Vintage Motorcycle Eccentrics

For the 2 or 3 times a year that I have to do this the cheater pipe works ok. Actually with the .006 interference fit, the nut really doesn't really do that much more.

And a scale with the cheater is just as accurate.
I'm still learning from everything you choose to share.

Gordon

I hope you are learning from my mistakes Gordon, I make too many of them, still

Have quite a few places that hurt from my mistakes in judgment a collection of things that remind me of equipment failures.
I appreciate learning from other folks mistakes.

Had a very good machinist tell me he could teach me to be a machinist in about 6 months. It would take me the rest of my life to learn how to fix the mistakes I make.

Gordon

The crank is finally finished. The timing side is within a half thou and drive side .001". Now I can move on to setting the crank in the cases with 'setup bearings' to check that the rods are centered in their bores. These bearings have been ground od and id for a slip fit in the cases and on the main shafts. Shims will most likely be needed on the drive side.

The OSSA engines require ‘dummy’ bearings to get proper shims also. Not only crank but gearbox. I understand they are quite picky on getting it right.
I could see where the Vincent engine could really need the rods centered well.

You can see from the crankshaft drawing, both E192 (light blue) roller bearings have a narrowed outer race to clear the nuts on the flywheels. These races are well known to work loose then rub on the flywheel nuts.
A modification I do is to add three 10-24 flat head screws outside the race so part of the screw head overlaps the race.
I have turned the outer race of my setup bearings to the same dimension as the E192 race.

Back to centering the rods in the bores, I have a total of .019" end play. Luckily, all shimming will be done on the drive side main shaft leaving .003/.004 for expansion / contraction of crank cases. With this all set, it's time to check the alignment of the engine sprocket with the clutch sprocket. The gearbox is getting a new main shaft and the clutch sprocket has new bushings so there is a chance some shim or machining will be required.

Aligning the primary sprockets isn't super critical but it is important that the clutch drum sprocket is alligned correctly since the middle row of the triple row chain is what drives the generator sprocket.
Along with making sure all the gears are meshing full depth it is important that there is a small .005" gap between the G6 gear on the main shaft and one end of the G4AS output shaft as this is the only way oil can migrate to the bushings inside the output shaft. Too much gap and excess oil leaks out between the inner main shaft and the outer output shaft. There is a mod for that I will go into later. Spacers G19, G20/2 and E76 are made in different thickness to help fine tune it all.

After having second thoughts on using the old G3 main shaft with worn splines I ordered a new one. This along with a new clutch shoe carrier should improve the clutch operation even more.

Now it's time for the o-ring mod that helps keep oil from the gearbox getting into the clutch. A problem that has plagued old bikes for years. The o-ring will be crushed in the beveIed cut in the spacer. I will still smear a thin film of Yamabond on the splines for additional sealing.