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1974 r90/6 resurrection.

Roguetek

New member
So, I finally have the r90/6 home, and am gleefully taking it apart.

I note that all the fuel lines need replacing, and that the starter button doesn't.

Also, it's got the really weird switches on it.

And an aftermarket front brake master cyclinder, with no connector for the front brake light switch.

but my first concern is doping out the starter.

The battery holds a charge, and everything else lights, turn signals, neutral switch, all work. but when I push in the right hand button, nothing happens. Am I doing something wrong?
 
Yes, knowing the pinouts, you can put 12v across two terminals and read the continuity across the other two. From Haynes, it appears that 12v goes across pins 85 and 86. If working, you should see continuity on pins 30 and 87 go from open to closed.
 
thanks.. I gotta go get some fuel line, the old stuff is buggered, and a nap. I'll attack in detail once I've rested.
 
Couple of thoughts -

Put a volt meter on the battery and watch what happens when you press the starter button. The battery might look like it is holding a charge, but not be able to deliver under load. If it drops way down, say below 9v when you press the starter, its the batttery.

Next is the starter relay. You can clean up all the pins and connectors. If the red wire is corroded, it will cause the symptoms you describe. A new starter relay is $10 from Motorrad Electrik, so I wouldn't mess with the relay too long if you think it is the probelm, just replace it.

Also, on the 1974 models, the front brake light switch is a silver plunger switch that screws into the right handgrip and is covered by a rubber boot that is very difficult to get on and off without ripping. Some 1974 models have a pressure switch in the front of the under tank master cylinder, but there are no wires connected to it.

if you can, post some pics as you work.

Barron
 
IT RUNS!

I put in the new starter relay, and I was just going to see if it cranked over...

So I jumper it off to a power supply, and give the starter a tickle... 'thump-thump-thump-POP~'

"holy -Bleep-!" I sez... "it actually -fired-."

My curiousity dangerously inflamed, I reached for the jerry can of high-test I keep for amway salesmen, jehova's witnessess, and other special occasions. I fill the tank, which was bone dry, and rust free, if somewhat aromatic with decayed gasoline.

the lines begin to leak... "no problem!" sez I.. I whip out from fresh 7mm cloth wrapped line, and connect everything proper like, with my one exception of routing the crossover -around- the airbox ( because it gives me a foot of spare fuel line in an emergency, that's why)

I re seat the tank, and flip the petcocks.. each side gives a squirt of clean gas, and the lines go on.

the right side carb began leaking, but a few whacks with a hammer freed up the float, and it stopped.

"now" I sez "let's see just what the germans made." I set the enrichener, and thumb the switch... a staccato popping fills the air as one side begins to catch intermittantly, and then the other side takes hold, and begins to fire as well.

IT runs! Smoothly, even.

everything's out of adjustment, and the front end is so sloppy it's terrifying, but it -runs-.

runs, shifts, and drives.

known problems, so far.

1. front end needs a -full- rebuild.

2. horns have been removed, no new horn fitted. this must be fixed.

3. oil change, tranny change, rear end change.

4. at some point, new pushrod rubbers, it's drooling down the sides of the block.

5. new kickstand spring.

6. New battery

Oddities...

The bike has what look like aluminum spacers at the bottoms of the cylinders. not sure what this would do, other than possibly lower compression

there's a data plate inside the fairing in -arabic-... I have no idea what it says, but still -arabic-.. I wonder where this bike has been, and what stories it could tell...
 
My bike had "spacers" and base gaskets should only have 1. If they're about 1mm thick intent was to drop compression to run lower octane gas. (I'm getting rid of them on my 74 R90/6)

Sounds like you're making great progress! Here's my baby as of last weekend.
ImageUploadedByTapatalk1359759188.834908.jpg
 
OK, here's some interesting bits...


20130202_170516.jpg

I can't tell if it's an arabic data plate, or just a plate with arabic on it that they used to secure the plug.. thoughts?

Also, what are those really thick shims at the bottoms of the cylinders for, lowering compression? my r90s motor doesn't have em.

20130202_170728.jpg
 
Looks like some sort of accessory plug?.

The spacers your seeing are to lower compression to use 85 octane gas. If you look at the parts fiche online at maxbmw.com you'll see them along with a brief blurb about what they are. Snobum has a good write up on his site too.

Have a good one,
Dave
 
I'd post a picture (maybe the one you have) of the plate with Arabic writing in the Campfire forum and ask if anyone can interpret if for you. The plate is obviously a for the electrical connections. Maybe Luftmeister or Vetter licensed the manufacturer of their equipment to specific places in the Middle East. :dunno
 
Maybe Luftmeister or Vetter licensed the manufacturer of their equipment to specific places in the Middle East.

Luftmeister may have. Vetter did not license anything to any manufacturer. We did however do proprietary fairings for several of the major manufacturers (BMW, Kawasaki, and Yamaha) until 1982. From that point on the writing was pretty much on the wall with regard to the after-market fairing/saddebag industry ... they started designing/manufacturing their own factory-installed touring gear.

That connector, btw, is nothing we ever used; VFco used Molex almost exclusively.

P7190005.JPG
 
And from Luftmeister

The plugs were basically the same as the Vetter...since the Lufty was a "direct" ripoff:
 

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The plugs were basically the same as the Vetter...since the Lufty was a "direct" ripoff:

Just to be clear... Butler&Smith obtained and modified a Windjammer and manufactured them without Vetter Fairing Company's authorization.
smiley-violent036.gif
 
got the carbs off today.

eeeeeeeew. how did this thing run like that?
20130203_141456.jpg

and inside the float bowl...

20130203_142157.jpg

Luckily, in my stash, I had a set of flat-top bings of decent condition. covered in muck on the outside, but surgically clean on the inside...

20130203_160847.jpg
 
Resurrection, me too.

i am glad you are calling this a resurrection and not a restoration. I have a 1974 R90/6 too, she had spent some tough years outside near the Hanford Nuclear Reservation in southeast Washington State, lots of weird "weathering". SO I am very much cleaning her up but not going the straight to the factory route. The '74's had those black switch gears which I think are really cool, they are also VERY simple. Just clean them up and make sure all the connections are solid.
What are your plans or ideas on this machine? Mine is going to be a rider for around town and short trips because i have a 1977 R100 that I like to run on longer distances. My '74 will get lots of hand-me-down parts. I look forward to hearing what you have in mind, which will also help the fourm help you! And now that you have a lift, wow, that is great is will be so much easier to work on. I built a bench but have to use a ramp to get the bike on it, takes two people. But right now the engine is out for some repairs like a new cam shaft because the nut before me over tightened the advance and broke the end off the cam! Geez.
Kurt
 
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