Its good having friends who are engineers. I’d figured out a way to make the adapter ring for fitting the Dnepr gearbox to the BMW engine that I thought would be perfect for making sure the spline shaft was exactly centered. I sent my buddy Jon a write up explaining it and he replied that it was an excellent plan but would not do what I thought it would, I need to add two dowel pins to the plan. The pins will ensure that the gearbox slides into the exact same place every time adding accuracy that the bolts simply aren’t capable of.
The plan for the ring is as follows.
I’ll find the exact center of the 12 x 12 steel plate and drill a hole the exact diameter as the spline shaft and then slide the plate over the shaft on the gearbox and set both the plate and gearbox to be level. Then I will clamp the plate to the gearbox and mark the bolt holes. Then I will find a meaty spot in the gearbox surface for the dowel pin holes and drill mark those spots on the steel plate.
Next step is to drill out the holes for the gearbox & dowel pins in the steel plate.
Then I will take the plate and set it up on the engine using a 3″ plug the same diameter as the spline shaft that I will slide through the hole in the plate and into the hole in the clutch where the spline shaft out of the gearbox slides in. I will adjust the plate and engine so that both are level and mark the holes for the crankcase bell.
After that I can drill out the holes in the plate for the crankcase into the plate. All bolt holes on both sides will be counter sunk so that the bolts will be flush. So picture the ring from he side view which should look in your head like a 12″ x 3/16″ line. Now in opposite directions picture bolts sticking out either side heads flush in the ring.
After all the holes are drilled the next step will be to take the plate and some bolts and put it back on the gearbox and drill the small holes into the gearbox for the pins, then take the ring and do the same on the crankcase.
The mounting method will be pretty straight forward. I will insert the 4 bolts that will go to the gearbox and then place the ring up against the crankcase and screw the bolts that go into the engine in. This will leave the 4 bolts for the gearbox coming out of the ring like the studs that would have normally come out of the engine bell housing. I will then insert the pins into the holes in the ring/crankcase. Next I will slide the gearbox over the 4 bolts/studs and clamp it down exactly as would be done normally while making sure the gearbox slides over the pins to make sure the alignment is correct. Then slide the clutch rod into place (which I have to make) and its done.
I forgot to mention that I have to grease the spline shaft before I slide the gearbox into place, but that’s ok because I am saying it here.
The paste/grease I need to do the clutch/gearbox splines has finally arrived so now I have a plan and the stuff I need to follow through with it. Once I’ve drilled all the holes necessary in the plate I’ll still have to bring it to Joe’s to get the center of the plate cut out on his cnc table torch cutter thingus since it’s got to be a 11″ circle and I can’t do that in the mill without botching it.
The Christmas deadline obviously fell through both from health as well as waiting on stuff I needed to finish, but now for sure the bike will be good to go by the time the snow stops if not before.
I’m thinking about switching from Ural wheels to Dnepr wheels. They look better in my opinion and the set I have are painted a lovely shade of black. I was just googling pictures to show the difference and one of the pictures of a Dnepr that showed up is actually my Dnepr which shows the black rather well.
So here is the Ural Wheel style:
And here is the smoother Dnepr wheel:
It should be relatively easy to transfer the nice modern bearings I put in the Ural wheels into the Dnepr wheels. The other reason I think I am going to do this is because the Ural tires are pretty much worn out where the Dnepr tires have “new” tread on them – meaning I have no idea how old those tires are but the tread is perfect. On a solo bike I’d get new tires because old tires don’t seem to grip so well in the rain and I had a bad experience with that in Phoenix on the ’73 Triumph, but on this bike I can’t fall down and I ride safer now than I did out there.
I’m going to shut up now.