My Norton is taking shape

[oldGSfan]

Yep, still here. I finished the gearbox rebuild today. Very tedious, like a ship in a bottle. It's all buttoned up and shifting through the gears. New bearings, bushings and seals. One up and three down on the right side. On my BSA and Triumph a stab at the shifter mistaken for brake meant a downshift. At least this is upshift if I ever do that, but my brain's trained. Like that digital gear indicator?

Disassembly required some clever home built tools - taking the sprocket off means nailing a chain to the workbench so it won't spin. The clutch actuating rod goes through the mainshaft. It's super compact and these AMC/Norton boxes (from Sturmey Archer design) shift very well.

 

[dorkburger]

Just quietly following along. It's coming along beautifully.

 

[oldGSfan]

Just quietly following along. It's coming along beautifully.

Thanks, yesterday the bottom end came together nicely all fresh and cam/crank/rods are rotating as they should, sealed up tight with Hondabond as they didn't use a gasket due to end float variances I suppose.

I painted the barrels with VHT brake caliper semi gloss which I've used on several Suzuki parts (as shown in last pic) oh so long ago, as it holds up well to heat/chemical and has a nice sheen. On the cylinder head I used an old trick, dilute engine silver with acetone and dab it on with a rag and small brush between the fins. I would have left it bare but this does look better. I sure would love to own a vapor blast setup.

 

[oldGSfan]

Here's some British heavy metal

 

[Rob S.]

That's some long stroke! But they don't really move in unison like that, do they?

 

[Rich82GS750TZ]

Rob, I thought the same. Do the 2 pistons on the Norton twin go up and down together?

 

[oldGSfan]

That's some long stroke! But they don't really move in unison like that, do they?

The classic British parallel twins are 360 degree crank, they rise and fall together but fire alternately. The Japanese twins were 180 degree. There may be exceptions but I don't know of any. See pic in post 15
Bore is 73 mm (2.9 in) x 89 mm (3.5 in) stroke giving 745cc. Well my replacement pistons are 74mm now giving 765.55.

 

[Rich82GS750TZ]

I learned something new today. Thanks Tom.

 

[oldGSfan]

I'm stalled on engine assembly until I get a dang woodruff key from the UK along with some other miscellany I need. So I turned to the revolution counter.... Inside it shows last time it was fiddled with was '69. All it needed was new glass, I got glass and bezel and rubber from India for $9 but only used the glass as the rest was fine and more correct anyway. I just had to peen over the edges carefully. Painted up the housings with good old VHT chassis and rollbar paint.

I applied a bit of heat to loosen up the congealed grease and dripped it out of the little speedo and tacho gearboxes and then put a bit of fresh, will see how it goes but the drill test works fine. I could have dabbed a bit of silver inside the tacho but it's gonna have patina all over so it's fine by me.

 

[oldGSfan]

The head is on, pushrods a bit tricky to line up. Timing side is done with the chains that drive the camshaft and magneto adjusted. Magneto is now replaced with a dummy housing that contains an electronic ignition.

Wheel building a bit tedious because of lots of misinformation about the spoke arrangement. I figured it out. There's a very slight offset for the disc side, and that side has very thick 8 gauge spokes. Trueing it will be fun.

I found some paint at the local Autozone that simulates stainless steel very well. It's made by Seymour. OMG where has this stuff been hiding? I really didn't want to spend $125 per wheel for new spokes, given that all mine were sound but tarnished. They really looked ratty but I think they came out great. I will do a final touch up with a brush after trueing.

 

[steve murdoch]

Hats off to you for tackling Norton disc wheel lacing.
Remember the woes my friend went through.
http://vintagebikemagazine.com/technical-articles/lacing-norton-front-disc-rim-06-1951/

Spectacular cracks on that K81.

 

[oldGSfan]

Hats off to you for tackling Norton disc wheel lacing.
Remember the woes my friend went through.
http://vintagebikemagazine.com/technical-articles/lacing-norton-front-disc-rim-06-1951/

Spectacular cracks on that K81.

That's a very good article and helped a lot. I got a bit sideways after reading "The Central Wheel Norton disc front rim (06-1951) is dimpled 3?1 and is handed." (my italics). Mine's an original Dunlop rim and it is that same part number, but the Dunlop has symmetrical dimpling, 1x1 I think it would be called. The hardest part awaits, aligning and trueing. I think I'll need a spoke torque wrench.

 

[steve murdoch]

I know he did both wheels on his Commando and even with a second set to copy from it was a very difficult job.
I was lucky enough to ride it about 10 years ago.

 

[oldGSfan]

Well, his instructions made it a heck of a lot easier. It's all good just need a tire and a new disc rotor. I was about ready to get my old disc 'Blanchard' ground at a shop nearby but it would cost 3/4 of what a new replacement floating rotor costs, so I ordered this one. With new Ferodo pads, a proper ratio MC and stainless lines, and rebuilt caliper (new seals and pistons) I am really hoping for a good result in the stopping dept. My old CB750 is similar tech and does OK, but the lever effort is high and it feels wooden. But it beats a drum, regardless. I had a single leading shoe on my '66 '66 Bonneville and riding 2 up was iffy.

 

[oldGSfan]

Mounted the disc and the 'bobbin' or rivet fouls the bottom of the caliper by just a tad. Disappointing, trying to find out the facts. Worst case I could trim about 1mm of aluminum off the caliper, it's not a critical area and is out of view. But jeez.

 

[Cipher]

Chamfer the caliper bit

 

[oldGSfan]

Chamfer the caliper bit

Yeah been chatting on a Norton forum and a guy did that, as I sort of suspected. Also need to shave the tang off the disc pad, since when it wears down it could also interfere.. Shouldn't be so but well, that's life. I'll post a pic on what I mean when I get a chance.

 

[Grimly]

1968 bumps against 2022 and doesn't like it.
Bobbins? They'll never catch on, new-fangled nonsense.

 

[Rob S.]

My condolences. I must have missed this post, but I have been following your current conundrums with the front brake. Pics of the spokes and new disc are neat, but shots of that custom Norton paint with a certain turbo big bore in-line four in the background take the cake.

 

[oldGSfan]

My condolences. I must have missed this post, but I have been following your current conundrums with the front brake. Pics of the spokes and new disc are neat, but shots of that custom Norton paint with a certain turbo big bore in-line four in the background take the cake.

Thanks Rob. Hey I have some goodies you might like. I will message you.

The seat has new foam and the base is patched with some sheet steel, rivets, bubble gum and baling wire. Well JK but it's fine, the bottom of the seat had cracks all over since Nortons rattle like that paint shaker at the old hardware store. I used 50-something firmness foam and cut up a yoga mat for the bottom inch. It's too soft, the place I went had 70 firmness and I blew it. It's OK but dang.

The gearbox is mounted to the engine, plates had to be trimmed a bit due to a special stubby electronic ignition housing taking the place of the magneto. It's all good, what a gorgeous lump.