1973 R75/5 Back-to-road Project

[anotherbmw]

Working on fork seals, steering bearings, bar end turn signals now.

Good advice on my leaking valve cover gasket! I went on a 20 mls ride, came back home and tightened the valve covers some more (probably above spec), but no more leaks!

I received the outer race bearing puller from CycleWorks in the mail (took 4 weeks, but was shipped after I sent a reminder). Tear down to replace fork seals and steering bearings started, I also drilled the inside of my handlebars so they can accept the bar end turn signals, inside diameter of the handle bars was only about 16 mm, which really surprised me given that outside diameter is 22 mm. Everything going smooth so far! I'll post some pics later (although there isn't really anything interesting to post I guess!).

 

[anotherbmw]

Everything is back together, fork seals changed, steering bearings changed, bar end turn signals installed.

The lower steering races had some good markings, feels much better now.

I have to finish the wiring for the turn signals and I need to find different bulbs/relay. I really don’t like the LED bulbs that came with the Hella kit. Does anyone know what wattage bulbs to use and where to get a matching flasher relay?

Also my neutral light now works sometimes, sometimes not, very annoying to say the least...haven’t looked into it yet, hopefully it’s not the switch which seems to be a pita to replace.

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[lmo1131]

Also my neutral light now works sometimes, sometimes not, very annoying to say the least...haven’t looked into it yet, hopefully it’s not the switch which seems to be a pita to replace.

The 4-speed switch is cake. The 5-speed switch is the PITA to replace. But neither one fails too often. Check the end of the wire that goes into the switch; it's easily damaged by over-tightening. Just clip off a bit, twist the strands together and re-install. If the wire is original it may have been "tinned" on the end.

On the 4-speed, the switch lives under a rubber cover (if it's still there). The set screw in the middle secures the wire, which feeds up through the hole from the bottom.

The 5-speed requires that the rear engine mount bolt, and the compression tube (between the engine mounting bosses), be removed to get to the switch.

 

[anotherbmw]

I guess I am glad I have the 4-speed tranny then

Thanks for the feedback, I'll keep this in mind, so far the light still works, but if the problem reoccurs I'll dig in there!

 

[anotherbmw]

Broke off the pin on the centerstand....

As the title says. I guess I was used to stepping on that massive pin from my R12000R, which makes putting the bike on the center stand so easy.

So here I am with a broken off pin and whenever I want to get my bike on the center stand now, I need to fiddle around underneath the exhaust to flip it down.

Can the pin be welded back on? New center stands seem to run $200 and used ones aren't cheap either.

 

[20774]

Can the pin be welded back on?

Yes, I think I've seen that discussed here on the forum, but don't know where. There's some consideration for removing the center stand for the welding or at least doing something to protect the bike's electronics by proper placement of the grounds for the welding rig.

 

[anotherbmw]

Reynolds stand

Thanks. What actually is the difference between a Reynolds stand and a regular stand? Any Pros or cons for either of those?

 

[20774]

This always results in a lot of opinions. The regular stand supports the bike on three points...two from the stand and the rear tire. The Reynolds also includes the front tire, so four points. It's easier to get the bike up on the Reynolds...should be less stress on the frame mounting points. The big issue people bring up is doing tire maintenance. You would need to put the feet of the Reynolds up on a 1x4 or 2x4 to get the tire of the ground. Could be an issue on the road but not so much in your garage.

 

[anotherbmw]

The big issue people bring up is doing tire maintenance. You would need to put the feet of the Reynolds up on a 1x4 or 2x4 to get the tire of the ground. Could be an issue on the road but not so much in your garage.

Thanks for the insight, I didn't know that.

 

[ebeeby]

Just weld the pin back on - like hundreds of other airhead owners. Oh, and step on the "mushroom" from now on.

You probably need to pull the center stand anyway to clean/grease the pivots. Easy job.

 

[anotherbmw]

Did the push rod seals on the left side yesterday. The piston looked great, however there was a large “spot” inside the cylinder, see photo. I couldn’t feel any roughness or anything it just looks different. Should I be concerned?

Oh and I will get that pin welded back on the center stand, thanks ebeeby!

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[ebeeby]

I would guess the bike sat for a while and that was the downward low spot where some moisture did its dirty work. If/when you change the rings, you can check the cylinders for roundness and ball hone the surface.

 

[anotherbmw]

I would guess the bike sat for a while and that was the downward low spot where some moisture did its dirty work. If/when you change the rings, you can check the cylinders for roundness and ball hone the surface.

That could be an explanation. Before I got the bike, it only got ridden about 5,000 mls in the previous 20 years. I still have good compression and it runs great, so I think I'll ride it for a while and see what happens. Thanks!

 

[anotherbmw]

Ready for some more fun! I will be tackling the main engine seal and everything on the way there. I did my shopping (I hope), Staburags fresh from Germany, a couple special tools (fly wheel puller, clutch tool, wrench extender for the driveshaft) and I hope I have all my parts lined up.

There are a few things I wanted to confirm before I get started:
I read that washers are no longer used with the drive shaft bolts, is that correct?
Is Staburags ok to use on the final spline as well?

Thanks anyone and wish me luck!

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[20774]

Right...shorter driveshaft bolts with no washers.

You're blocking the crankshaft so it doesn't move forward, right?

 

[anotherbmw]

I had ordered drive shaft bolts and washers, parts # 4-930-840 and 4-230-414. Should I use just the bolts then and leave the washers off?

Yes, I was going to block the crankshaft with a 2x4 piece of wood in the front as seen somewhere on the Interweb.

 

[20774]

No, you need the shorter bolts. The longer bolts were held in plate by the split washers...if you use the longer bolts, they may go in too far and contact the flange...plus you loose the locking feature. The shorter bolts are designed to stretch to hold them in place...technically, they are one-time-use-only. The washers (at least a few) were found to have broken, thus transferring load from one bolt to the others. If enough of the washers were to break, you have a real problem on your hands. Snowbum has info here:

http://bmwmotorcycletech.info/drvshftboltstoolstorque.htm

 

[anotherbmw]

No, you need the shorter bolts. The longer bolts were held in plate by the split washers...if you use the longer bolts, they may go in too far and contact the flange...plus you loose the locking feature. The shorter bolts are designed to stretch to hold them in place...technically, they are one-time-use-only. The washers (at least a few) were found to have broken, thus transferring load from one bolt to the others. If enough of the washers were to break, you have a real problem on your hands. Snowbum has info here:

http://bmwmotorcycletech.info/drvshftboltstoolstorque.htm

Dang, do I have to order the shorter bolts then? If so would you know the part number? Thanks!

 

[terham]

I just ordered four from boxer2valve for my '71. I think Northwoods Airheads has them and I'm sure many other places.

 

[ebeeby]

Bob's BMW has them and you don't need a part number