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Stored '83 R100 RS needs some restorative TLC

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Mike Buhler
(@16813)
Posts: 200
Estimable Member
Topic starter
 

Anyone know where I might find a replacement gas cap? I talked to BOb's and they say BMW doesn't make the original anymore so used may be the only option.

 
Posted : 02/15/2023 08:05
Bob Thomas
(@bob-thomas)
Posts: 14
Eminent Member
 

Great looking bike, should be a hoot to ride all over Canada!!  Good Luck and most of all have fun!  

 

Bob

 
Posted : 02/15/2023 11:40
Richard W
(@wobbly)
Posts: 2520
Member
 

Posted by: @16813

Anyone know where I might find a replacement gas cap? I talked to Bob's and they say BMW doesn't make the original anymore so used may be the only option. 

Used Airhead fuel caps are running about $75 due to the rarity. What I have done in the past is search Ebay for NOS plastic caps to fit Audi, VW, and other German cars. They are the same thread pattern and dia. These are usually priced in the $10 range. It doesn't matter that they don't exactly match, because I use a tank bag on most outings.

HERE'S THE SECRET: Airheads vent through the cap; automobiles do not allow the use of vented caps. So if you install an automobile cap right out of the box, within a very sort distance you'll create a vacuum inside the tank and fuel will not flow to the carbs. To defeat this you simply drill the inside of the plastic cap (the white part; not the black part) with a very small drill bit. I use a 0.010" (0.25mm) drill bit. The object is to allow air to slowly enter, and at the same time to keep fuel from sloshing out. If you drill a hole larger than 1/32" (0.75mm) some liquid fuel will escape. 

• I believe the current eBay auction number: 283426101909 will work. Use Advanced Search to search by number.

• Once drilled, the plastic caps also make the perfect emergency cap to keep in your tool tray. They have almost no weight and they won't hurt other items in the tray.

• I may be able to find an original Airhead cap for you if you want an original. 

 

This post was modified 1 year ago 2 times by Richard W

Owning an old Airhead is easy.
Keeping an old Airhead running great is the true test.

 
Posted : 02/17/2023 08:01
Mike Buhler
(@16813)
Posts: 200
Estimable Member
Topic starter
 

On eBay they were going for $100, there were a couple available when I checked. I was just reminded there's a used bike part place here, I'll go check there next time I'm in town.

 
Posted : 02/22/2023 06:51
David Elkow
(@4949)
Posts: 284
Reputable Member
 

I see that Ted Porter at BeemerShop.com has a reproduction locking cap that I’m sure is very nice, and $142. I’d pick it over a used cap for $100 on eBay, however.

 
Posted : 02/23/2023 15:47
Mike Buhler
(@16813)
Posts: 200
Estimable Member
Topic starter
 

$142 in CDN is pretty expensive.

 
Posted : 02/27/2023 13:31
Mike Buhler
(@16813)
Posts: 200
Estimable Member
Topic starter
 

It arrives tomorrow.

 

 
Posted : 02/28/2023 19:33
Mike Buhler
(@16813)
Posts: 200
Estimable Member
Topic starter
 

It's in the shed, going to get it registered today.

 
Posted : 03/02/2023 06:34
David Elkow reacted
Mike Buhler
(@16813)
Posts: 200
Estimable Member
Topic starter
 

Anyone have any good ideas for a fix to this little crack in the fairing? I hear it's ABS so would need a proper glue.

This post was modified 1 year ago by Mike Buhler
 
Posted : 03/04/2023 10:08
Richard W
(@wobbly)
Posts: 2520
Member
 

That area is a very common place for issues. I've had several of the brass inserts loosen or pull out. What I do is remove the "lower" so that it can be worked on at the bench. In this way you can do a much better alignment job... using rubber-footed clamps and straight edges.

The original JB-Weld does a wonderful job once all the motor oil is removed with alcohol. After the break is aligned, glued and clamped it should be left for 24hrs. The next day, on the back side (where no one will see) if the part is extremely thin or weak, I'll re-clean, roughen the surface by sanding, and build up another 1/4" layer of JB-Weld to thicken the panel at the break.

• Don't rely upon the split to work the Lower over the exhaust system. Go ahead and pull the front pipes. This will give you a chance to re-apply fresh Never-Seize to the exhaust nut threads.

• Of particular interest are the 2 bolts that are used to mount the Lower to the bottom 3-point bracket. The average "short M6" which you may find in your fastener box is an M6x12, which is too long. If too long of a bolt is used there, then tightening the bolt will simply "jack out" the brass insert. Those 2 bolts are special M6x10. Torque on all those fairing bolts is also limited to "screwdriver tight"... about 5-6 ft-lbs. A "10mm nut driver" is a handy tool for that work.

• Pay attention to the sheet metal panel screws. Pan heads are used in the vertical positions; dome-head counter sunk are used in the horizontal. The later have tiny metal conical washers which may be embedded in the panel paint (or not), but going back together each position needs a metal washer. There is also a hidden screw on each side near the brake hose. (In a pinch, US-sized #8x3/4 stainless will work.)

• If all else fails, I may have 2-3 of each of the fairing panels laying around my shop. They are not blue and many have rattle can paint jobs, but if you need to start over, then..... Drop me an email by clicking in the gear in the left margin. 

Hope this helps.

This post was modified 1 year ago by Richard W

Owning an old Airhead is easy.
Keeping an old Airhead running great is the true test.

 
Posted : 03/05/2023 09:04
Mike Buhler
(@16813)
Posts: 200
Estimable Member
Topic starter
 

Thank you for the insight Richard. The piece that is cracked out is one of the bolt inserts-no surprise. Upon inspection it had been fixed before but failed again. For a quick and dirty attempt I wacked in a bunch of Gorilla Glue then laid a piece of nylon fabric around the break to add support then put more glue on top. I'll be interested to see how it feels. I put the bracket on an snugged up the bolts to hold everything in the right place. I like your idea of JB Weld and may add a layer of that over the whole thing. We'll see. 

As for those 2 little bolts I think they are the correct length from the feel I had when I took them out, I will double check. 

I had no issue sliding the piece off over the pipe but your suggestion of popping the flanges and putting on Anti seize is a great idea. These are the bronze flanges and look very clean so hoping they pop off easy. Yes I do have the proper flange wrench. 

Thanks for your offer of new pieces but what are the chances of getting a colour match? Damned near impossible I'd think. Still good to know.

I will keep an eye on the screws going back in.

Do you have any ideas of a half easy way to remove the windshield? It has mostly plastic inserts now and a few added on Phillips screws. 

Thanks.

This post was modified 1 year ago by Mike Buhler
 
Posted : 03/05/2023 15:32
Richard W
(@wobbly)
Posts: 2520
Member
 

Posted by: @16813

Do you have any ideas of a half easy way to remove the windshield? It has mostly plastic inserts now and a few added on Phillips screws. 

No ideas at all. It's always a struggle to reach your hand in there just to hold the nuts. I always hated that job. (I do like the fasteners that Clearview Screens always came with. They seemed to be easy to use with a small box end wrench.)

I can tell you that metal fasteners are a very bad idea. The secret to making anything plastic on a motorcycle last is to NOT have it touch metal. You do this by insulating the plastic from the steel with a small 'rubber' pad or washer. 

• The easiest/cheapest way to get small rubber washers that I ever found is to buy the "plumber's faucet repair kits". Back when faucets had to be spun around, the sealing washer was a flat disc. These are commonly known as "Bibb Washers". You can buy a pack of 20 to 100 fairly cheaply and keep them on hand, LIKE THESE. (You might even consider lowering the stress at the broken fairing/bracket by placing 2 of these between the Fairing Lower and the 3-hole bracket.)

• The best solution for windscreen fasteners is to use all nylon fasteners (screws, washers and nuts). 

• The best solution for windscreen mounting is to use nylon fasteners with a Bibb washer between the screen and fairing. This does 3 good things: 1) Stops a lot of random 'mouse squeaking' type noise created by the plastic windscreen rubbing against the plastic fairing. 2) Stops water from accumulating on top of the dash, behind the screen. 3) Allows just enough air behind the screen to act as a defroster.

Hope this helps.

This post was modified 1 year ago by Richard W

Owning an old Airhead is easy.
Keeping an old Airhead running great is the true test.

 
Posted : 03/06/2023 04:42
Mike Buhler
(@16813)
Posts: 200
Estimable Member
Topic starter
 

Ok great, that is good info. I haven't dug very far into the windscreen yet. I was using SP1 to shine up the bike and it brought the windscreen back to very nice and took the yellow out of it. I want to get the screen off to get at the whole thing. We'll see how it goes. I'll post how the fairing fix looks later when I get a chance to inspect it.

 
Posted : 03/06/2023 06:26
Richard W reacted
Mike Buhler
(@16813)
Posts: 200
Estimable Member
Topic starter
 

The JB Weld fix looks like it worked very well. I added a 2nd coat for a little extra reinforcement. 

I remember reading in plenty of places to check the airbox. This made me laugh!

This post was modified 1 year ago 2 times by Mike Buhler
 
Posted : 03/09/2023 17:57
Richard W
(@wobbly)
Posts: 2520
Member
 

BMW = Bivouac Mice over Winter

At least you have the correct air intake snouts !! 

Owning an old Airhead is easy.
Keeping an old Airhead running great is the true test.

 
Posted : 03/10/2023 19:20
John Young reacted
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