Girder

Started looking closer att the girder fork i bought. There are some parts missing, the top yoke and the steering stem column/axle,

I have not found any pictures of the same forg model, for reference, on the internet or in any books I've got. Have asked a couple of "experts" but the only ansver I have got is: -"looks like it´s made by som Swedish blacksmith". That does not help me mch.

The data I really would want is the lenght ocf the top linkage arms and if possible the steeering axis angle. As it is, I probably will make the upper linkage lenght somewhat shorter than the lover ones, to make the fork parallel to the steering stem. Or maybe I will simulate the action in some computer progarm.

Anyway. The axles are not good, besides I'm missing one axle, the other tree all have some issues.

To the left. The original 3/8 BSC thread has been re-threaded to UNC
The one middle is the least bad one. The 3/8 thread cleaned out pretty well.
The one to the right, see below.

The axle is very worn and the 3/8 BSC thread in a bad state.

Thougt I should give the thread a try just for the fun of it and it turrned out pretty good. That does not matter since the axle is bad anyway. And since it is the same model as the missing axle, I think it's not much more work to make two of them at the same time. Now I have to find me some 1/2 inch axle to start from.

The lubrication slit will be a challange since I have no milling machine. Migt replace it with a bushing instead.

 

Magneto

In my quest for sparks I have started piling up useful things. Junk might be a better word.

Todays visit to a swapmeet got me a SEM magneto and a brand new 18mm Lodge spark plug that might be useful for the 350cc engine.

Yesterdays swapmeet got me a brand new ignition coil, that might fit the Wico magneto that came with the 600cc engine.

The used coil at the bottom..

At last weeks swapmeet I got me a pile of used and new spark plugs for both engines.

Forks

Even though the update frequecy on this blog is close to infinity, the project is not completely dead. I am constantly looking for possible parts for the project. Today I bought a girder fork, or at least half of it with the intention of making the missing parts myself.

Sorry to say I do not know from what bicycle, moped or motorcycle it came. Neither did the seller. Would have been easier if I knew how the parts should look like.

If the knowledge is out there, please let me know the make / brand.

Exhaust nut test

Made a new sample nut from high grade aluminium. My intention is to make a final version as soon as I get new, suitable insers for making inner thread (managed to damage the only one I got). Otherwise I will have to use this one and maybe make a somewhat larger dimension hole for the exhaust tube.

Exhaust Nut

Had to cut into the nut to get it loose. That does not matter since it is wery corroded and has to be replaced anyway. Thread is 20 TPI and I measured the outer diameter to 44.3 mm which I presume is  1¾ inch (44.45mm).

The new nut will be made from brass or brose. it will also be made for use with a hook wrench insted of a regular spanner.

At the same time I dismantled the valve gudes and destroyed my valve guide tool that was special made for another engine ..

Carb

I'm not sure the carb can be fixed. It's heavily corroded and I suspect the main jet can't be dismantled without destoying the threads or something worse.

Cheap fix

Since the Mark III engine was stuck, my fear was that the cylinder had been flooded with water and was a complete rust-disaster. At least the air filter was full of water...

Guess what, the rust was not that bad even if it is very worn and has some damages, it probably could be made to work. Only had to spray with penetrating oil and wait a couple of minutes to free the piston.

After some light grinding with 400 grit wet sand paper soaked with WD-40 (oil), the damages are clearly visible.

Annealed copper cylinder head gasket lightly sanded.