Monday, October 15, 2012


I have gotten a lot done the past couple of days. The drive shaft is in except for welding the rear bearing plate. I went back to using the Guzzi double joints and they need to aligned to the shaft and the front and back splines. To get the shaft and u-joints at the right angle I used the single joint i made earlier first at the front and eyeballed the shaft at the rear end. this told me where the first bearing had to go. Once the plate was tacked in place I put the single u-joint in the swing arm and did the same procedure to fit the rear bearing. that then told me where the center brg. needed to be shimmed.

The next part of that process is to make sure the bearing is swiveled in line with the shaft. I used a .0015 feeler gauge. If i could stick between the shaft and brg at the front but not the back I knew the brg. had to be shifted a bit. The brg. is a tight fit in the housing and cannot be moved by hand. I used thin punch and a small hammer so i could tap the outer race to get it set properly. I can now slide the shaft in the 3 bearings by hand. That's a good fit.

Then I put the indicator on the shaft and adjusted the brg. collar and tightened the set screws to get as close to zero runout as possible. There is about .001+" clearance between the shaft and the brg. so I rotated the collar so the set screws were on each side of the indicated high spot. That put it right on target. I marked the shaft so i can take it apart and out it back.

The next job is fitting the reverse motor. I have it where it needs to go and the gears engage well. I'll make some brackets to weld to the base and bolt it all to the floor.

Reverse update:
I found that the thin floor will distort quite a bit when the motor is energized. I ended up adding a 1/8" plate under the motor and bolted it through a cross member tube nearby. This makes it all much more sturdy.

Drive shaft update 10/29/13
After all the fuss to get it right I found in test driving that there was a scraping noise in the rear u-joint. In studying it I found that both ends were not right. The front end was too high which meant lowering the front bearing. That meant also lowering the reverse motor mounts. Fixing the front pivoted the rear a bit lower which fixed the noise back there. It's not easy to get that shaft exactly right.

Tuesday, October 9, 2012


I welded in the plates for the pillow block bearings today and started fitting the shaft. It is important that the u-joints are as straight as possible from the top view. Since the shaft is offset a bit at the rear it isn't possible to get it perfect so I'll do the best I can. when I'm satisfied I'll drill the bolt holes. Then it's a matter of shimming the bearings and aligning the bearings in their housings.

Thursday, October 4, 2012

New Drive Shaft

Finally after a hurricane, a week with a cold, a week in Italy and much studying I finally am getting some work done on the driveshaft. I bought a piece of 1.125" .094" wall chrome molly tube. I got it from these guys and I cannot say enough good things about them. They took the time to measure their stock and picked out a piece that was .001" under my bearing size so it fitted just great.

I machined bushings to fit the tube and spline stubs and used ER70S2 rod to TIG weld it all together. Actually a buddy did the welding and did a great job. The pillow block bearings are rated to 7000 RPM so they should work.

More pics to follow as I start mounting it all.