BMW R90S (non Guzzi content)

[oldbike54]

80 mph in first gear...???

 I don't exactly remember , but I've owned two R100'S with the highest final drive ratio available , at redline in first gear it was running maybe 60 MPH . If you were employing the highest optional 1st gear ratio , and could rev to 8000 RPM's you might see an indicated 75 MPH , which equals about 67 MPH corrected .

 Dusty

[Brand X]

I don't exactly remember , but I've owned two R100'S with the highest final drive ratio available , at redline in first gear it was running maybe 60 MPH . If you were employing the highest optional 1st gear ratio , and could rev to 8000 RPM's you might see an indicated 75 MPH , which equals about 67 MPH corrected .

 Dusty

Look up ratio of the stronger 4 speed gear box.. It's what he used in his race bike..

[oldbike54]

Look up ratio of the stronger 4 speed gear box.. It's what he used in his race bike..

 OK , but I'm guessing it is really close or even identical to the "sport" ratio 1st gear for the 5 speeds.

 Be right back

 Edit . The standard 1st gear ratio on the 4 speeds is 3.9:1 , the 5 speed sport ratio is 3.4:! . there may have been a sport ratio for the 4 speeds providing a close ratio gear set , or he may have used the 5 speed sport 1st gear . Still , an honest 80 MPH in low gear would be hard to achieve .



 Dusty

[Cam3512]

Who cares?!

[oldbike54]

Who cares?!

 Oh hush 

 Dusty

[jas67]

..... Best thing you can do for R-90 /100 is to lighten the flywheel. They shift ten times better. Way less clunks in shifting.

BMW lightened the fywheel starting in 1981.

I had 1994 R100R Mystic, and 1992 R100R.   They definitely shifted more smoothly, but, the earlier bikes with the heavier flywheel aren't as bad you may think.   Preload the shifter before pulling in the clutch, and you are rewarded with a smooth shift.

The R100R was the most refined of the airheads, with paralever rear suspension, Showa fork from the K75, and Brembo four piston calipers, single disc in 1992, and dual 1993-1995.  The brakes were great, even the single disc '92 was very good, and suspension very good as well.

[tazio]

A most beautiful machine

[mjptexas]

Saw the R90s (Daytona Orange) in 1975 at the BMW dealer in Omaha, Nebraska.  At that time it was the most stunning bike I had ever seen.  Unfortunately, if I remember correctly, the list price was 1/3 of my current annual salary, which put it completely out of reach.

Interestingly, there was a Moto Guzzi dealer across the street that had a black V7 Sport on the showroom floor.  Arguably as beautiful as the R90s, and only 1/4 of my annual salary (still out of reach).

[Huzo]

Who cares?!

Well, to answer your question.
Dusty and Huzo..

[Cam3512]

Well, to answer your question.
Dusty and Huzo..

That’s what happens when I peruse WG after drinking sever craft beers!  At least I wasn’t on eBay...

[Green1000S]

Pretty bike, it has always been my favorite BMW. In that specific color.

[bodine99]

Since there seems to be a fair number of BMW Airhead fans here, I thought I'd share....

A good friend of mind offered to sell me his R90S if I gave him right of first refusal.   So, I brought this beauty home today!

IMG_3467.JPG by jay_snyder67, on Flickr
IMG_3469.JPG by jay_snyder67, on Flickr
IMG_3466.JPG by jay_snyder67, on Flickr

Awesome!!!

[jas67]

That�s what happens when I peruse WG after drinking sever craft beers!  At least I wasn�t on eBay...

 
Yeah, drinking and perusing eBay can get expensive!

[Winged Guzzi]

Oop's

Is that Reggo's bike? Ouch!

[oldbike54]

Is that Reggo's bike? Ouch!

 Steve McLaughlin's bike .

 Dusty

[ohiorider]

BMW lightened the fywheel starting in 1981.

I had 1994 R100R Mystic, and 1992 R100R.   They definitely shifted more smoothly, but, the earlier bikes with the heavier flywheel aren't as bad you may think.   Preload the shifter before pulling in the clutch, and you are rewarded with a smooth shift.

The R100R was the most refined of the airheads, with paralever rear suspension, Showa fork from the K75, and Brembo four piston calipers, single disc in 1992, and dual 1993-1995.  The brakes were great, even the single disc '92 was very good, and suspension very good as well.

I rented an R100R Mystic from Dubbelju Rentals in San Diego in 1995, and spent 3-4 days in the saddle.  Very much like a lowered version of my 1991 R100GS.  Wolfgang Taft (owner of Dubbelju) took time to highlight some great CA rides south of SF  for me, since I was doing this ride knowing nothing about this part of California.

The Mystic was a fine mount on which to spend my riding time in California.

I love the Beemers from that period.  So much, in fact, that at 157,000 miles, I'm having tranny and final drive work, as well as Bing rebuild and new petcocks, being done.

I bought this bike in March of 1991 from Andy Pelc BMW in Canton, Michigan.

Bob

[r90s]

My first bike was a newly purchased 1976 Silver Smoke R90S. After I crashed it, I bought a new 1978 R100S and it was equally awesome. The 3/4 seat was cool.

[twowings]

Love the red! 

[jas67]

My first bike was a newly purchased 1976 Silver Smoke R90S. After I crashed it, I bought a new 1978 R100S and it was equally awesome. The 3/4 seat was cool.

I found one of those seats painted Daytona orange last spring, and forwarded it to my friend who owned my R90S at the time.
He didn't buy it.   I wish I had it now.

[r90s]

My 1995 R100R was a sweet ride as well.

[F-22]

The Slash-Sixes were the pinnacle of Airhead models. There were flaws (remote front brake master cylinder, flexible triple clamps, weak flywheel bolts on �74s, and soft valve seats), but the overall execution is sublime. No plastic turn signals as in later models, but aluminum. The five speed transmission was long overdue and the disc brakes, too. The engine redesign placed the pushrod tubes out of sight and the 900 variant added 12-17 additional horsepower to the party over the R75/5. The Dellorto Slide/needle carburetors, gold or gray fade paint, and the Cockpit fairing of the R90S just took the design to a brilliant level. I believe that the release of this bike heralded the end of BMW�s post-WW2 designs. The days of practical people movers had ended. BMW had returned to the engineering magic that they had displayed in the late twenties and thirties, when they had dabbled in overhead valve heads, supercharging, full suspension, monocoque frames, and even Art-Deco bodywork. This trend continues even now, much to the despair of the Luddite lovers of the simpler designs. And though the newer bikes incorporate features that some of us old guys consider redundant, BMW has remained a leader in motorcycle innovations. The R90S is more than just a great looking bike...

Sorry to bash, but I can't help myself, BMW's always frustrate me! Turn signals were plastic for /6, even in your photo which seems like an original factory ad for the bikes. The /5 models had aluminium turn signals. The disc brakes were practically useless (even more due to the master cylinders) and the older drums were definitely much better (even when they went to Brembo parts in the 80's, the stainless rotors are nothing like old Guzzi disc brakes). The engine redesign hid the old exposed pushrod design to not make the engine look like it is ancient, and they kind of made it worse - all BMW airhead pushrod tubes leak sooner or later, the rubber seals eventually wear out, it's how they designed it. They did not leak as much when the pushrods were on top. Since they wanted to hide it, they might as well change the cylinder castings and remove the tubes and their sealing problems completely (practically like a Guzzi). And the fairing... It certaintly looks awesome, but is just so overly complicated to remove it... You have to remove the top triple tree, the headlight brackets, handlebar, and a bunch of stuff to get to the complex turn signal brackets and then somehow twist them out of the way (they could just make the bracket bolt onto the existing bottom triple tree clamp bolt, and it would look completely the same but removal would be a 5 minute job).



To make up for the bashing, here's an R90S I "partially" restored/reassembled for a friend:

I admit not everything is entirely as it should be (e.g. I did not work on the engine, but I hate that he had some parts sandblasted, some were bead blasted and some are still original), but I only did as I was told/paid. The bike does sound really nice with those exhausts. Also, as much as I like Guzzis, I think airheads work best with a Bing (but a Dellorto does make them more responsive).


And here's my "custom" R100RT changed into a CS:

This is my favourite BMW colour, and it was a really nice bike to ride. The black lines on the tank were a bit too thin, but It's really hard to match factory shading without experience (the R90S was painted in Germany and completely matches factory R90S shading). This one has RT-type shading (CS models were different - tank was completely black on top, but I prefer RT style). Had to use an RS handlebar to get enough clearance for the master cylinder, but I extended the stock bars by about 8cm on each end - It ended up to be a really good mix, the position was quite comfortable and controllable with the wider handlebar. The extenders were brass with a long interference fit in the original RS bars, could use aluminium but then got an idea that they'll act as hidden bar end weights. I am really happy how clean and factory-like the bike ended up being, considering how many fabrication there was (the S fairing I got was all cracked up and needed repair, I had no brackets at all for the front end and made my own stainless steel exact copies from the R90S I was working on, the original seat was all ruined ect...).

Also have a completely original monolever RT,


and an R80GS.




BMW's are really nice as long as they run, but if I do any work on them they always make me wonder why they complicated everything the way they did...

[wirespokes]

Pretty bikes, F-22. You do nice work.

The push-rod tubes weren't moved to the bottom for aesthetic reasons. There was actually a very good reason: crankshaft and cam traded positions which resulted in cylinders higher on the engine providing more cornering clearance. It was a smart move.

True, the lower fairing/turn signal mounts require a bunch of work to remove, but normally that's not a necessary job. And removing the fairing is a bit like one of those Chinese puzzles - once you know the tricks it's pretty simple.

Another point about the disc brakes. True, Guzzi did a better job on the brakes than BMW, but both made the mistake of using master cylinders that were too large. The BMW brakes, even those ATE swinging calipers work well with 14 or 13mm master rather than the 16 or 17mm they came with. On the other hand, the Guzzi discs are iron , including the carriers (added unsprung weight), while the BMW used aluminum carriers.

By the way, my dad was Czech - lived there till he was 16 before moving to the USA. Sometime I'll have to visit.

[amamet]

The great Troy Corser

[F-22]

Pretty bikes, F-22. You do nice work.

The push-rod tubes weren't moved to the bottom for aesthetic reasons. There was actually a very good reason: crankshaft and cam traded positions which resulted in cylinders higher on the engine providing more cornering clearance. It was a smart move.

True, the lower fairing/turn signal mounts require a bunch of work to remove, but normally that's not a necessary job. And removing the fairing is a bit like one of those Chinese puzzles - once you know the tricks it's pretty simple.

Another point about the disc brakes. True, Guzzi did a better job on the brakes than BMW, but both made the mistake of using master cylinders that were too large. The BMW brakes, even those ATE swinging calipers work well with 14 or 13mm master rather than the 16 or 17mm they came with. On the other hand, the Guzzi discs are iron , including the carriers (added unsprung weight), while the BMW used aluminum carriers.

By the way, my dad was Czech - lived there till he was 16 before moving to the USA. Sometime I'll have to visit.

Yes, there is a specific way to work on them, and then it's kind of easy. Especially the fairings, the R90S fairing is still relatively easy to remove compared to an RS or RT, or even GS. I also think the reason for this is they wanted a more clean design with very few exposed fasteners.

With the Guzzi integrated system, I think they did not want to make the front brake too effective intentionally (it could make the front wheel too easy to block). The early small-block Guzzis (V35 and V50 with the big black plastic fuel tank cover) also had a cable operated master cylinder under the fuel tank, so it wasn't only BMW... Still, Guzzi disc brakes were always quite good and reassuring, while the only airheads I had the same feeling were the very last (R100R) with four-pot brembo calipers. My GS was made the same year, but the brake is still quite bad (it does have the biggest classic brembo caliper, but the big wheel does not help...).

[mobiker]

 

[wirespokes]

F-22 - I'd probably have to agree with you that the Guzzi brakes were better. With a little work I've been able to make the airhead brakes about as good - but that's the thing - I had to do some fiddling to make them work as well as the Guzzi.

On the other hand (speaking of brakes), the linked brakes are ok, and I understand why they were created, but I prefer having control of them as I choose. And as a bonus, de-linking makes for stronger brakes.

Sorry for the detour - back to the 90S...

[JJ]

If Moto Guzzi went away tomorrow, I would have no issues riding another airhead Beemer (I have owned 4...).  They are great sport touring motorcycles.

This is the last classic Beemer I owned and rode when I live in NORCAL (2006-2011) - '78 R100RS "Motorsport Edition" with many upgrades from C&C Racing Products in San Jose, (aka, San Jose BMW)

[jas67]

Finally, a break in the rain!
IMG_3557 by jay_snyder67, on Flickr
IMG_3568 by jay_snyder67, on Flickr

[Antietam Classic Cycle]

Just finished up a new customer's ebay purchase Eldo. He mentioned that another bike had been added to his fleet and it in fact shared space with Travman's V7 Sport on the same Haulbikes truck. Asked him what it was: an R90S! Except his is the "other color". 

Eldo:

[Chuck in Indiana]

That's a *pretty* bike, Jay. See? I can say something good about them..   
Back in the day, my friend Steve had one, and I had my Duck. We traded bikes for the weekend. Both of us were more than happy to trade back.  <shrug>