/5 Project: Re-attach the swingarm/shaft/boot

[AnnapolisAirhead]

Ok, so I am at the point where I am figuring out how to attach the swingarm and shaft and new boot.

It appears that the transmission end will be the harder part of the boot to install. I'm thinking I need to install the boot on the trans, then loosely attach the shaftbolts then loosely install the swingarm pivots.

I searched the forum for 'drive shaft boot replacement' but nothing, other than a thread on how to stop a leak. Any advice would be greatly appreciated, I'm headed to bed with Clymer's (a benign affliction that seems to help me sleep and wake with a new perspective).

 

[krehmkej]

Just did mine this week. With the swingarm loosened and slid back ( I had pulled the trans), I first fitted the boot to the swingarm. Do note that the boot is embossed Getriebe. Thus is the transmission end. Then I pulled the swingarm up and attached the universal. Finally pulled the boot around the tranny flange. I cheated here by using a Craftsman cotter pin puller tool (that I had smoothed off the pointy end so it didn't tear the boot) to ease the boot around the flange. All went pretty easy. The horror stories about this job that I hear seem to be when folks try to install it with the swingarm in place. IMHO, the little time it takes to R&R the swingarm pivot pins more than saves itself in frustration. As always, YMMV.

 

[sumran]

I used the same installation order and had no problems. It may be as easy the other way. I was bolting up to the tranny, so that side had to be loose.

 

[AnnapolisAirhead]

Just did mine this week. With the swingarm loosened and slid back ( I had pulled the trans), I first fitted the boot to the swingarm. Do note that the boot is embossed Getriebe. Thus is the transmission end. Then I pulled the swingarm up and attached the universal. Finally pulled the boot around the tranny flange. I cheated here by using a Craftsman cotter pin puller tool (that I had smoothed off the pointy end so it didn't tear the boot) to ease the boot around the flange. All went pretty easy. The horror stories about this job that I hear seem to be when folks try to install it with the swingarm in place. IMHO, the little time it takes to R&R the swingarm pivot pins more than saves itself in frustration. As always, YMMV.

I used the same installation order and had no problems. It may be as easy the other way. I was bolting up to the tranny, so that side had to be loose.

Great info, thanks. I don't have such a tool, but will figure something out to get the boot over the trans. That's a project for tonight.

 

[krehmkej]

That tool looks like a screwdriver with a 90-degree bend in the last inch. Very handy for lots of things it wasn't designed for. Any piece of rod with a bend and a smooth tip would do this job just as well.

 

[dennisdarrow]

A very small pair of hemostats or even needle nose pliers work well.........The important part is not tearing the boot. It is pretty tough though so with care it isnt really a problem. Get it over the lip, hold that point with your fingertips and work your way around. Really is pretty easy.

Do a bit of research about tighten up and the type of bolts for the driveshaft. LOTS of ideas about these MOST important fastners.

For the swing arm pivot nuts, I use a ground down around the edge 1 1/8 inch socket that just fits inside the lip of the swing arm. I believe that the torque is 72 pounds and this is really hard to do with the palm cutter that is in the tool kit.

Make sure you really check out about those drive shaft bolts. REALLY important to understand..........God bless..........Dennis

 

[bikerfish1100]

Do a bit of research about tighten up and the type of bolts for the driveshaft. LOTS of ideas about these MOST important fastners.

For the swing arm pivot nuts, I use a ground down around the edge 1 1/8 inch socket that just fits inside the lip of the swing arm. I believe that the torque is 72 pounds and this is really hard to do with the palm cutter that is in the tool kit.

Make sure you really check out about those drive shaft bolts. REALLY important to understand..........God bless..........Dennis

Dennis- why would you not use the correctly sized mm socket (either 30 or 32mm, don't recall which off the top of my head at the moment), ground down to fit inside the recess?

Those bolts are stretch bolts, designed for one time use only. The only question is "lock washer or no lock washer?", and that is determined by length of bolts. Loctite (blue?) is generally suggested in this application.

 

[20774]

Dennis- why would you not use the correctly sized mm socket (either 30 or 32mm, don't recall which off the top of my head at the moment), ground down to fit inside the recess?

Those bolts are stretch bolts, designed for one time use only. The only question is "lock washer or no lock washer?", and that is determined by length of bolts. Loctite (blue?) is generally suggested in this application.

There are two different bolts/nuts being discussed. One of the bolts Dennis was talking about was the swing arm pivot bolts. Those are 27mm and have a thin head. I have ground down the outside of a 27mm socket and also eliminated the lead-in taper in order to grab as much of the head as possible. Some find that a Sears 1-1/16" socket works as well...sometimes it fits within the recess without any grinding required on the outside of the socket. The tightening process is kind of weird. I believe it is 72 in-lbs (Dennis just said pounds...) initially but then is followed up with 15 in-lbs...or maybe it is the reverse. Anyway, there's a specific way to go about that. Plus you want the tube to be centered between the two sides of the frame.

The other bolts referred to attach the shaft to the output of the tranny, are smaller, and get something like 27-29 ft-lbs. Yes, they might stretch and maybe should be used only one time. But if they thread in fine by hand with no resistance, they're likely OK to reuse. If you have ready access to new parts, probably always the best. The early style bolts were about 14.5mm long with a lock washer. A bulletin recommended replacing with 13mm bolts and no lock washer. Some blue loctite would be good, IMO. I used my tool kit wrench, put a rag in my hand, and put as much force as I could while holding the rear foot brake. That should be plenty.

 

[AnnapolisAirhead]

Excellents tips, thanks guys.

I've been meaning to pick up a couple metric sockets and put them on the lathe (one for the fork nuts, one for the swingarm). No time like the present.

So, it looks like putting the boot on the shaft end first is the consensus.

I live too close to Bob's not to buy new bolts, hopefully they know about the 13mm recommendation Kurt mentioned and I'll use blue loktite.

Also, I'm toying with the idea of finding a LWB swingarm and subframe from an R75/5. It looks like it would bolt right up, provided I got one with the same gear ratio. Has anyone done this before? My thinking is that it goes further to reduce tank slappage and I could at least fit a normal sized battery tray in there.

With any luck, I'll have her back together this weekend, at least to a rolling chassis. I took one carb completely apart last night to clean. I prefer the CV types, but this bike came with type 53 sliders.

 

[krehmkej]

I have a 10mm double-box wrench that I found in a flea market years ago. Use this along with a big honkin 10mm allen wrench and really lean into them with the blue Loctite, too. That's always worked for me. FWIW, the only time I ever had a driveshaft fall off was on a brand new R80 back in 1988. Was the dealer ever embarrased on THAT one! That gets your attention real quick.

 

[James.A]

You can do the switch if you can get a swingarm with shaft and sub-frame and longer bolts and spacer tubes for the battery carrier. That's the only difference. No need to worry about gearing, you'll be using the same transmission and final drive. In fact, you can assemble the battery carrier in such a way as to be able to hold the larger battery typically found in a /6 or /7. However, the hold down straps will be way too short if you do this. I can show you how it is assembled in my 750 when the time comes, if desired.

 

[AnnapolisAirhead]

You can do the switch if you can get a swingarm with shaft and sub-frame and longer bolts and spacer tubes for the battery carrier. That's the only difference. No need to worry about gearing, you'll be using the same transmission and final drive. In fact, you can assemble the battery carrier in such a way as to be able to hold the larger battery typically found in a /6 or /7. The hold down straps will be way too short if you do this. I can show you how it is assembled in my 750 when the time comes, if desired.

Ok Jim, it sounds fairly straightforward and I am glad you've done it--now you are the expert. heh?.

I can deal with/fabricate a battery hold down, etc. However, since I (er, the bike ) currently has a short shaft, don't I have to worry about the splines on the end of the shaft that gear into the final drive? Are they all the same?

 

[James.A]

Not Quite

My bike, being a 1973, was always a LWB. I DID NOT convert it. However, I did change the battery carrier as described. The transmissions and final drives are identical between SWB and LWB. With respect to the drive line ONLY, the difference is the length of the swing arm, AND the driveshaft inside it.

 

[AnnapolisAirhead]

Ah, thanks for the clarity. You are still a pretty danged handy expert in my book. Good to know about the ratios. Probably oughtta just button her up and see how it runs and maybe look for a LWB swingarm and subframe later.

Thanks.

 

[James.A]

An interesting dichotomy

I figure that I own the first and the last of the LWB /5's. The first has a made-on date of 12-72, and the other has a made-on date of 8-73. By comparison, I once owned a 1974 R90/6 with a made-on date of 9-73.

 

[dennisdarrow]

Swing arm tools and Torque

Dennis- why would you not use the correctly sized mm socket (either 30 or 32mm, don't recall which off the top of my head at the moment), ground down to fit inside the recess?

Bikerfish

There once was a time when sockets in the metric range were not readily available, especially in rural N. America. In fact, when this tool was needed in 1973, the USA was argueing whether or not the country would join the rest of the world by standardizing tools and equipment in inches or metric standards. So, I did remove one of the nuts, went down to my local (now defunct) Oklahoma Tire and Supply and found what WOULD fit. Yes, and by coincidence it fit the size required perfectly. The socket has worked many times over the last 35 years and to this day, does not require replacement.

Kurt.................

Thanks for the correction about the appropriate size to use. I wrote my thoughts without double checking. Yes, the ol brain cells need a bit of double checking on before I run my mouth. 1 1/16th inch is totally correct.

For the torque values of the swing arm nuts, I refer to page 26 of the 1975 BMW owners manual when it guides how to tighten and adjust the swing arm pins. "tighten the lock nut (approx. 10mkp/72lb/ft)".
When I tighten the nuts I use my 24" ratcheting torque wrench set to the value of 72 foot pounds.

I believe that proper centering of the swing arm, adjustment and tightening of the pins, and periodic maintenance of these components not only effects, of course handling; but actually tire wear and gas mileage.

RIDE...............Dennis

 

[20774]

For the torque values of the swing arm nuts, I refer to page 26 of the 1975 BMW owners manual when it guides how to tighten and adjust the swing arm pins. "tighten the lock nut (approx. 10mkp/72lb/ft)".
When I tighten the nuts I use my 24" ratcheting torque wrench set to the value of 72 foot pounds.

Dennis -

I was also going by memory...you're right on the "ft-lbs" for the swingarm pivot nuts.

 

[bikerfish1100]

didn't realize you were working from a tool quite that old. my ground down metric, at about 25 years old, is just a yougster.
another useful matchup is 13mm = 1/2".