Potential new project

[natemoen]

That sounds reassuring. but, when running 3 ohm Dyna coils, one bypasses the ballast resistor, right? I seem to remember doing that last time....I'll have to check out my own posts!

Yes, remove the resistor for 3 ohm coils. The system is designed to run on 3 ohms (that is why the early ones used 1.5 ohm coils with a 1.5 ohm resistor). Once you go to three ohm coils you no longer need that resistor because you meet the 3 ohm requirement with the coils. If you go higher than 3 ohm it will work just fine, but it will inhibit your coil energy because it is extra resistance in the coil circuit.

[James England]

you can go up in resistance just not down. Running with 6 ohms total is fine you just cannot go lower than three.

That sounds reassuring. but, when running 3 ohm Dyna coils, one bypasses the ballast resistor, right? I seem to remember doing that last time....I'll have to check out my own posts!

[natemoen]

you can go up in resistance just not down. Running with 6 ohms total is fine you just cannot go lower than three.

[James England]

Little update

The build on the 'potential new project' continues, XSives... Here's a little update.

The engine now has oil in it, although I can't turn the engine over just yet as I am awaiting two short stainless bolts to mount the oil radiator mounting. No oil drips so far though!

A PO fitted 3 ohm ignition coils but ran the bike with the ballast resistor connected. I've ordered a pair of 3 ohm green Dyna coils from the USA and plan on getting rid of the resistor itself....I'm not sure if running the TCI with 3 ohm coils and resistor will have damaged it? Any ideas anyone?

In the meantime, I blasted the oil radiator clean and painted it using VHT gloss black engine enamel (as pointed out to me by Prisoner6). I actually bought a load of domestic salt, used in water softeners, and used that for the oil radiator, as I'd run out of sodium bicarbonate. It worked just as well...



It will be connected up here soon..



Here are pix of the instrument clocks. I stripped the cases back to bare metal and was surprised to see that, although they were in good condition externally, creeping rust was evident under the paint.....



I dunked them in acid and derusted them, ready for painting......note the foam draught excluder round the clocks, as suggested on the forum..it looks like it will do the job!



The headlamp shell was dull and tired looking, so I've sanded it down and will use black engine enamel to freshen it up. I did this on a previous bike and it works well. The plastic can take 120F baking in the oven to cure the paint (as can the stater motor cover, incidentally)



Here's a pic of the bike so far...





Onwards and upwards!

[James England]

Good troubleshooting, James!

I did roughly the same thing but it was the horn wire that got squished; made it kind of noisy every time I turned on the bike.

.

I must say, it drive me mad. There are so many different wiring diagrams, the US ones are all different from the a European ones etc etc. Then I find it something I caused myself. The eureka moment was when I narrowed it down to the dip switch. I really, truly did not think I'd be able to sort it out....hence my advice to others re plodding on methodically and trying not to lose hope........

[3Phase]

Good troubleshooting, James!

I did roughly the same thing but it was the horn wire that got squished; made it kind of noisy every time I turned on the bike.

.

[James England]

Here is how the wires should have been routed in the first place.....

[James England]

Mea Culpable

Well, heat is a by-product of electricity, so . . .

Yes?.....so it's OK? I suppose current goes through the coils and they warm up a bit, do they?

Although it's 2 in the morning here, I couldn't resist nipping out to the bike shed and fiddling with wires. I checked the right side switch and found everything was fine inside. Having pored over several wiring diagrams, I realised that power is switched by the right side switch across to the dip switch on the left handlebar switch...a black and blue wire. I disconnected the block connectors on the left of the bike, effectively removing the left switchgear, and found current switched over to the dip switch when the headlamp switch on the right handlebar was clicked to headlamp (as opposed to the first position, sidelight). No blown fuse.

Then, when I need up the newly rebuilt and much crowed over (by me) switchgear on the left, here's what I found.....


Yep, I squashed a wire when putting the switch back on the handlebars, because I hadn't routed it properly within the switch. You can see the flat squashed bit in the pic. So, every time the headlamp was turned on, the current we through the squished area to earth, blowing the fuse.

I think the learning curve here for me, and perhaps others who can benefit from my mistake, is that it doesn't take much to produce totally baffling symptoms where wiring harnesses are concerned. Also that they can be entirely self-generated through carelessness and, finally, one has to keep one's hopes up and just plod on and try not to despair!!

I hope the above may assist anyone else out there who is, as I was, in imminent danger of tearing their own hair out, or deliberately setting fire to their bike in sheer frustration.

[DiverRay]

James,
I had my '79 fry a wire inside the loom! Check between the front/switch connections and the battery. That is the "large" section of bundled wire. I cut the wrap off with an Xacto knife, and was able to repair the bad wires.
To test, take your VOM from the ground lug, and measure resistance at the headlight plug. One should be Zed Ohms, the other two should be above 500 Ohms.
Nice build! I need to keep your style in mind when I start in on my '78.

[IanDMacDonald]

Well, heat is a by-product of electricity, so . . .

[James England]

And, to add to the fun, the generator cover gets slightly warm when the key switch is turned on for 15 mins or so

[James England]

My experience with removing harnesses is never good when removing them. I no-longer remove them when working on them. I figure the wires get crusty and don't like to be moved or flexed. As soon as you do, that's where the problems arise. My guess would be a short somewhere, which sucks, as everything is encased in insulation.

Yeah, ditto. The problem is that they have to be removed when getting the frame powder coated. I removed this one really carefully, without bending anything much. Everything else so far works. I suppose there's always the option of running an extra wire to bypass any short. I did that with one of the ignition coils on the last bike.

Yes, a short somewhere. I'll probably end up opening up the wires from the switch to the first connector blocks and hope its in there...but I bet it's not.

I suppose the first step is to get a UK wiring diagram! The Clymer manual I have I'd no good for this.

[IanDMacDonald]

My experience with removing harnesses is never good when removing them. I no-longer remove them when working on them. I figure the wires get crusty and don't like to be moved or flexed. As soon as you do, that's where the problems arise. My guess would be a short somewhere, which sucks, as everything is encased in insulation.

[James England]

Help request

Mmm...so a working wiring harness is removed from the bike and all the contacts cleaned. Right handlebar switch cleaned. Sidelight position is fine, with the sidelight and instrument lights .it on the clocks. But...switch to headlamp (even without the headlamp actually connected) and the fuse blows..... The starter button works. The ignition kill switch works. Just the danged headlamp switch. I've even removed the terminal block inside the switch and tried jumping across the copper terminals.... Sidelight is fine....blows fuse on headlamp.....

Does anyone have any experienced this sort of thing, or similar? What causes a fuse to blow... A short to earth?

I don't have the TCI connected at the moment but it can't be that....can it?

Wiring looms are like a black art to me... I'm having a problem even getting hold of a UK wiring diagram

[James England]

I reckon if all goes well I'm going to keep this one!