Boxerworks.com

robert wrote:A plush but "sporty" touring bike. A bit too pudgy for a "cafe racer".

"Plush but sporty" might best describe the RS.
Certainly the 1/4 fairing of the S model (a sport fairing in BMW ads)
functions adequately to move it's design-style away from any popular definition of a "touring bike".

"Pudgy" might well describe any production airhead ...

The fact that the R90S was marketed by the factory
(esp. on the heels of the Butler & Smith # 83 BMW R90S victory in the 1976 Superbike series)
as "the most exciting machine BMW has ever produced"
and further, "it reveals it's status on first glance with it's race styling and special custom paint job" –
substantiates BMW's intention that the R90S aspire to the classification of a "production cafe".

One might quibble as to the success of BMW's venture, but the fact of it will remain.

vanzen@rockerboxer.com wrote:

robert wrote:A plush but "sporty" touring bike. A bit too pudgy for a "cafe racer".

The fact that the R90S was marketed by the factory
(esp. on the heels of the Butler & Smith # 83 BMW R90S victory in the 1976 Superbike series)
as "the most exciting machine BMW has ever produced"
and further, "it reveals it's status on first glance with it's race styling and special custom paint job" –
substantiates BMW's intention that the R90S aspire to the classification of a "production cafe".

One might quibble as to the success of BMW's venture, but the fact of it will remain.

It was certainly considered so by the press at the time.

Major Softie wrote:

vanzen@rockerboxer.com wrote:

robert wrote:A plush but "sporty" touring bike. A bit too pudgy for a "cafe racer".

The fact that the R90S was marketed by the factory
(esp. on the heels of the Butler & Smith # 83 BMW R90S victory in the 1976 Superbike series)
as "the most exciting machine BMW has ever produced"
and further, "it reveals it's status on first glance with it's race styling and special custom paint job" –
substantiates BMW's intention that the R90S aspire to the classification of a "production cafe".

One might quibble as to the success of BMW's venture, but the fact of it will remain.

It was certainly considered so by the press at the time.

I now have one, (the one I made) and it is a very nice bike. It is a blast to ride. That said, within the next year, I plan to add rearsets, a 1 1/2" lower handlebar, and hopefully, a bump stop seat so I can actually use the acceleration it has. Mine will then be what I think of as the "S" of the "S" model. In other words, that would be the next step of what BMW would have done.

Chuey..........I still don't know how to look at the bikes on that site.

Trying to figure out how they got the center stand to work on
"BMW R 80 (MIOB, Netherlands)"
I'm thinking of modifying my 2 into 1 to go from the right side to the left like that. This would make it possible to lengthen the primaries and the main pipe for better lower end and mid range torque. It would be nice to keep the center stand like they did in that picture.

Matt, you're running a Mac 2into1, aren't you? How would you grade it's sound/performance? Did you need to change the jetting? Is your bike still 900cc? Tasty bike!

Tim Shepherd wrote:Matt, you're running a Mac 2into1, aren't you? How would you grade it's sound/performance? Did you need to change the jetting? Is your bike still 900cc? Tasty bike!

Odd.....I had a big long reply that I posted. It disappeared.....? I'll type you a new one Tim, when I get a minute.

Tim Shepherd wrote:Matt, you're running a Mac 2into1, aren't you? How would you grade it's sound/performance? Did you need to change the jetting? Is your bike still 900cc?

I did a lot of mods last spring. 336 cam, Motoren Israel 1000cc Nikasil kit, titanium valve retainers, 83 transmission with light clutch gear, and dual plugging. I already had 38mm Delortos, the Mac 2 into 1, an Enduralast charging system, a crank mounted ignition, and a 32/11 rear end. I'm very satisfied with the bike now. Great throttle response at all rpms, lots of extra power in the mid to high rpm range (scary at full throttle).
I put the Mac on over 20 years ago. I did not need to change the jetting on the original Bings. The sound is awesome...not obnoxiously loud like a Harley, but it has quite a growl....especially with the fiberglass packing removed.
It is a durable cost effective system. I swear it gives me added performance and smoother throttle at curtain rpm's but this is much debated.
After researching exhaust tuning, I have found some short comings in the system. For street sport riding the primaries are too short (about 7 to 10 inches). The collector is not as smooth of a transition as it could be, and the main pipe could use a little length. The muffler core is also too small and the baffles that hold it in place are flat instead of conical. I plan to do a little modifying using parts from Megs. http://www.coneeng.com/motorcycle_components.html
We'll see what I come up with. One day I plan to make my own complete system

Thanks Matt, you should definitely document any modifications you make to your Mac and post them here.