old R90/6

[US_Marshall]

I did not fine an introduction thread so ..... here I am.

I acquired an old R90/6, a little research shows it is a 75. It was sitting under a cover for about 5 years at a boat yard next to salt water. I am now working on patching it back together, the prior owner/rider did not take care of it. The head light was a 7" seal beam bulb ducktaped to the housing, old rust gas and rust residue in the carb bowls (fuel was off) showing he had been running bad gas through the engine. I cleaned the tank and installed a battery and fired right up. Runs pretty well for a bike that has been stashed in less then favorable conditions.

The odometer reads 2,200 miles, I wonder if has been rolled over already?


Things done:

changed oil
fixed wiring (still needs flasher relay)
cleaned carbs
cleaned tank
new fuel lines (with filters)
Make new head light (stock reflector, different glass)
remove luggage rack+back rest
adjusted valve lash
modified center stand to place battery under transmission


Things to do:
replace front brakes
new rear main
relay
new tires
Change ALL fluids

Then it is ready to hit the road.

[R100LT]

Apart from the seat ... not too shabby... well done

Enjoy

[disston]

Welcome. You are right, no intro other than right here.

Seems an innovative headlight set up. No idea what's wrong with stock battery position. Parts are available if the old battery box is rusted away.

Paint looks in great shape for a 102K bike. Can't imagine it has not been around at least once.

[Rob Farmer]

The PO wants shooting for painting the mainstand that colour Apart from that it looks ok and wouldn't cost too much to sort out. the 90/6 is a lovely bike once it's setup.

[Wirespokes]

Not a bad looking bike at all. And who knows how many miles are on it? The odometers frequently fail and this could be a replacement unit, so it's anybody's guess as to mileage.

I've never seen a headlight like that! What is it? Definitely more aerodynamic than the stock Bosch!

[Beater]

I have a battery try that will fit that .... PM me if interested. Fred

[crazydrummerdude]

Are those fuel lines super kinked in that setup?

Also, I can't tell exactly, but it looks like you've got the wrong battery in there. I had a little cheapo one in my R90/6 for a while and I had it up on a wood block in the tray.

Throw some fork gaiters on it, get some new oil and tires, switch out the fuel lines, and you're good to go.

[disston]

Notice the cut out in the air filter cover? The air filter sits above the trans and on the lower engine side there is a little hole on both sides. See it? Using a tee arrangement in the fuel lines a cross member, fuel line, goes through here. Not a biggy but somehow it looks funny with out it. When fuel gets low the two cylinders will run on their respective sides of the tank with out it. So it has a sort of purpose.

Those are later model petcocks. But that's OK.

[US_Marshall]

Originally Posted by disston

Notice the cut out in the air filter cover? The air filter sits above the trans and on the lower engine side there is a little hole on both sides. See it? Using a tee arrangement in the fuel lines a cross member, fuel line, goes through here. Not a biggy but somehow it looks funny with out it. When fuel gets low the two cylinders will run on their respective sides of the tank with out it. So it has a sort of purpose.

Those are later model petcocks. But that's OK.

I have the original T fittings and will be installed with new lines and filters after the fuel system is finished, the fuel in the tank still looks orange if i shake it up (off the bike) so it still needs more flushing.

I painted the center stand, after cutting and welding I didn't have any black paint so this was the best I had at the time.

I have the stock battery tray, it is in good condition too, the battery is going to be relocated under the transmission. The current battery is only a 35CCA but turns over and starts right up so it will stay till I am sick of it.

[US_Marshall]

The mufflers are rotting from the inside, there are holes and some odd rust cracks in it. So I decided to change the system.
I started with a header off a R1150, cut the inlet off where it is ovaled





. I added on 4 inches of strait pipe to match the old heads. The header had to be widened about 1.5" to line up. Heated it cherry red near the merge point and wedged the header apart. Welded up a new extension and fitted an aftermarket muffler.





Since the carbs need to be rebuilt, I'm going to rejet it too.


I overhaled the front brakes, new EBC pads, braided hose, cleaned master cylinder and replaced the outer seal. The rotor was grooved on the inside so I resurfaced it. It is .010 under specs now though.

I would like to replace the disc on the hub but can't find what I am looking for. Does any one have the diameter of the mounting for the 5 bolt rotor? without cutting the rivits off and mic'ing the the rotor hat I get 5.655.

[Schlivitz]

I'm diggin that bulbous headlight. Does it have any ID on it?

[bmweuro]

Originally Posted by Schlivitz

I'm diggin that bulbous headlight. Does it have any ID on it?

x2 on that groovy headlight.

[US_Marshall]

t is a Writeway lens, came off a mid 30's Chrysler (I think). only took a little grinding of the glass to fit into the BMW reflector.

[Schlivitz]

Originally Posted by US_Marshall

t is a Writeway lens, came off a mid 30's Chrysler (I think). only took a little grinding of the glass to fit into the BMW reflector.

So, I won't be pickin' that one up at PepBoys.
That's probably a good thing. It would be hard to justify from a "form follows function" stance. But if anyone can think of a functional advantage.......

[US_Marshall]

Just a crappy cell pic, but it shows the direction I am going.



The tank fits OK, I plan on modifying the front are to clear the master cylinder, the back looks like it need little work to fit securely.