Topic: BMW R100 Airhead

[RAFster122s]

While it isn't a R100 article, I thought you might enjoy...

10 days with a '75 BMW R90-6
http://www.motorcycleclassics.com/classic-german-motorcycles/ten-days-1975-bmw-r90-6.aspx

[Scott S]

Spent a little time on the saddle bags recently. I ordered two replacement latches from MaxBMW; one to keep them closed and one for the latch that holds the bag to the rack.
 I thought that one of the rack latches was stretched out and busted because the P.O. kept forcing it on and off the holder rather than get a key for it. Turns out it was simply the wrong latch!
 That's probably why it allowed the LH bag to drop down on the muffler at some point.



 And in case you've forgotten, here are a couple of "before's" of the bags and busted latches.




 I repaired a couple of small hairline cracks, removed the decals, hit them with a Skotchbrite pad and some car wash and taped them up. After riveting in the new latches, of course.

[Scott S]

 I wiped them down with Acetone and Preps-All and sprayed them with Krylon Dual Superbond paint. Turned out OK. I didn't do any "bodywork", so there are still some minor scuffs and scratches, and you can see a little "tiger stripe" in the paint under the right lighting. Still....much better than before. I used some Rok-Straps for a little extra security.







 (Oh...ignore the spot in the driveway....a friends car left that there a couple of days ago. That's not from the bike.)

[Scott S]

Here's something I think is neat....
 See the rear view?




 I used some 3M reflective tape that's black in the daylight but highly reflective at night.



 I'm pretty pleased with the way they turned out, especially with the repair costs vs. replacement costs. I put about 150 miles on the bike today, over some rough rural roads and at speeds of 80+ MPH on the interstate. Very solid now.

[Scott S]

Tomorrow, I plan on checking the valve clearances (even though they only have about 1,000 miles on them since I did it last) and probably a carb sync.
I really didn't know what I was doing the first go 'round, and I have better TDC marks now (remember the flywheel being off by one bolt?). It's more of a peace if mind thing more than anything, but I do hear a little valve noise on the RH side.
It can be tough to find TDC by yourself on an Airhead! Trusty old straw to the rescue! The LH cylinder will be ready in the morning, once it's stone cold. Then I'll move it to the other side and watch it until I find my mark again.

[simon#42]

the rok straps are a very good idea  , i use these they are brilliant . the lock that holds the pannier to the frame is rubbish and will come undone on a bumpy road .
i found this out the hard way !

[RAFster122s]

Bike looks really nice Scott. Nice job on the repairs.  Did you fix the bottom of the one where it had hit the exhaust?

[Scott S]

Bike looks really nice Scott. Nice job on the repairs.  Did you fix the bottom of the one where it had hit the exhaust?

 No.... Initially, I tried. I used my heat gun to try to soften it up and mash it flat(ter). When that had no effect, I tried smearing in some of the plastic weld stuff I bought, using it like Bondo, but it would have taken a massive amount. So, I just let it be. It's invisible once mounted on the bike.

[RAFster122s]

Would roughing up the inside and putting a fiberglass patch over the area keep water out, or just silicone a patch of cloth in place... it has a hole in this area, right?
She is quite transformed from when you got her. A real looker now. If you sell her you should get a nice price for her. How do you like the handling and power? How many CCs? How are the brakes?
Is that the std BMW R100 fairing or an aftermarket. I have a friend in Sierra Vista, AZ who has an R90 he bought new.

David

[Scott S]

 The place on the bag isn't melted through. And the P.O. seems to have done some sort of patch job on the inside...or, maybe that's his melted clothes!

 While I was skeptical, I can now "get" why people like these bikes. So, SO very different than our SOHC4's, or any other UJM for that matter. Some of the engineering seems to have been done "just because".
 It doesn't feel flickable at all, but the chicken strips on the tires tell a different story. A month or so ago I was riding with some friends on the Saluda Grade (nice curvy road near Hendersonville, NC) and my friend on a modern CB500 couldn't shake me. He commented later "It looked like you had that thing really leaned over", but it never felt that way to me.
 There's no "rip you off the seat" feeling of power, but it'll get you to 80 or 90 MPH right quick like. The brakes are OK. It has the triple discs/Brembo calipers. They're...adequate. The rear is known to suck and some people  convert back to drum but, like everything else on this bike, they get the job done.

 It's 1,000cc with dual plugged heads. The fairing is a genuine BMW S fairing that someone installed. The bars are K-model bars. I get 42-47 MPG with it and can go well over 200 miles before hitting reserve. In fact, I've never had to go to reserve. I think I've gone as far as 225 miles before filling up and never needed reserve.
 The riding position is sporty but all day comfortable. The R fairing/seating position actually has better wind protection than my Tiger Xc with a Givi Aero-Flo windshield.

 This bike doesn't excel at anything, but it does EVERYthing well. I can see why people become fanatics about them.

[grcamna2]

I like that Beemer and the work you did to it Scott,a very nice all-day touring bike that handles.

[Scott S]

 Thanks!

 I spent two hours this morning checking and adjusting the valves and I should have just left well enough alone. I only did one intake and settled on a loose .004/tight .005.  Everything else was spot on and I probably should have left that one intake valve alone. Went with .004" intake and .008" exhaust.
 I'm told that noisy valves are happy valves on an Airhead. They tighten up with heat and over time, so loose is better than tight. Guess I just need to get used to the different sound from our Hondas.

 I might throw the sync gauges back on it again after the next ride. I think I have one throttle cable that keeps tightening up. I've tweaked the mixture screws and that one idle screw a couple of times trying to adjust the idle, so now my sync is probably off. Again....more for my peace of mind than anything.

[RAFster122s]

Wonder if you have an air leak on the carb that is getting leaner. Check for it with some carb cleaner or other flammable spray at the gasket area of the carb to intake runner and at the head.  See if that might be doing it.  You may have a warp that getts worse as the metal expands & heats up.

[Scott S]

I can't find a leak. The throttle cable on that side keeps tightening up and loosing freeplay. I straightened out a crook in the cable and did the carb sync yesteryear. Seems to be better.....for now.

[riverfever]

Scott this really looks sharp. Great job. Love the color you used.

[Terry in Australia]

Thanks!

 I spent two hours this morning checking and adjusting the valves and I should have just left well enough alone. I only did one intake and settled on a loose .004/tight .005.  Everything else was spot on and I probably should have left that one intake valve alone. Went with .004" intake and .008" exhaust.
 I'm told that noisy valves are happy valves on an Airhead. They tighten up with heat and over time, so loose is better than tight. Guess I just need to get used to the different sound from our Hondas.

 I might throw the sync gauges back on it again after the next ride. I think I have one throttle cable that keeps tightening up. I've tweaked the mixture screws and that one idle screw a couple of times trying to adjust the idle, so now my sync is probably off. Again....more for my peace of mind than anything.

Good job mate, your bike looks awesome. Re: your rattly valves, I had the same problem on my first (1979) R100RS, and the culprit was badly worn rockers, that I had to have built up with hard welding and re-faced.

If I tried to set the clearances once I did it 10 times before I realised why it was rattling so much, and I don't believe that my valves rattled at all afterwards. My second R100RS (1980) had no such issues. Cheers, Terry.

[Scott S]

There's also a freeplay adjustment for the side to side (up and down?) movement of the rocker arm shafts. That can cause a noisy valve train too.
 I took a look at mine the other day and there were a couple that **maybe** could have used a little adjustment, but they were very, very close and, not having done it before, I decided to leave them well enough alone.

[grcamna2]

Hows your top-end gasket look? did you re-torque yet ?

[Scott S]

 What do you mean by top end gasket?

 The first valve adjustment loosened the head stud nuts and the re torqued. This time I only torqued them, in three progressive steps.

[grcamna2]

What do you mean by top end gasket?

 The first valve adjustment loosened the head stud nuts and the re torqued. This time I only torqued them, in three progressive steps.

I was just wondering if your topend/cyl. and head gaskets are still in good cond.

[Scott S]

I guess so....no leaks from around there.

[TomsK8resto]

Scott,

Great job!  Hopefully someday I'll find one like it. 

Tom

[Scott S]

 Shameless picture bump.

[grcamna2]

What do you mean by top end gasket?

 The first valve adjustment loosened the head stud nuts and the re torqued. This time I only torqued them, in three progressive steps.

Nice 

[CBJoe]

That is a good looking bike Scott!  I really like the seat, rack, luggage combination.  Have you ridden it two up?

I need to find one to test ride one of these days....seeing more and and more old Airheads around and at the local events.