Any luck coming up with a plan for the driveshaft?
Finally had some time to get back to this never ending project. A few more prototypes and some more time drafting and I think I have what will allow the use of several stock drive shafts, allow a standard cable drive spedo to be maintained, and be able to apply grease to the drive shaft bearing.
Pic #1 Decided that egging out this hole and making the tunnel material with a larger hole was not the best idea as it did not give much extra clearance for installing the drive shaft and will reduce the strength in this area in a stock bulkhead that has not been re plated like this one has.
Using the belt drive back plate for a template, it was mounted to the PTO side of the sled with the common rivet holes in the bulkhead (not shown) and used it to transfer the upper and lower flangette holes for the drive shaft and jackshaft.
Pic #2 Mounted the belt drive back plate to the Mag side of the sled. Installed the rear suspension front shaft into the tunnel and tightened it to put the tunnel into its fixed position that it will be in when the rear skid is installed. Did some checking on the back plate with a framing square and found that my back plate was not square to the top of the tunnel. Jack shaft was falling down hill toward the driven clutch bearing flangette mount. With a chain case this was not always a large issue but it could be corrected with chain case shimming to get your jackshaft and drive shaft back in square with the tunnel. As I want my back plate to be fixed to the side of the tunnel to provide more strength I did not want to shim the back plate as a chain case would have been to correct for this type of misalignment. After some persuasion with some wood blocking and a sledge hammer I was able to get the sides of the bulk head square with the top of the tunnel.
Pic #3 Took more material off of the bearing mount so the shaft would clear for install. The plan was to use the two studs to hold it into place while the shaft was installed and then add a spacer shim behind it after the shaft was installed. Final shimming to provide for no bearing side loading would be accomplished with 25 mm shaft shims between bottom pulley side bearing and the drive shaft.
Pic #4 Slide in shim to make up needed space after drive shaft has been installed. What I found at this point was I could install the bearing holder and the shim into the sled just by removing the studs and rocking the bearing holder a few degrees in its flangette. This bearing mount and shim has now become another prototype and I will be making a new one that is thicker so no shim is required. Currently this newest revision will allow the use of several types of stock drive shafts. Aluminum Pro Shaft, Steel hydro formed pro RMK shaft with integral spedo drive inducer, pro steel hydro formed driveshaft with no spedo drive inducer, and a fusion RMK era steel hydro formed drive shaft. A standard steel hex drive shaft could also be shortened to fit this also but would be the heaviest. These will all work without any provision to grease this bearing or to attach a cable driven spedo. The 2 drive shafts with bolt on inducers will require some adapter parts to get a standard cable type spedo drive and a surface for the grease seal to ride on for provision to grease the bearing. The pro steel hydro formed shaft with permanent spedo inducer will require drilling the shaft end to be able to press in the spedo drive insert and a press on sleeve for grease seal surface. The aluminum pro shaft and the pro steel hydro formed shaft with no spedo inducer would require drilling and tapping the end to accept a shaft extension for grease seal and a place to install the spedo drive insert. I have some ideas on all these that would work but have not made any yet.
Pic#5 Attachment bolts and studs on PTO side of the sled. Studs will be used to attach a spedo drive adapter. Note the drive adapter with one ear trimmed off. The drive shaft was lowered as far as possible by rotating the flangettes. The studs are in the original index position so the drive adapter will point the correct direction.
Mounting the complete bearing support on the inside of the tunnel has worked out well to minimize the size of new holes needed into the side of the tunnel. The .250" center hole should be all that is needed for the spedo drive key to get from the shaft to the drive adapter. If this was being installed on a non modified tunnel, a plate will need to be installed on the inside of the tunnel to cover the original drive shaft hole, so future bearing holders will need to be made to accommodate the cover plate.
Pic #6 Spedo drive adapter install mock up.