R69 not running right

[Darryl.Richman]

You lot must be very brave if you ride these bikes out on the road without a rubber band over the key, I wouldn't, even if the switch and key were new, and stayed down, in fact the practice used to be so universal here that until I was about 14 I thought that was how it was intended to be!
It's not like I've put 100k on my R60/2, but I've never had a problem with the key not working correctly. I did have to bend the contacts slightly on my /3, but now I've put 6k miles on it and haven't had a problem.

Also, if you don't have the rubber band (cut from a 4.00 inner tube), what keeps water out of the switch? Here in the UK, and most other places where the authorities put salt on the roads in winter, your switch would rot away in one winter if you didn't keep it out.

That is a great "original, pristine" R60! What keeps the salt out of those vented front brakes?

[niall4473]

What keeps the salt out of those vented front brakes?

An old glove, only taken out in summer!

[EuroIron]

Here are two good examples, on this pristine, original, low-mileage R60.

very original and very pristine indeed

I'd also think such low mileage as to name it a trailer queen

nice!

aside from the stiffness afforded by the Zundapp's huge tubes, do you think those fork function better, hydraulically and otherwise, than the Zundapp forks?

the 4LS on my Fbed bike has two sets of "grill covers", one will allow airflow and the other is a dummy set that looks louvered

[niall4473]

aside from the stiffness afforded by the Zundapp's huge tubes, do you think those fork function better, hydraulically and otherwise, than the Zundapp forks?

I really don't know, having no personal experience of Zundapps which are almost unknown here, I take it you mean the KS601?
I do know that the BMW Earles forks are not as strong as they look, and failed the 'bus test miserably, hence the R67/2 front end on this bike. It handled very well, and contrary to your experience, I thought the front brake was OK.

[redavide]

I spoke to a mechanic here in Italy who's very well-respected and has a lot of experience with vintage BMWs -- after I explained the problem, the first thing he said was to check out the key just as you guys suggested. Tomorrow, I'm making a rubber band out of an old inner tube and it's coming with me on the next ride . . .

[EuroIron]

yeah the 601

it's tubes are over 40mm in diameter and they clamp in some really beautiful castings!

but it is hydraulically damped via an external shock that mounts from the top tree to the fender leaving the juice inside for lubrication purposes only

have I previously expressed displeasure with the BMW DLS front wheel?

best I can tell the half and full width hub brakes are fine although the half width doesn't have as much mass to dissipate heat

but much better than most bikes of the day had by a long shot

I think the tubes on the plunger fork fitted to that showroom fresh swing arm bike you have, are 35mm

not much used tubes that large until the Japanese invasion, save for a handful of WOP exotics

what do you guys make buses out of over there anyhow?

normally I'd apologize for such blatant thread jacking but it is reasonably dull around these parts

OP...good luck getting your bike running right

[Allan.Atherton]

... my '66 R60.... would suddenly start to sputter and miss a bit... The problem was in the key switch at the headlight, it would work its way up just the tiniest little bit (you can't see it) and the bike would "shut itsefl off" just for a second. I'd push down on the key and all would be well.... I never had this problem over several bikes and decades. It must be wear from withdrawing the key. I never withdraw my keys, merely pop them up to stop and push back down to go. And they are lightly greased so they work smoothly. But then my bikes are kept in a garage, and not parked in public during rides.

[redavide]

I'm fairly sure I found the problem, but I'll know for sure after I take a long enough test ride. The small rod that goes through the center of the float on the right carburetor was not the right one for my carb -- it had a small notch around the perimeter just above that little washer on the top of the float. The lever that pushes the needle up to stop the fuel (when the float is up) was getting stuck on that notch and keeping the fuel inlet closed.

To make matters worse, the needle was not seating right in the hole and was getting stuck quite tightly. I had to blow very hard through the top of the fuel inlet to dislodge it.

I've installed the correct rods in the floats -- they're smooth with no exposed notches. I also put in a new needle -- it's a little different -- seems to have a rubber tip but is the same size and all the new parts are moving smoothly and seem to be working perfectly. We'll see if that does it . . .

[VBMWMO]

I rode my R69 about 100 miles today. It ran perfectly except for three short periods, each one lasting about 5 minutes, when the engine started acting like it was running out of fuel, like it feels just before you have to go on reserve (but the tank was full). It sputtered, lost power and felt like it was starved for fuel. Then, after about 5 minutes, it started running perfectly again. I'm not sure whether the problem's related to fuel or ignition. Any opinions about what I should look at? Thanks.