Last month I finally picked up the bike of my dreams ... a 1975 R90S. It was a one owner bike purchased from the Mid West with 65K miles on it. As far as I can tell it's all original with a couple of upgrades to include an electronic ignition, dual plugs and several frame and front end modifications. It is rider and runs strong. It doesn't smoke. Everything appears to be fine.
My intention is to take the bike apart, go through it as much as I can then restore it. This is going to be a rider not a show bike so I want it to perform as well as look original. The plan is to change it from Silver/Grey to Daytona Orange.
So, this blog is to document what I do to the bike step by step. Im open for suggestions as well as criticism on anything/everything Im doing. Some will say leave it alone and ride it. I understand but if Im going to ride this bike I want to know everything is up to date and safe. If Im going to take it completely apart why not powder coat the frame, take care of some of the rust and make it look like it was brand new.
The bike came with a detailed maintanance book. Most of the services and modifications were documented. To confirm the last service I went through the bike and discovered all of the fluids and filters were new and/or fresh. That made me very happy. Now its time to get to work looking at the rest.
Let the journey begin.
I know
This is my 5th bike
Not a BMW but it was my Dads and found it after 22 years storage
I thought I might be bored after retirement but now find I seem to create more and more projects
Wish I could posts more on this bike but this site is for BMW's
Tommy
I would paint, and not powdercoat, the frame. It's your bike, and your "rider", but paint, while more easily damaged, is correct and more easily repaired than powdercoating.
The average person isnt going to care if you painted or not. And frankly I wouldnt care if no one liked the powder coating. But im 68 now and dont give a ratsass what people think of a lot of stuff. If I like it or you like what you have done thats all that counts anyway. I think what other people think is over rated anyway. And all this thinking is hurting my brain now. IMHO
twocams
Yes this is a great group of people. They have helped me out several times. And lots of help on my engine rebuild on my R69S.
twocams
As you take the wires off mark them where they came from. I like using the blue painters tape. But also there are the round card board circles with the string attached to write on. Take lots of pictures/buy a box of zip lock bags. Have fun its not a race......or is it. I took 2 1/2 yrs to do my R69S but I was working part time and needed that money to do mine. S Security check was for other things.
twocams
An R90S is more complicated than your earlier projects. Electric start, more instruments, more lights, warning lights, safety features (low hydraulic fluid, oil pressure, clutch/ignition interlock, etc.), and more electrical infrastructure to make that all happen. And that's before any aftermarket farkles, "improvements", or 40 years of possible PO "make-do/good-enough" fixes have been found. Your bike certainly looks like it's in nice shape and has been well cared for, but there may be some things in its maintenance history that'll need to be undone or re-done to return it to reasonable reliability. And, besides, it's all 40+ years old, and a lot of it may be about due/overdue for replacement "just because". Can you do it? Sure. And the reality is that, unless you're inclined to pay some pretty decent money to one of the few specialists who've been around since that bike was new, and who have retained/obtained real working expertise in the arcane techniques necessary to make/keep these things running optimally, you're going to have to do it. The local roundel-equipped "unit-mover" may be a source for parts (and the value of the marque's continuing commitment to keep parts for these things in a supply chain really can't be understated), but your bike is older than nearly everyone at that dealership, and keeping your bike operating probably isn't a metric that matters much to them.
That's going to look very nice. The painter knew smoking and striping details. Is this Holt, or someone else?
That will be a Kool bike when you get done. Is that where the master cylinder is going to stay under the gas tank? I know thats where BMW put it.
twocams
That's a common spot for cracks. Check the subframe too. Up on the cross brace near the seat locking pin.
You're making great progress!
Jim K
1975 R90S sidecar rig (heavily modified)
Frame made by Hans Obermeier?
Looks great!
Those springs are period accessory "anti-dive" springs. I also see you have a reinforced swingarm. Both are possibly from San Jose BMW/CC products.
I guess the fork brace was removed at some point? The pictures above show the stock stainless steel unit.
Depending on your weight, consider stock replacement fork springs. The progressives can be stiff too.
No worries on the parts.
Your aftermarket fork brace is a Telefix. Opinions may vary, but some seem pretty confident that the devices tend to engender more fork stiction than anything else. The /6 and /7 airheads' forks and frames are pretty "flexible-flyer-ish" from the get-go, and these reportedly didn't do much to change/improve that. The PO of one of my 90S bikes had installed one, and I thought it rode badly; removing it (and selling it to the first "go fast" wannabe) improved the ride on my bike, FWIW.
Do you mind if I peek over your shoulder on this? My 76 R90S has been sitting in the garage with the front end off for the past two years. Started to work on the front forks, then "stuff happened" and it has been collecting cobwebs ever since. Trying to pick up where I left off and your progress to date has been very helpful.
Observation / Comments...........
Looks like your "kickin but" on your project! Great work so far! I know this is your first /6 and "S". I don't know if your trying for a spot on resto or just putting back as you got it. And I may have missed your comments on other posts. You have a aftermarket top triple clamp, and also a newer braced swing arm. These were a popular and unnecessary "Handling Upgrades" done in the 70's. The same with the fork brace add-on. If your vintage racing.......then yes, it'll help. Also the "S" and "RS" bikes never had gators, but a lot of BMW guys liked the looks. If you like your mods, then buy all means keep them, It's your bike! Duel plug heads same thing. In the day they helped with "detonation" when premium leaded went away. The other mod they did was to put a /6 base gasket in to lower compression. Mine still has points and single plugs, stock compression and runs fine on todays fuel. Koni shocks were to stiff for me. (I was like 150lb in the day) so I just ran stock stuff. I did use them on my 79 RS when riding two up and they worked great. Gave them to a friend who needed a set. And yes there are plenty of springs out there to fit your needs. Running stock stuff now.I do like the shock covers. Check your throttle cables where they run in the elbows coming off the carbs. They rub there and will break. Mine was made into a R45S in 79 in Florida. I do like the looks of the elbows. All you can get from BMW is a straight carb top nipple and cable to fit. Moto-Bins in the UK has the ones for yours if you need to replace. If you have the $$ just get a new master cylinder from Moto-Bins. Mine finally gave it up last year. I did rebuild it but still has the old tank (reservoir) I checked every where for one, none to be had. Should have just got the whole unit new. I love that it was covered under the fuel tank. All the racer ass's bitched in the day there was "no feel" because of the cable. Again more BS. I also have a K100 I purchased new. About 4 years ago the front master cylinder took a crap. Guess where the fluid went? on the painted radiator shroud. My 43 year old S and 39 year old RS all good, as far as paint damage, no free lunch! My seat finally needed over-hauled
and got a base and foam from Two-Valve. The cover came from Meyer in Germany. If your mirrors are shot like mine were ( it got all fogged out) plus blasted buy the miles, Meyer also has curved Bumm ones. 89 euro's each.
Wish you the best! You'll love it when done. And all motorcycle people love the "S" bikes. They were really ahead of there time!
The biggest Modification I ever wanted for my S.... I got in 1995.........The God Damn 55 MPH speed limit repeal!
The most important thing as you know..... is..... make it yours! Didn't want to bum you out, just make it the way you want. If you change
the top clamp your going to need new (used) head light ears. They were cut down to install the top clamp. The stock clamp is less than a 1/4 thick and is steel. There are some on ebay now. It'll be $100 (ears) $20 clamp. The other stuff can also be changed if you want down the road. Swing arms with shafts are cheep. All /6 bikes used the same. Just plug your lower spark plug hole, go back stock. Now if your "S" road like crap, and a bike that was designed in the 50's rides better than one in the 70's.... both ends are screwed up! Stiff aftermarket springs, too heavy oil in the forks. much the same in the rear. Those aftermarket fork braces did mis-aline / bind the fork travel. The previous owner (or mechanic) when changing the clamp, swing arm screwed with the bearings. The swing needs centered in the frame and the bearings torqued to the correct spec. Same on the front end. If you don't get the steering head torqued correct that bike will wobble like a drunk! Your going Ikon in the back? What about the front? I've been down that road. I bet it's got way to stiff springs in the front!
What service books did you come up with? If you want to look at the factory stuff I will help you. Let me know!
The Ikons look great! I am going to get a set for my '76 R90/6.
Are you going to stay with the later drilled rotors, or look for some solids (only used in '74)?
Nope - drilled rotors are preferred, in my opinion.
The wheels are completely reversible. Snowbum has some discussion near the top, below the pictures:
There is a arrow stamped on the inside (I think in the lip) The service book is very clear on making sure it is going in the right direction if your building it from scratch. (section 36 page 36-31/1) Mine has it and it is going the correct rotation / direction.
Just shot these pictures of a front and a rear rim, so theres no confusion. The front doesn't have spokes, Rear does. Both arrows and part #'s BMW stamp are buy the valve stem hole. I just remember them from over 30 years ago when I was cleaning up my front rim. it's pretty hard to reverse the rear.......but I'm sure there are plenty of duel disk front wheels that got reversed, spoke or Mag. FYI on the disk bolts....Mine have never been touched. Bolt heads are on the left. All the factory literature I have show the bolts going in on both sides. All the single ones show nuts on the disk (left side) So mount them the way you like. Nothing in the service manual on the correct way the bolts go in.
Enjoyed your last restoration on your r/60
Make sure you don't put any part upside down and that all the bolts are tight
Good luck with your new bike
Tommy
My new project
67 Sears Allstate 250
Puch made in Austria
Moto Giro fun ride
Tommy Byrnes
54 R51/3 55 R50 64 R27 68 R69US 68 Sears Allstate 250 (Puch)