75' 860 engine repair

[Kuma]

Wrist pins are worn, but not the bushings (?) Perhaps bad heat treating?
I've been using 87mm J.E. 10:1 pistons. Bore is still good, so I'm looking for a new set of piston pins & rings. I thought I had put 88's in her but it's been about 10 years and other engines so.........
I am also replacing the tower bearings as the rear top one is bad.

Question/statement; The bevel shafts are different in that the front one is bored down the center of the length of the shaft and the rear is not. I can't seem to find any info about this. I replaced the front (bad bevel gear), as a set about 10,000 miles ago and at the time did not notice that the rear was not bored. All the bevel gears look great, so I cannot see as this has effected anything except perhaps removing a bit of weight. I remember reading years ago that the bevel engines had a problem getting the oil back to the crankcase from the heads, and racing engines actually ran an external line. Could this had been the reason for the bored shaft? Should I have the other shaft bored on a lathe, or plug the bored shaft? I am going to replace the cam bearings also while it is down. All the valves, bushings & rocker shafts are in VGC as I ported it and re-valved a while back.

While I have it down I will take a picture of the late model Monster Ignition set I installed to rid it of the original ducati stuff. It uses standared pick-ups on a nice fitted timing plate. Maybe someone would like to copy this set up. The engine really lit up when this mod was done.
Thanks...

[Duccout]

Hi, The 750 bevel shafts were bored, but I think that later ones were not. I always block up the hole through the rear shaft to create an oil reservoir in the top bevel. There is no worry about the oil draining from the bevel housings as it drains all around the edge of the upper bearing housing.

While you are working on the engine, it would be a good idea to solder up the oil hole in the threaded end of the rear camshaft. This increases oil supply to the rear rocker assemblies and all Vee Two cams are made like this, as well as the factory's own cams after about 1980. The front cam never had this oilway and the cams and rockers always last longer than the rears. The top bevel self-aligning bearings are prone to wear, due to the down force exerted by the helical gears. I would check the bottom bevel shafts for play too, because the circlips tend to wear in their grooves as they turn and this allows the bevels to develop play in the shafts. If so, normally all that is needed is new circlips and slightly thicker top shims.

[Kuma]

Thank you, I will solder up the cams and look into the lower bevel bearings. I had thought I would rebuild the crank, as I have heard horror stories, but it is still within limit on side play and has no up & down movement.