Thanks. These forums are a rich seam of information ripe for the mining

Those forks are as rare as hen's teeth. Don't dawdle. Of course nobody else would want them, but to put a 17" front wheel on a Sport, its the fastest, easiest way I could imagine. Buy them now, before I do. (OK, I won't buy them, but you get the idea)
Magazine article on the 900SS says the fork is very well sprung, and lovely. It is a 40mm fork, which will fit your triples, and clipons.

Cheers,

I probably would grab them, if i hadn't just had my stock forks rebuilt! Really, I was hoping those wheels (in the first post) would be an easy swap. They would have been but alas they are gone.

Both magazine articles I have on 900ss mention that the forks are much better than what was on the 750 Sport, so they would be an upgrade in the first place. Since they are basically the same fork, the lowers, which accommodate the 4 piston calipers, and the newer style speedo drive on the 17" wheels, should fit onto the fork legs and damping you are changing now. You should be able to just swap the lowers. Buy them now, swap them out when you get the rest of your 17" wheel stuff.

One of the challenges in putting the 17" wheel on your forks is the speedo drive. The speedo drive that fits the 17" wheel, is wider than the old style on the 16" wheel, which puts the wheel off center. You need to machine 7-10mm ( I forgot exact measurement) off the inside of the left fork leg to get your wheel centered again. While machining is easy, getting it perfectly straight is the bigger challenge. Forks made for the 17" wheels fixes that.

Silver wheels would look better on your bike anyway, so don't worry about missing out on those wheels. Silver ones are cheap and plentiful. White ones are much more rare and harder to find.

Overseas instigation.

Cheers,

Forks are gone

I dug up the repair manual for the 1989 900 SS to confirm a few things.
- The fork is indeed the Marzocchi M1BB, which is the same as the 750 Sport, but obviously the sliders are different.
- the swingarm looks to be different from the Sport. It looks just like the SS series that followed it.
- the rear wheel is stated to be 5.0 x 17", not 5.5 which is common for all the bike to follow it. This makes that white wheel really rare. The front is a 3.5 x 17"

For what its worth.

Cheers,

Hi Ducinthebay,

Your so lucky to have that rare documentation!!!! I can not find such a manual. Are you sure about the swingarm? To me (on fotos) they look like modified 750 sport swingarms. The 900 ss swingarm is much wider than the 750 sport so it can pivot in the much wider 900 engine as you already stated.

Strange that the manual gives a later type swingarm!? Huh?

Cheers Joep

My sources are:
- Photocopy of the 900ss workshop manual, which of course is only line drawings, no photos.
- Performance Bikes magazine from Britain, October 1989
- Australian Mototcycle Nes from August 1989.
(all purchased off of e-bay)

The pictures show the pinch bolt is ahead of the pivot pin, like it is in the later model bikes. The fitting is clearly a casting welded onto the extruded swingarms. The Sport and F-1 had the pinch bolt behind the pivot pin.
It also shows the swingarm closer to the frame, as it is on my bike that has the later model 900ss swingarm on it.
The tests, and the manual state that the swingarm is aluminum.
The axle and adjuster plates look the same as the Sport though, similar to the steel 750 SS swingarm also, so this swingarm may have been made for only one year.

I have not seen a 1989 900ss in person, I am just going on what documentation I can dig up.

I have a later model 900SS swingarm on my 750 Sport, so I know all to well what the differences are, and what it takes to get that swingarm to work on that motor. I'll take some pictures and make a post so everyone can see the pain I have suffered, and steer other clear of the problems that I have discovered.

I'll also scan the magazine articles and get them posted in the FAQ section.

Cheers,

A rich seam of information. Cheers!

Hi,

Thanks for pointing that out to me about the pintch-bolt. Your right. I have never noticed this. I have looked only at the adjuster plates and the way the huger is mounted and concluded it was a modified 750S swingarm. But now I known that also the pinch bolt area is different in construction.

I thing you are right about that they were in production for only one year.

Cheers Joep