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Author Topic: 1978 BMW R100/7 - Airhead project  (Read 8199 times)

Offline andrew6v

  • Posts: 98
1978 BMW R100/7 - Airhead project
« on: Apr 20, 2015, 16:13:43 »
Hi all,


I'm a on-again/off-again creeper of the forum, and thought I'd throw up a post for the Beamer I got over the weekend. I have a Suzuki SV650 as my daily driver and wanted something to tinker on over the summer (I'm an accountant, so I have no spare time over the winter), and I always loved the look of the old airheads.



Unfortunately that photo was taken yesterday, and there is still a sad amount of snow on the ground.

We drove a couple hours to pick it up, ended up picking it up from a guy in the valley whose toys are probably worth twice as much as his house. He had about 7 motorcycles (Victorys, Harleys, and a new BMW), this BMW, and apparently two Norton Commandos in boxes. He was a Mechanics professor at the local college, and used to own 14 motorcycles, including 7(!) Norton Commandos. I was able to pick it up from him for $2300, which is probably about half what I've seen for similar BMWs (in good working order) go for in my area. He also liked me so he threw in a new progressive suspension set he meant to put on but never got to it. Apparently I'm the third owner, he had it for 15 years, and the previous owner bought it new in Germany while he was stationed there and brought it to Canada. I'm inclined to believe the Germany story anyways, as the Tach has "UPM" and something like "Fernicht" (can't remember exactly) on it with no English.

It's in pretty good shape, no rust or anything (which is hard to pull off in Nova Scotia), but has been sitting for about 10 years so it needs some maintenance to get it roadworthy again.

It has trouble starting, so I'm going to flush out the old gas, and replace the brushes in the starter, and check out the points system. I'm going to see about upgrading to an electrical ignition. The bike actually runs well, but I've only been able to start it when it's connected to a truck battery cause it will kill the motorcycle battery before it fires up. The battery is brand new, so I doubt that's an issue.

Fortunately my Dad is a retired electrical technician who used to service the Navy ships, so motorcycle electronics, no matter how complex, are still not a big deal compared to the couple thousand miles of wiring and all the sensory/communcations equipment in a submarine.

The front brake is seized, so I'll have to fix that as well, and I'm just going to go through the Haynes manual I got with it and replace the fluids, and do the other suggested maintenance.

I hear the tanks can rust out easy too, so I'm going to look into lining the tank, any suggestions?

My current plan is just to get it roadworthy. In the future I'll probably remove a bunch of weight off it (without cutting anything) and look into building a new seat. For the moment I'd like to keep it two-up, but maybe in the future have two different seats, or some sort of convertible cafe hump.

I'd also like to replace the front end with a more modern suspension, but I'd like to try and keep the vintage look, probably by keeping fork gaiters on the new suspension, and similar fork ears.

Does anyone know anyone based in Canada that caters to these motorcycles or is it just the various BMW dealers? The closest dealer to me is in another province, so If I need anything (besides very basic items) I'm probably going to have to ship it anyways.

There are a couple shops in California and Florida that focus on the airhead bikes, but I haven't been able to find one in Canada. That USD/CAD exchange rate is brutal right now, so I'm less keen on ordering stuff from the states.



Andrew




Offline Maritime

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Re: 1978 BMW R100/7 - Airhead project
« Reply #1 on: Apr 20, 2015, 16:56:03 »
Welcome, I was just in your neck of the woods to see the Hip. There were bikes out and it was funny watching them ride between the 4' snow banks. Nice score on the bike and there are quite a few German cars and bikes in the area brought home by folks who bought them while stationed in Lars before they closed.
The GL Rebirth: http://www.dotheton.com/forum/index.php?topic=68337.0
CX500 Low budget Bobber : http://www.dotheton.com/forum/index.php?topic=43617.0
"Beer makes you feel the way you ought to feel without beer" -Henry Lawson
"Beer is proof that God loves us and wants us to be happy." - Thomas Jefferson

Offline andrew6v

  • Posts: 98
Re: 1978 BMW R100/7 - Airhead project
« Reply #2 on: Apr 25, 2015, 21:59:35 »
Yeah there are definitely a number of old BMWs here, cars anyway, my buddy owns an ~1988 m3 that's also a German market BMW.

Today I got the bike outside as the weather was pretty nice. My Dad's garage is currently pretty packed to work on stuff, with his Volusia, my SV650, and the MGB, not to mention a ton of junk. I took off the bags and the windshield, which makes a big improvement in the looks department, but it's nice to know they can be easily put back on if I go for a haul when it's more reliable.




Since it isn't starting great I checked the brushes, they say that 8mm or less is shot, but the brushes on mine were about 12mm so not bad. I think the starter should probably just be replaced with something more new and improved, as it struggles.

This bike is a pleasure to work on compared to the SV650 or VT500 ascot I had. Everything is pretty simple, and easily accessible. The points, and electrical system is all at the front of the engine, and super easily accessible per below.



So far I'm pretty pumped about the purchase  ;D
« Last Edit: Jun 10, 2015, 23:05:35 by andrew6v »

Offline andrew6v

  • Posts: 98
Re: 1978 BMW R100/7 - Airhead project
« Reply #3 on: Apr 25, 2015, 22:00:51 »
That last image doesn't seem to show up for me, probably because they are both quite large images. I attached it below.



The brushes are the same as the two white boxes on top of the rotor.
« Last Edit: Jun 10, 2015, 23:05:09 by andrew6v »

Offline andrew6v

  • Posts: 98
Re: 1978 BMW R100/7 - Airhead project
« Reply #4 on: Apr 25, 2015, 22:42:58 »
I think I'll look into the carbs next, there is a guy that runs a BMW shop, Chris Harris, that has great videos on youtube, that go through a lot of general repairs/adjustments that need to be done to these airheads, some of which I already need to do. I stumbled upon one regarding a certain issue that has been known to cause hardstarting, so hopefully that will work out.



Offline Ellwood

  • Posts: 293
  • Vintage person on vintage bikes...
Re: 1978 BMW R100/7 - Airhead project
« Reply #5 on: May 06, 2015, 22:05:20 »
Beemers are a bitch to start if the valves have closed up. Torque the head properly then set the valves. Make sure the timing is ok and it should start. Then dial in the timing with a light at full advance. Always disconnect the battery negative  when taking off/on the front cover....you can fry the diode board.
Adult onset Attention Deficit Disorder is my cross to bare....

Offline Ellwood

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  • Vintage person on vintage bikes...
Re: 1978 BMW R100/7 - Airhead project
« Reply #6 on: May 06, 2015, 22:07:14 »
I have a hondaman ignition for that bike if you get the itch to make the points last longer.
Adult onset Attention Deficit Disorder is my cross to bare....

Offline andrew6v

  • Posts: 98
Re: 1978 BMW R100/7 - Airhead project
« Reply #7 on: May 08, 2015, 13:13:33 »
Hmmm good to know, I'm planning on resetting the valves, but I was thinking I'd replace the pushrod seals at the same time, and I've just been trying to source a good BMW parts dealer in Canada, with the USD being strong, everything from the US comes with a 25% premium.

Unfortunately the closest dealer to me is in another province, and when I asked them for the cost of the gaskets, and seals they didn't even respond.

Yeah I always disconnect the battery when I'm dealing with the electronics. I'm no whiz, but I know enough to cut out the source when you are fiddling with the electrics.

I may take you up on the ignition, once I save up some more money. I didn't plan on buying another motorcycle for a while and it definitely set me back haha

Offline Maritime

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Re: 1978 BMW R100/7 - Airhead project
« Reply #8 on: May 08, 2015, 13:16:59 »
Andrew, try calling Aadrian's cycle in Moncton, they were a BMW dealer and can source most old parts better than the Douchbags at Atlantic Motoplex who didn't respond. They may even ship you the parts but if not it might be worth the drive to get them.  I forget the parts lady's name but she has put more than 800,000 km on one of her BMW's.

Cheers

Maritime
The GL Rebirth: http://www.dotheton.com/forum/index.php?topic=68337.0
CX500 Low budget Bobber : http://www.dotheton.com/forum/index.php?topic=43617.0
"Beer makes you feel the way you ought to feel without beer" -Henry Lawson
"Beer is proof that God loves us and wants us to be happy." - Thomas Jefferson

Offline Tim

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Re: 1978 BMW R100/7 - Airhead project
« Reply #9 on: May 08, 2015, 13:36:14 »
BMW parts are generally 1/2 the price in the US than in Canada.  I've made many trips to BMW in Rochester NY to pick up parts (made worthwhile because there were 2 of us working on our old R75 and R90's).

The starters on these bikes are massive beasts - if yours is struggling, check the battery and make sure you keep it on a charger.  Until it's running repeated attempts to fire it up will drain it very quickly.

Your tank should be fine rust-wise.  BMW lined them at the factory with ironically a rust-colored coating.  Run inline fuel filters if you're concerned, and make sure your petcocks are free flowing.

Don't spend any real money on your Bing CV carbs.  For the price of new diaphragms you can replace them with Mikuni VM carbs.  I run VM32's on my R75/6.  A bit of work to get it all sorted, but I run those carbs on all my bikes so having common jets etc. across them all is nice.
"Quality . . . you know what it is, yet you don't know what it is. But that's self-contradictory. But some things are better than others, that is, they have more quality. But when you try to say what the quality is, apart from the things that have it, it all goes poof! There's nothing to talk about. But if you can't say what Quality is, how do you know what it is, or how do you know that it even exists? If no one knows what it is, then for all practical purposes it doesn't exist at all. But for all practical purposes it really does exist."