I've been jammin' the last few weeks to get this WR engine done so I can deliver it to The Mama Tried Motorcycle Show
on Feb. 15-16 in Milwaukee. This particular engine has some documented race history with a top 5 finish in the early 1950s at the legendary Springfield Mile.
After repairing the engine cases, machining, measuring, etc. Almost every part on the engine has required attention. The motor was assembled when I received it, but the parts mirrored "swap meet specials" haphazardly assembled. The ball bearing construction appears easy to conquer...but now you're dealing with hand-press-fit on everything. It's very difficult to align the cam timing marks when each cam is pressed into position. There are so many particulars that need addressed when assembling an engine of this nature. Basically, it's got to be perfect, or it won't run at all. This is the 5th ball bearing-type engine I've built (with my dad too) - and we still spend about as much time reading, as we do building the motor.
The magneto is a horizontally mounted Wico Single Fire type unit. The ignition timing is best set by
location of the piston to TDC...then verify the timing actual timing mark on the flywheel. On the earlier WRs, once the gear cover is on...you can't change your timing from the outside, since the magneto is bolted solid to the case. No rotation. The Wico cap has a #1 which indicates the REAR(or #1 cylinder) and the spark plug wires must be installed correctly.
I updated the sprocket shaft seal (from the steel reverse thread seal) to a modern type rubber-lip seal. The seal kit (from Colony) is the same as a Big Twin seal, since the sprocket shaft in a WR is the same diameter as a panhead....but runs the larger 25mm ID ball bearing. A #1205 ball bearing to be exact: 25mm x 52mm x 15mm Superblend-type bearing.
The lower pump has been checked over, blasted, washed and inspected. I painted it my special cast iron gray, installed, with breather timed. I bumped the breather ahead 1 tooth, since the piston was already about 2" down in the cylinder before it started opening (via timing mark). By one tooth advanced, the breather window opens just after TDC - to get that crankcase evacuated of pressurized air a bit sooner.