BMW air-cooled motorcycles?

[Reaper90]

anyone got any experience with Beemer airheads?

I'm a sucker for odd things, and my whole family rides for the most part, but they're all Harley types, and I'm just not a huge fan. I love the cafe racer look, but have found myself drawn to the larger late '70's to early '80's R100 airheads:







of course with simple changes they can be much racier looking....







Anybody here with any real ownership experience with one of these? I'm a tinkerer and whatever I buy will end up stripped down and rebuilt fro the ground up as a brand new machine..... I'm just looking for some insight on real world issues that I need to look for.....

[RTHolmes]

this is definitely the way to go

[AWwrgwy]

Find an XLCR.

I did.



wrongway

[Reaper90]

(Image removed from quote.)

this is definitely the way to go

I love that look, John... but a lot of the riding I would do would be long distance highway stuff with my old man, cross country stuff. Highway comfort, saddle bags, and easy cruising are a mandatory thing. THAT BEING SAID, I'm a tinkerer.... I fully plan to build at least 2 bikes.... one for cruising, one for fun. Remember, I'm the guy who had a Spitfire and a GT6 in the garage..... and 7 junked Spitfires in the back yard for parts. I figure if I can pick up 5 or 6 bikes I can build 2 out of the parts.... one for fun, one for bike trips with my dad....

[Ruah]

I used to ride one of the 1300 cruisers which are like the modern version of the fist pics (with the front hood) really great bike.  Classic owners complain about parts and eventually recommended I get a classic triumph instead.

but I moved.

[Maverick]

I have had 2 of the old airheads (750 and 1000) and I drove a beemer from 76 through 10. The old airheads are the last of the BMW's that the owner could expect to be able to fix using minor shop tools and mostly the supplied tool bag in the bike.

The main weakness is in four areas. The alternator is weak and has a hard time maintaining the battery that was arguably too small for the job anyhow. Almost all of us had a battery tender (1 amp) trickle charger to use on the bike to keep the battery at peak. It takes a lot of amps to run those big cylinders and get it to fire.

The second weakness was in the valve train. Most of the airheads were built before unleaded gas and the heads had to be redone with hardened valve seats. By now any bike that has been regularly driven already has them. The valves will still need to be adjusted every 1500 to 2000 miles. Too tight is much worse than a tad sloppy as you do not want to burn them. On the other hand pulling the head is pretty darn easy compared to anything else out there. Do NOT over rev the engine. It is easy if you miss a shift and crank on the throttle. You will bend a valve or two.

The ignition system (points and condenser) is subject to wear and timing issues. Most of us swapped it out for an electronic module and forgot about dressing the points and resetting the timing. In addition to that since you have 2 carbs on it you will need a set of mercury sticks (balancing kit) to make sure both carbs are set properly and the throttles are synced. It is simple once you have done it a few times. You can swap the original BMW coil for a blue coil from a VW supplier that will give a hotter spark. Worth the expense if the BMW coil is still good but cheaper than an OEM part.

The last weakness was in the brakes. They were not really up to dropping an anchor and minimum distance stops. If you have dual disks up front that helps a bunch. Check for steel braided lines to the front calipers. If the lines are still rubber, swap them for the steel braided lines to keep line expansion from stealing some of your brake power. If you have single disks there are mod kits out there to convert to dual disks. If you want to maintain the single disk expect longer stopping distances than you might otherwise be used to.

If you have bing carbs they are more reliable than the del orto's were. They didn't give as much power but they just kept going. They would occasionally blow a diaphragm but that is a simple and cheap fix.

Get BOTH a clymer and a Haines manual for the bike. You will find that they tend to complement each other and one often has better pix or explanations than the other one.

If you have a bad tranny it is better to send it away for a rebuild than do it yourself unless you are very very experianced with them and have all the special tools needed. It will cost more for the tools than the job is worth.

Parts are very available for even the old vintage models like the 500 cc single "thumper" so do not worry about not getting what you need.

Look into the tank for rust. If there is rust (common) the tank sealant has failed and you will need to have it redone or do it yourself. Put an inline fuel filter on both lines just above the carbs. Use a see through model so you can tell if it got crudded up.

Unlike the newer "oil heads" the drive line on the airheads is pretty bulletproof. Not much to do there but putting a bit of good high temp moly grease on the drive splines will help clutch movement and cut down wear.

Keep a spare set of cables on the bike for the clutch and throttle. Most of us wound them around the seat frame mounting point to keep them out of the way.

[SFRT - Frenchy]

Bought a clean 75 R900 3 years ago, $2K. Installed handlebar blinkers from early bmw, removed speedo, squeaking.

[Heater]

I have a 1200 GS and love it, 62000 km now and never had any problem with it...
granted it's not 100% air cooled but still a good bike