wire for a more permanent fix.

The thing that puzzles me is I thought the bike was supposed to be capable of starting and running without the battery, using the big blue capacitor. Does that mean my Blue Thing On A Spring is bad too? The battery seems to be well charged so it appears the charging system is ok.


Those Boyer fuses are the worst!

You may want to check your alternator output. A rudimentary method of doing this is to simply attach a voltmeter across the battery with the bike running. And at 2,000 or so RPM, your meter should indicate some 14 volts.

If your alternator checks out ok then your Big Blue Thing hanging from a spring could be faulty. Or some of the wiring in its circuit could have Boyer's disease.

You're making progress; keep after it!


Hey Debbie,

You have not been alone with your dramas, we have all been through it once or twice. Keep at it, you are doing good. Pretty soon you will know your Naughty Norton top to bottom also.

I have been struggling with an electrical problem myself, even took it to the "professional" electrician. He checked it & checked it but no can find problem.

So I brought a new harness as all the other components were ok.

Gues what ??? It was the ***ing Lucas switch I purchased new less than 8 months ago !!!!!!!

It was working intermittently & the problem was inside the switch housing.

So, I think, I have finally got it...woohoo.

I go for a good ride up to a favourite haunt called Mt Mee, 60 kms away approx.
Having a real good time beating new Triumph, Bmw & FJ1200 back down the mountain, then.....

Go to overtake cars on the long straight just past Dayboro & BANG........throttle cable breaks at twist grip.

Such are the joys of owning Nortons :D

If u r wondering, yes, I do carry spare cables.

They say that if an engine has Compreesion,Spark & Fuel it should go..
Unless its' a McCulloch Chainsaw. (Or a Norton ?? )
Hi Debby
I recently went through a 'bout of troubleshooting that ended up being a simple blown main fuse. I had originally assumed the issue was fuel related since I had spark when the plugs were grounded to the head. After eliminating the fuel issue I went back to spark and noticed my spark was weak and intermittant. I also noticed I couldn't generate a spark from manually operating the points with a screw driver. I eventually found the obvious - a burnt fuse.
I was able to start my bike with many many kicks with out the battery inline due to the capacitor. Its hard, hit or miss and if it doesn't start the capacitor eventually loses what little juice it had in storage so the spark got weaker. So, my understaning is that these capacitors work but I wouldn't want to rely on one for everyday use. With the battery in line I get a much fatter brigher blue spark that starts the bike everytime. The moral is I believe it to make sense that capacitors lose their charge and need a source to rejuvinate or eventually it won't start without the battery.
There is a simple trouble shooting procedure for the capacitor I've seen listed in manuals, but I don't recall it since I never performed it.
Theres always something - Isn't this stuff the character referred to as one of the charms of brit bike ownership!
I was curious to see if mine would start with just the capacitor so I warmed it up then removed the fuse and tried to restart. Started right up and seemed to run fine. So if my fuseholder repair breaks I know I won't get stranded somewhere - the capacitor can get me home. I think relying on it for cold starting might be expecting too much though.


You have more or less just proved that the capacitor and alternator are functioning properly.

But there is a piece of the puzzle missing - why did the bike not start?

At the beginning of this post it sounded as if the fuse holder was at fault because once repaired, the bike started right up. This called into question the integrity of the capacitor. Now that we know the capacitor is OK, what was the culprit for the bike not starting?


Why was it not starting? Don't know. My theory is the capacitor doesn't store enough charge to get the bike going cold but is up to the task of starting a warm engine. Actually this morning, after sitting four days it started right up then died. But I was able to restart and keep it going until it warmed up. Then it was fine. I set the timing with a timing light and spent some time adjusting the idle. I have to say the bike is running pretty darn good now. But will it run next weekend? Or will the gremlins strike again? Stay tuned...

Potential answer to Jason query about the bike not starting -
The bike probably wouldn't start when it was cold and the fuse line was damaged because its simply hard to start with only the capacitor when the bike is cold. After attempting for a while it may have discharged the capacitor enough that the spark was too weak.
It probably started fine when warm and the battery was disconnected because the capacitor was fully charged due to recent running to warm the bike and the bike was easier to start anyway since it was already warm.
Good explanation there dynodave.

Back in the early 70s, we installed capacitors on choppers to eliminate the unsightly battery and associated wiring. These capacitor systems would start a cold engine with no problem; the headlight would flicker at idle though.

So have no fear Debby, your capacitor should have enough stored energy to start your engine, hot or cold. But why did it not start...


Sounds like I'm not finished with the electrics. Perhaps a good thing to check next is the alternator leads. Their bullet connectors hang right under the air filter and were looking pretty oily and dirty...

Fix one problem, move on to the next. And so it goes...

Not open for further replies.