Hello people.

Well, I guess it's now time for a word from our sponsor. Just kidding, Paul has done a great job with this site.

The bad news is there is no music news. The good news is that I've decided to see if there are any mech heads out there that visit us here. If there is and you do, let me know and I'll progressively detail the evolution of the dinosaur for you over the past twenty years. If you're that way inclined it's been a fascinating learning curve.

Meanwhile, to give you something new to read here on the site, I thought I'd start off with the current, forced engineering exercise, the redesign and upgrade of the diff, the universals and Nolathane replacement bushes.

Pic of differential on Harley Trike.
What you see pictured (Left), is not a bad idea, it just wasn't thought through thoroughly enough. And the fabrication tolerances left a lot to be desired. The centre was a Mini cage using standard Mini centre pin, planetary gears and output gears and shafts bolted to a custom drive plate carrying a custom cog of Servi-car specification and enclosed in a purpose-built cover. The unit was supported each side by sand-cast alloy carriers that used standard diameter Mini, inner and outer sealed bearings.










The standard Mini system uses rubber moulded over a cruciform steel centre as a universal joint. In a vehicle the weight of a Mini they should be checked/ replaced every year…………I didn't know this.

Probably due to the huge weight reduction in my application mine lasted seven years. I did have them inspected earlier in the year and was preparing to replace them but the internal damage was far greater than any of us realised.


Pic of rubber universal mount





The problems arise from the rubber breaking down internally and allowing excessive movement, compounded by the shape of the standard diff output shafts that, for reasons known only to the designer, (cost?) reduce to half diameter through the shaft carrier, only to return to full diameter just before the end of the snout. With no internal support, rubber breakdown and a drive plate that was twenty thou. out of round (at sixty M.P.H. this is NOT good) the end result was the destruction of the drive plate snout. By the time it started to squeak the damage had been done. Time for a new cage and a more robust and tighter toleranced design, as well as repairing and truing up the drive plate, Thank God for:





PH: 0414-74-7621











W. A.

PH: (08) 9370-2882









Pic of output shaft carrier




By the way, as well as the technical process, throughout this piece I will be acknowledging, in serial fashion, all the people who, either through full sponsorship, or through generous discounts on time, money or both, have contributed to the creation of this element of my kinetic art.

While John was busy repairing and truing the drive plate, my newest, very best friend Peter Gorman became my chauffer to whisk me thither and yon, all over Perth , in search of various bits and expertise. The first stop was:






S. T. F.





PH: (08) 9418-6655








to find out what my options were. This is where I was made aware of the Hardy-Spicer conversion to PROPER universals for Mini's. The other benefit of the Hardy-Spicer units is that they maintain full diameter for the length of the output shaft increasing strength and reducing wobble potential to a minimum. I had one of the alloy carriers with me and a quick check confirmed that the output yokes were too big for the standard bearings and that the bearing hub wall was too thin to be machined out to accept the larger bearings.



Since then, every request has been granted. Talk about Angels. But this was going to be the biggest yet.

The new plan depended on the donation of two pieces of 10 mm thick 316 stainless plate large enough to become the new carrier uprights and two pieces of 98 mm diameter 316 stainless round bar that would become the bearing hubs. Then we needed someone to cut it from my template. Once again, Alan, the silver tongued devil with the database that puts mine to shame, (and that's saying something) found another Angel in the form of:.




Conno graciously loaned me a gear, shaft and yoke and told me to take them home and have a play; next stop C.B.C bearings to find out if bearings existed that matched the required inside and outside diameters. After a three day global search the answer was yes, in America , at $800.00 U.S. per bearing.






I decided to contact my major sponsor :



Pic of stainless steel ball joint on Harley trike.






These guys came on board about three years ago starting with the donation of a pair of stainless acorn nut blanks that were transformed into the top ball joint retainers.











Cnr Baile Rd & Modal Crescent

Canning Vale. W.A.

PH: (08) 9366 - 6742 (Jason Kennedy)





On the right you see the difference in the bearing hub sizes and why it wasn't possible to simply machine the original plus, being sand-cast, it couldn't be welded. At this point John had only roughed out the bearing hub. You can also see how laser cutting allowed for really tight radiuses on the new carrier. Now we were starting to get serious and I was starting to get excited.









Pic of Hub and torque rod.
Pic of bearing hub






STIRLINGS kindly provided the stainless steel and:


1 - 7 Buckley St

Jandakot. W.A.

Ph: (08) 9417 - 9008 (Stacey Arnold)

found enough time to copy my template into their CAD system and plasma cut the carrier plates for me.

(Paradox? Agricultural motivation meets High Tech.)


The final shot is of all the components, which now included a heavy-duty centre pin and John's new hi-tech, weight-saving plastic cover. The yokes spent some time at:

This next pair of images hight-light John's bearing hub and upright work to maximise surface contact area and improve weld penetration, as well as Percy Hillbrick's welding of the hub and torque rods. For the sake of aesthetics the hubs were welded on the inner faces only.

Zoom in, it's worth it. Just click on the image.


Pic of alloy and new carrier, plus new bearing hub.




PH: (08) 9493-4390










Pic of carriers. output shaft etc pre-assmbly.
The carriers spent two weeks in my shed having been treated to Dremel and file finishing and the removal of laser and weld burns. I then gave the whole piece a satin finish.








Pic of test assembly









Finally , after a test assembly on the bench by John and a couple of test fits in the bike for John to get the final spacer measurements,




Pic of assembled new rear end on harley Trike














All images this page Copyright © Jeffrey St John

Copyright © Paul Close 2002-2016


I would like to take this space to, once again, thank everyone involved in helping to keep my mechanical mistress functional and helping me create another unique element in the kinetic art that is my daily transport. Below you will find the business cards of all my Angels. Click on the respective card to see the larger version. If you have need of their services don’t forget to tell them how you found out about them. Hope you enjoyed the story.


Stirlings Australia business card


Business card of Speciality Threaded Fastenings.
G & Y Press and Die business card
Turnaround Maching Services business card
Minicraft's  business card