'83 R65 - Tank mounting question(s)

[tc80211]

So the old tank on this 83 has not been helpful in me figuring out how to mount the new one...

Front rubber piece is on frame, I got that much.
Front of tank seats in there.
Rear of tank has small hoop that goes down and hooks on the frame... see the attached photo...

My buddies '78 R100 has bolts that come down from tank and extension of frame where they seat top and they bolts that screw in.

I feel like there is something else missing, any thoughts?

[Bob_Roller]

The only thing you are missing, is what looks like piece of rubber tubing that goes on the metal bale at the back of the tank .

That piece of tubing is what keeps the metal bale tensioned so it doesn't come off of the end of the frame tube .

[Barry]

I don't see the two L shaped pieces of rubber that should be glued to the inner edges of the tank to buffer it from the frame tubes. Items 2 & 3 in the diagram. They go right at the back of the tank and not at the front as shown.

You can spring that bale clip open to thread on the rubber tube that Bob mentioned. That is in the diagram although I'd say it looks too short as shown.

No bolts of any description with our tanks. It's held very securely with that bale clip and yet can be removed in seconds.

[montmil]

The large fuel tank on my '78 R100S is a real PITA to remove. Worse to refit.

The aft attach for the S has two plastic, knurled nuts that thread onto short studs that poke up through a cross member on the bottom of the tank.

Not a terribly poor design but it your hands are bigger than a kindergartener, there's a good chance for a little blood. Add in finding those mutha plastic nuts when one falls into the dark recess.

I like my R65's tank install way better.

[mrbuck]

I have the 2 screw down bolts to mount the tank on my '81 R100.  Msbuck's '84  R65 has the bale with the  rubber cylinder to mount the tank...definitely easier...be glad.  

[DerekM]

So the old tank on this 83 has not been helpful in me figuring out how to mount the new one...

Front rubber piece is on frame, I got that much.
Front of tank seats in there.
Rear of tank has small hoop that goes down and hooks on the frame... see the attached photo...

My buddies '78 R100 has bolts that come down from tank and extension of frame where they seat top and they bolts that screw in.

I feel like there is something else missing, any thoughts?

So the tab that has a threaded hole is for what exactly? :-?

http://www.bmwr65.org/htdocs/yabbfiles/Attachments/underside.PNG

[Luca]

I've heard that the tab with the threaded hole was there for mounting the tank on a post during painting at the factory.

While we're on the bottom of the tank, you should know that the metal tube sticking out of the bottom is the end of the drain hole that is under the gas cap.  It's a good idea to put some fuel line over it and route that to a safe place.  If gasoline goes down that hole it can land on hot exhaust pipes.

[Barry]

So the tab that has a threaded hole is for what exactly?

I think Luca has it correct. We had a thread about this some time back and you could even see the paint line on mine which seemed to confirm what it was for.

[Barry]

So the tab that has a threaded hole is for what exactly?

I think Luca has it correct. We had a thread about this some time back and you could even see the paint line on mine which seemed to confirm what it was for.

[AlfromNH]

The 2 L shaped rubber bumpers Barry is referring to. I'm missing those, always thought the tank seemed a little sloppy just sitting on the frame.

Those bumpers are $18 each, does anyone have a picture of what they actually are? I'm thinking there's got to be a cheaper method 8-)

[montmil]

...Those bumpers are $18 each, does anyone have a picture of what they actually are? I'm thinking there's got to be a cheaper method 8-)

Yes, those $18.00 dense foam rubber tank cushions are pricey. Each leg has a different thickness and the L-shaped pieces are mounted in a specific orientation.

[tc80211]

Thanks again as always guys! Next up, brakes!

[Bengt_Phorqs]

Just a slightly off camber suggestion for those with the /6 & /7 tanks that used the two knurled nuts to fasten the rear of the tank to the frame.  Try using metric wing nuts.  The knurled nuts are easy to drop and fumble, less so with wing nuts.

[montmil]

... While we're on the bottom of the tank, you should know that the metal tube sticking out of the bottom is the end of the drain hole that is under the gas cap.  It's a good idea to put some fuel line over it and route that to a safe place.  If gasoline goes down that hole it can land on hot exhaust pipes.

My first "ahha moment" with my new-to-me '81 R65 was the same one Luca mentions.

Wondered what the hole was under the fuel cap. Stuck a lone pipe cleaned down the rabbit hole and was amazed to see it pop out atop the engine. This can't be good, sez I.

From the tank exit, I connected a short piece of tubing to a nylon "L" from Ace Hardware & BMW Emporium. A longer, discreetly hidden piece eventually wound up aft and below the swingarm pivot.

I still dismount before filling the tank on any of my bikes. Quoting ol' Frank N. Stein. "Fire bad!"

[montmil]

Just a slightly off camber suggestion for those with the /6 & /7 tanks that used the two knurled nuts to fasten the rear of the tank to the frame.  Try using metric wing nuts.  The knurled nuts are easy to drop and fumble, less so with wing nuts.

I, too, thought that would be a nifty idea so invested in a pair of metric wing nuts. No joy. The R100S tank and those wings made contact before the tank properly settled on the frame. Yep, all rubber bits are OEM and in place.

Back to those pesky knurl your nuts bits.