Thanks much!

The bloke with a beard in the sky, If your'e wondering what he looks like (and turn up the volume) since we're not even worthy of casting an optical nerve in the general direction of his supreme perfectness, this is what he looks like:

 

I will admit that I am not a mechanical engineer, . . .

NEXT!
 

BMW is by no means the only company using and recommending one-time stretch bolts in clutch assembly application. A likely reason to use them in production-line facilities is to be certain workers with differing skill levels, commitment, and weekend hangover recovery rate create an effectively tight assembly in the simplest way at one go. If one or more of those bolts loosen, shear force could break them.

No matter whether a stretch bolt is used once or reused, a non-stretch bolt is used and reused, or Loctite is being sprinkled like christening holy water on an assembly with the blessing of the local shaman, I think the main thing is to have an understanding of what is being done and be able to explain exactly why a personal choice is being made to do it a certain way beyond that guy (post, message from the mothership via dentalwork) told me it should be done.

After that, move on. Also, consider subscribing to AAA's rec vehicle/motorcycle long-distance towing policy.

Looking at the application, it appears to me that the tension load on these bolts is the clutch spring pressure and the result of the torque they are tightened to.  To me, the primary load appears to be shear resulting mainly from engine torque.  I will admit that I am not a mechanical engineer, so I am not familiar with the reasons for using a stretch bolt in a situation where shear is the main load on the fastener.  If I was designing the clutch, I would have specified a high strength fastener with a high shear strength and let it be reusable with Loctite.

P.S. Has anyone ever heard of a documented case where the clutch assembly has come apart due to the failure of these nearly $7ea($42 a set) fasteners?  Or is this another example of BMW's quirky and occasionally bizarre engineering and maintenance procedures? 

Hi all, short time lurker and first time poster. Thanks in advance for any responses

I recently acquired a 1990 K75 that I am trying to resolve an electrical issue with. The previous owner said the bike started to stall intermittently, but eventually would restart after a short time. Eventually the bike would crank but would not run. The PO replaced the fuel pump, but a new fuel pump didn't resolve his issue. This is the state I received the bike in.

I began troubleshooting by verifying the new fuel pump's operation. I supplied B+ and B- to the pump and it buzzed to life. The fuel pump fuse has voltage on both sides. I tested the tank fuel pump connecter and got the following results:

Key off test:
gr/wht wire- B+
yellow wire- B- (with some variance)
Brown- B-
White- B-

Key on test:
Gr/wht- B+
yellow- B- (with some variance)
Brown- B-
White- 1.0 volt

when cranking:
gr/wht: 0 volts (12 volts drops to 0)
Brown- B-

When back probing the green/white wire, while cranking, the pump buzzed to life. I was able to duplicate this by wiggling the probe. I then attempted to start the bike, and it purred to life. However, it would then slowly die, sort of like it was running out of fuel. I started it again and probed for voltage. As soon as the bike starts running the voltage drops to 0. As soon as it dies, the 12 volts return, and I can hear the pump buzzing. At this point I bypassed the connector and tested for 12 volts again while the bike ran. The voltage dropped to 0 when running and returned when it stalled.

So here are my questions:

Is the voltage drop on the green/white wire while running correct? or should I see 12 volts?

Am I correct in understanding the fuel pump should only receive voltage when the ECU sees a signal from the crank position sensor?

Am I going the wrong direction here?