10 worst defects in '51-'69 twin BMW?

[R68]

1. Centerstand: Maybe OK for a single, too weak for a twin, wears, and no way to lubricate. Especially poor design of the mounting tang on the pre '60 twins.
2. Bosch headlamp switch plate: mounts with bend-over tabs, these may crack, hard-to-repair.
3. Throttle: ugly on the swingarm models, too delicate on the plungers, not especially responsive on either.
4. Rear view mirror hole on later twins: left hand thread in pot metal clutch casting that uses steel mirror stem, wears quickly.
5. "Sport" gas tank that leaks through the toolbox lock hole: rusts out the rear of toolbox compartment on a neglected bike left outside.
6.R69S steering damper: almost never functional?
7.Pre '67 tachometer drive unit: auto self-destructs.
8."USA" dual seat: for Americans who eat too much?
9. "Enduro" panniers: admittedly a controversial one here (?), but maybe really for folks who want to make their BMW into a Vespa scooter? "Buco" bags for folks who can't afford Enduros?
10.Big tanks, especially Fuhrmann series Heinrichs and oversized Hoske, unless on a sidecar motorcycle: reason BMW handle well is low center of gravity, and the HUGE tanks negate that?
11. Deletion of carb pre heat conduit in about '64: which is why the coils deteriorate/short out?
12. R68: too much motor for the obsolete rear suspension and especially the early half hub brakes in '52.
13. BMW stock side stand, especially the early non self retracting type: how to die early.
14. Everbest petcock after '55 production year: not really rebuildable, basically garbage; find a pre '55, or use a Karcoma?
15. Female (frame) sidecar plug: poor ground.
16. Steib hydraulic brake: probably only theoretical in function, but I'm not sure.

[niall4473]

I would agree with most of those, however I do not feel that BMW can be blamed for No.9 or No.16, No.3 a bit unjustified when the bikes were mostly either fleet bikes or tourers, the USA being an exception, sports twist-grips were always available on the aftermarket.
I would add:-
17, the totally unnecessary, mechanically ludicrous and sometimes downright dangerous method of actuating the rear brake on Earles fork bikes.
18. Not having any sacrificial bushes on the brake cam holes like even the cheapest, nastiest British bikes had.
19. Dropping the beautifully made R69 and replacing it with the R69S, a bike which has next to no torque and will snap its crankshaft at 5000 rpm if not fitted with a much misunderstood torsion damper.
20. Exhaust valves on the R60 which are highly susceptible to the heads dropping off.
21 Using 1/2" reach plugs in aluminium heads.
22 Driving the speedometer off the gearbox so that changing the gearing is much more more expensive than it needs to be on a bike that was heavily marketed as a sidecar puller, when there is nothing at all on the non-drive side of the rear wheel.
23. Using the front engine bolt for mounting the sidecar, so that you have to take the chair off to get the engine out.
24. Using the chassis to earth the wiring instead of spending a couple of pfennigs to run a wire from the headlamp to the battery.
25. Going back to the transverse acting kick-start after WW2.
26. Replacing the 1954 full hub wheel and front brake with the 1955 version which was never as good, despite re-designing the hub twice.
27. The oil system on the 1951-69 bikes which relies on people checking a sludge trap which is unbelievably hard to do, although TBF to BMW this is true on a lot of 1950s bikes.

[Flx48]

Ah- a little game of "With the Benefit of Hindsight!"

Ok, sounds like fun, here's my "Two Minutes to Name Ten", let's see-
An Earles fork with the brake plate anchored to the swingarm instead of to the fork legs (like in Ernie's original design, or say, how Douglas utilized the Earles on the Dragonfly)
An ignition actuated by a golf tee instead of a proper lockable key.
Or no 12 volt lights (except for those 1%ers) (even my '48 RV has 12 volts lights..) 
And no fuses?
How about those loose balls in the steering head, instead of roller bearings? (they knew enough to utilize them in the swingarms and wheels)
Or the cylinder heads made of Play-Doh (sure, they were regulated by save the planet, but a little bit of R&D..)
Carbs with flexible mounting flanges?
Riveted instead of glued brake linings?
5 color choices instead of 50?
Mufflers that rotted out when shown pictures of rain?

I dunno, I've loved riding them for over 50 years.
Even though I've got newer rides, they're still my go to bikes.
Kinda like a partner in a marriage, the shortcomings are right there to see; you either accept them warts and all, or you move along. 
Best-George

[jwonder]

I honestly see everything listed above as a reason to own these wonderful motorcycles.

I will disagree though with the original #12. The power of the R 68 allows me to control the rear much better than my R 51/3 and I can plant the rear in the middle of the corner with some power, but I guess it depends on the springs you have in the rear.

Oh, and my R 69 S and R 50 S steering dampers work great!! You just need to set them up correctly and maintain them properly.

Oh, and I rebuild the Everbest petcocks all the time as well, you just need to be careful with bending the body (with a bit of heat) to get it apart and learn to bend them back. They are really quite simple.

[808Airhead]

I think the plunger gearboxes shift much better than the Earls ones. Nobody mentioned the terrible position of the points for access to service, or the random,intermittent, varying degrees of tapping noises that seem to come and go randomly while riding,with no rhyme or reason.

[Tinkertimejeff]

Might be unpopular but I would put one defect in the top ten (position undetermined) a defect as new owners of a motorcycle designed 70 -80 years ago years ago, nursed through 25 plus years of production that kept the brand alive all with very limited resources for research and development. Some owners tend to buy a /2 at a premium without the understanding that the bike is prehistoric, needs attention and is not a 2014 Honda. They leak, clunk, swerve, stall, handle like crap and do all sorts of weird things. IT IS THE NATURE OF THE BEAST THAT IS 60 YEARS OLD!

To many current owners of vintage BMW's and other brands buy a supposed restored or original bike and think its a kick and go, take it in for an occasional oil change, my wrench will fix it when crap brakes and when it brakes they blame the brand or year. Many things about my 12 plus '55 - '69 BMW's rattle my cage at times but in a good way. I would never consider them "defects" or issues instead just the nature of the beast and you learn to look for those issues in other bikes. Know you bike, check it often, learn to work on it and don't rely on a shop to do the work you should do.

My 1961 R 50S has the original mufflers it was delivered with new, you just need to know how to take care of stuff.

[R68]

Gee Whizz, I learned of a lot of new "defects" from you guys I never knew existed when I made my post! All in all though, there's no other old motorcycle I know of that I'd rather have than an old BMW!!!

[Daves79x]

Just one addition - carbs that by design, leak.

Dave

[CWRoady]

Non vented Final Drive tops my list

[xackley]

Sorry to hear, you guys must have caught the lemons. My R69 has been the best riding, most reliable motorcycle, ever born.
From the New Jersey Turnpike to scrambling through the woods.

The only thing that ever bothered me was the rear tire wear profile. It's like the motorcycle would prefer a car tire back there and modifies the mc tire to it's liking.
So I guess it really isn't perfection.

Don