Vintage Motorcycle Eccentrics

Interesting, rim looks as wide as the rear, but maybe just the tyre is goofing me up.
Is that a 19”?

I stand corrected, It's probably a 19" Matador front wheel not a pursang. The 370 Pursang forks are different as well. And the tank and the seat and the shocks!! May be too expensive to restore to original.

Any chance that could be a Fronterra with Pursang badges?
I don’t know enough about those to tell.

The Vincent motor had a weakness where the gearbox cam plate spindle is located causing them to break for different reasons. The fix which I have done to four other motors beefs up the casting giving the spindle more support.
This will require clamping the case down to eliminate any distortion, then pre-heating prior to welding. The buildup will be peened after each pass to relieve stress.

Does the casting have a fair amount of contamination, making welding more difficult?
Aluminum?

These sand cast cases are quite porous and contain a fair amount of silica sand. The cases have spent several hours in the old electric oven baking out the oil. After welding the spindle support the cases will get baked again to get the last bit of oil cooked out of them. Next will be coating the inner surfaces with Glyptol to make sure oil doesn't seep out. Not uncommon on some of these old engines. The right side engine case has to be heated to install the cam and lifter spindles. Then the cases can be painted. Still thinking on ways to paint the cylinders and heads.

The support is now welded in place. The spindle still fits good so no distortion.

No distortion is excellent. Always a worry. Once reason I didn’t add a primary chain tensioner on the sei. They didn’t come with one (Hivoy chain) and tend to get a bit noisy eventually. But I figured a bit of noise is better than a ruined case. Plus I don’t expect to put that many hours on it anyway.

With everything else going on, I did finally get some work done on the upper frame member. After 70 years of sludge buildup in the oil tank and no real good way of cleaning it out I decided to install a cleanout. I had tried the old nuts, bolts and gas to scour it clean but was still not satisfied. I was fortunate to find a shop that had a hot tank and that really did the trick.


This will insure easy cleaning for the next 70 years.



I finished it off using POR15 top coat.


I'm still in shock at the cost for cad plating all the exposed fasteners and hardware. Maybe I should have gone with stainless steel. Just wouldn't look original.