Another Basket Case Resto

themansfield

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Feb 5, 2019
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Hi Crew,

New to Nortons here. Many years in the saddle of the competition, but getting back to the roots. Recently acquired a basket case that I think is a 1970, but I’d like to know its true identity. Engine number 20M3S/132336, halo headlamp, S side covers, canary yellow. No headers or pipes to indicate it’s an S, so I’ll call it a Roadster unless anyone has more insight.

Every bit and bob is well enough beat up that I don’t have a candidate for a 100 point restoration, so I’m going for a mechanically-sound, ride-it-like-hell sort of project. I know it’s not the bike for a Mojave desert race with Mr. McQueen, but some of hobot’s off piste stories have me enthusiastic.

I’m missing all the ignition bits, so going straight to Tri-spark. Is an appropriate kill switch for electronic ignition as simple as cutting the switched power to the unit, vice grounding it out?
 
themansfield said:
I’m missing all the ignition bits, so going straight to Tri-spark. Is an appropriate kill switch for electronic ignition as simple as cutting the switched power to the unit, vice grounding it out?
Click to expand...

No, it doesnt shunt it to ground. It is a Normally Closed switch in the LH switch gear for post-71 bikes.

Another Basket Case Resto


You could do it this way with a NO switch and a horn relay, as I found it hard to find a good separate NC switch that is not part of the Lucas switch gear.

1. Connect the Tri-Spark black/yellow wire to 30 and 87a to ignition coil

The ground connection to the relay coil should be wired thru the kill button, thus completing the circuit.

2. Connect 12v- to 85
3. Connect Kill switch to Earth and 86
 
Already frying my pea brain. Is it enough to run the ignition hot lead from the stock switch to an NO switch on the handlebar, then down to the tri-spark? I can’t see how that would be any different than turning off with the stock key switch, unless that run of wire is too long or the switch can’t handle the steady flow of juice all the time.

Trying to figure out how to post some pics of the old girl. More pea brain frying.
 
Normally Open (NO) means there is an Open Circuit = no connection until something happens (button is pushed).

Normally Closed (NC) means there is a Closed Circuit = by default there is a connection until something happens (button is pushed).

themansfield said:
Is it enough to run the ignition hot lead from the stock switch to an NO switch on the handlebar, then down to the tri-spark? I can’t see how that would be any different than turning off with the stock key switch, unless that run of wire is too long or the switch can’t handle the steady flow of juice all the time.
Click to expand...

So, you would need a NC switch to do this - not a NO one. And the problem I ran into when trying to find one is finding a push button switch to handle the steady flow of juice that is NC. Most of them are NO.

So I got a good switch and used the relay to make it work.

Or you could get something like this - https://www.ebay.com/itm/Handlebar-...Light-Motorcycle-Scooter-ATV-US-/264101810862
 
Last edited:
Got it, thank you. Switch choices do seem slim.

I’m imagining needing a kill switch like I do on my other adventure bikes, but I suppose I could be disavowed of the dirt dream on the first bush run if I can’t sort the suspension first. Nothing crazy, just dreaming of some desolation tent whiskey.
 
Good luck with the project. It’s liberating when you get one far gone enough to customize. I’m into a full nut and bolt restoration on my ‘72 Interstate that is going to inhale my wallet. But I have a very very rusty Guzzi in the storage unit that I can strip and make into a bare bones cruiser in any color I choose. Someday...
 
you could always adapt a set of modern (new in the last 10yrs) handlebar switch of a UJM, it would give you all the wanted functions and are quite inexpensive...
i'm using aset off a 06 suzuki sv650
 
There are a ton of switch options. If you want a little better quality look at the Domino stuff. I have that on the Ducati and it's pretty nice.
 
Regarding the gearbox:

The mainshaft and the sleeve gear got a little too friendly (bushings nowhere to be found - only the dust remains). Mainshaft can’t be saved, but I wonder if it’s ok to Loctite the new bushings in the damaged sleeve gear and call it good. The new ones will press fit ok I believe, and I don’t think they need to be free spinning like, say, the other gear bushings. I’ve read all the posts on adding a third bushing, washers behind the circlip, bonneville bushing, oil pathway routing, etc etc. Can I get away with a simple Loctite job?

Interestingly, the layshaft third gear bushing had to be pressed out, but the new one slips in like butter.
 
Does anyone have a measurement of the length of exhaust pipe after the upturn on a Roadster? My baskets contain pipes from an Interstate, the ones that turn back horizontal before the silencer, and I’m wondering if there’s enough meat there to cut them back and install them as upswept Roadsters.
 
Thanks, Time Warp. Looks like the Interstate left pipe won’t have the length. Both left and right are about 125mm for that upswept bit.

I ended up reassembling the gearbox with two new sleeve gear bushings and loctite. I was happy with the clearances and didn’t have to do any reaming. I did replace the mainshaft, no way around that.

Powered through a 3 day weekend and a lot of beer last weekend and got the engine and gearbox reassembled and installed. Started right up. Slop in the swingarm and old clutch bearing became apparent when I sent it through the gears, so I’ll address that next. Overall very happy with the results so far. A long way from bins of parts.
 
Should have some pics up via google tonight.

Here’s an electrical question. Key off, light switch off, I get a spark when connecting the battery. I also find that the horn circuit and lighting circuits are live even with the key off. Is this normal or is something amiss?
 
Another Basket Case Resto

Nice!

Just click on your photo in the album, then right click and select "copy image address", then when you post here, click on the photo icon and paste in the http:// space.
 
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