Just to add to the final drives on the GL1800, there are tons of trike conversions over here and the Goldwing is the #1 bike to convert.
Since many of these are being converted directly off the showroom floor, there are just as many "take off" rear swingarms complete as well as many final drives.
This is a final drive off a fairly new GL1800 that sold on eBay for $49.00.
Here is a complete swingarm that sold for $99.00. The place selling this had 3 to sell at that price and condition. Other pictures showed that the rotor still had the factory grinding pattern which would lead me to believe that it was road tested at the dealership and then converted to a trike.
The retail price for a complete GL1800 swingarm as shown, including the shown driveshaft, is just under $3,500.00. Compare that with the $3k for a "refurb" BB and it becomes clear that if M3W spent the time to modify and mount a GL1800 final drive as their BB they would have had a dependable unit at about the same price point.
Also the final drive gear ratio on one of these is 2.75:1. This would require a rear pulley ratio of about 1.2:1.
At that price one could afford to play around with the final drive to make a front mounting plate that also doubles as a front bearing mount for the drive shaft. A drive pulley could be easily mounted on the studs for the rotor and wheel. The four bolts in front are more than enough to support the final drive and drive belt tension. Let's face it, the same four bolts now support the complete rear weight of the Goldwing.
MMC buys a Miata M5 transmission and makes the adapter to hold the flywheel etc, so doing a similar setup for the BB and using a GL1800 final drive would not have been out of the question.
It's too bad that the Quaife BB is so problematic. It does seem like there are many more bad than good ones.
If Z doesn't have any luck with the refurb BB, I'm sure that his machining design skills will show us all how to install a Honda GL1800 final drive on a M3W.
Good luck with you updates and I truly hope it does not come down to that for you.
