1973 R75/5 Restoration - Total Newbie

chris937 · Dec 10, 2019

Hi all, I inherited this BMW R75/5 from my late uncle Dave earlier this year. It hasn't been on the road since 1998 when one of the exhaust pipes literally fell out. Someone had picked the pipe up for scrap before my uncle doubled back for it in his Ranchero (which we V8 swapped and had a blast with as teenagers. But I digress...)

I had nudged my uncle Dave for years about buying this bike. He'd shoot me down every time. I just wish I could have acquired it under different circumstances. C'est la vie I suppose.

So why am I posting here?

I have very little information about this bike and I know even less about BMW's. About all I can tell you right now is that it's a 1973 BMW R75/5 with an aftermarket 2 into 1 exhaust.

The engine was turning over when I got it home 6 months ago. I hit the cylinders with fogging oil and cranked it enough to see it's not seized up. As of yesterday evening, the engine locked up while turning it over by hand. I'm hoping it's a valve/piston clearance issue but who knows until I open it up. Could even be a rust lip in the bore developed from sitting with an open exhaust port and valve for 20 years. (I sure hope not!)

Regardless, this bike needs everything. And it's going to get everything it needs eventually. I just don't know where to find parts, where to find information (service manuals, etc), and I certainly don't know what I don't know - LOL! Regarding this bike, that is A LOT.

I know for a fact that I have the following systems to address. Feel free to shout out a couple more I forgot!

Engine stuck
Fuel tank rusted
Carburetors
Tires & Tubes (replace)
Fuel & Vacuum lines (replace)
Brakes
L/S handlebar switch
Plugs, wires, nickels, dimes, etc, etc, etc...

PS Anyone local to the Dayton, Ohio area?

Here she is...

chunk · Dec 10, 2019

chris937 said:
Hi all, I inherited this BMW R75/5 from my late uncle Dave earlier this year. It hasn't been on the road since 1998 when one of the exhaust pipes literally fell out. Someone had picked the pipe up for scrap before my uncle doubled back for it in his Ranchero (which we V8 swapped and had a blast with as teenagers. But I digress...)

I had nudged my uncle Dave for years about buying this bike. He'd shoot me down every time. I just wish I could have acquired it under different circumstances. C'est la vie I suppose.

So why am I posting here?

I have very little information about this bike and I know even less about BMW's. About all I can tell you right now is that it's a 1973 BMW R75/5 with an aftermarket 2 into 1 exhaust.

The engine was turning over when I got it home 6 months ago. I hit the cylinders with fogging oil and cranked it enough to see it's not seized up. As of yesterday evening, the engine locked up while turning it over by hand. I'm hoping it's a valve/piston clearance issue but who knows until I open it up. Could even be a rust lip in the bore developed from sitting with an open exhaust port and valve for 20 years. (I sure hope not!)

Regardless, this bike needs everything. And it's going to get everything it needs eventually. I just don't know where to find parts, where to find information (service manuals, etc), and I certainly don't know what I don't know - LOL! Regarding this bike, that is A LOT.

I know for a fact that I have the following systems to address. Feel free to shout out a couple more I forgot!

Engine stuck
Fuel tank rusted
Carburetors
Tires & Tubes (replace)
Fuel & Vacuum lines (replace)
Brakes
L/S handlebar switch
Plugs, wires, nickels, dimes, etc, etc, etc...

PS Anyone local to the Dayton, Ohio area?

Here she is...

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Hi and welcome, you might say where you are located, maybe some local help. (Edited to ad: I see you say you're Dayton, missed it first read) Airhead guys and gals are the most helpful sort. As to the bike, it's a very desirable model and worth the effort. A total restoration may not be needed and if you retain the originality and patina it may be a better idea, many purist in the airhead crowd, me included. If it cranked freely 6 months ago, I can't believe it is very stuck. Looks like it was stored indoors at the uncles place? Not a lot of corrosion. I would free up the motor, do all the basic maintenance and see if it will run, probably will. Then I would throw that POS exhaust in the bin, find a proper bmw exhaust and ride it for awhile and then see if you want to do a full resto on it. That may well cost you more than the finished bike is worth, but if you have a sentimental attachment to it being in the family, that's fine. There's lots of technical info and help for airheads on the Internet and the bikes are incredibly simple, so you should be good to go. Keep us updated. cheers, chunk.

chris937 · Dec 10, 2019

chunk said:
Hi and welcome, you might say where you are located, maybe some local help. (Edited to ad: I see you say you're Dayton, missed it first read) Airhead guys and gals are the most helpful sort. As to the bike, it's a very desirable model and worth the effort. A total restoration may not be needed and if you retain the originality and patina it may be a better idea, many purist in the airhead crowd, me included. If it cranked freely 6 months ago, I can't believe it is very stuck. Looks like it was stored indoors at the uncles place? Not a lot of corrosion. I would free up the motor, do all the basic maintenance and see if it will run, probably will. Then I would throw that POS exhaust in the bin, find a proper bmw exhaust and ride it for awhile and then see if you want to do a full resto on it. That may well cost you more than the finished bike is worth, but if you have a sentimental attachment to it being in the family, that's fine. There's lots of technical info and help for airheads on the Internet and the bikes are incredibly simple, so you should be good to go. Keep us updated. cheers, chunk.

Thanks for the response chunk! I'm looking to restore any components or systems I need to so that the bike works like new (or something akin to new lol!).

I do not plan to paint over the patina, I think that'd be a shame. I guess my intent is more of a functional restoration like we did to my dad's old Yamaha a decade ago.

Dave was really proud of that vintage 2 into 1 exhaust (whose maker elludes me right now) so it will be retained if and only if I can find, build, or buy a replacement for the right hand side pipe.

Stuck is the only word I have. I was turning over it with my hand and then it just stopped. I put my body weight on it and it didn't budge one bit. I'd rather open it up for inspection than do any damage trying to force it over.

Yes, the bike was well kept in a garage in San Diego, California. It's been stored in my climate controlled garage in Fairborn, Ohio since late June.

Where's the best place to pick up a pdf or print service manual for these bikes? Thanks!

PS - my end goal (purely sentimental) is to get this and my dad's companion SR500E back to full glory while he's still with us.

chunk · Dec 10, 2019

chris937 said:
Thanks for the response chunk! I'm looking to restore any components or systems I need to so that the bike works like new (or something akin to new lol!).

I do not plan to paint over the patina, I think that'd be a shame. I guess my intent is more of a functional restoration like we did to my dad's old Yamaha a decade ago.

Dave was really proud of that vintage 2 into 1 exhaust (whose maker elludes me right now) so it will be retained if and only if I can find, build, or buy a replacement for the right hand side pipe.

Stuck is the only word I have. I was turning over it with my hand and then it just stopped. I put my body weight on it and it didn't budge one bit. I'd rather open it up for inspection than do any damage trying to force it over.

Yes, the bike was well kept in a garage in San Diego, California. It's been stored in my climate controlled garage in Fairborn, Ohio since late June.

Where's the best place to pick up a pdf or print service manual for these bikes? Thanks!

PS - my end goal (purely sentimental) is to get this and my dad's companion SR500E back to full glory while he's still with us.

Check ebay for a Clymer manual, and the Internet for info. Speaking of SR's. Mine i did a few years ago. I had to paint it as it was a mess when i got it.

Back to the BMW, it should be a reasonably affordable endeavor if you stick to what makes it safe and functional. It looks like it's in very good shape to start. Chunk.

ebeeby · Dec 10, 2019

A nice looking /5. I notice the front turn indicator lamps are missing - easy to replace.

Start by dropping the oil pan to see what is inside (sludge? Dry? Oil? Metal?)

Pull the plugs to help with trying to turn the engine.

You will need a good manual but best would be to have some experienced help. The best club for that model is the Airheads. More info here:

https://airheads.org/

Airheads are a bit, um quirky, and overzealous tightening of ANYTHING on them is a formula for disaster. You will need to know all the correct torque values and use them. Some manuals have them wrong (including BMW) - for example head studs/bolts are 25 ft/pds not 27 or 28.

Anyway, join the airheads and I'm sure there are some members not far from you.

anotherbmw · Jan 16, 2020

Looks like we have similar tastes! I just redid my toaster over the last 3 months, has also sat since 1998, but it it ran (kind of).

anotherbmw · Jan 16, 2020

and after....

khittner · Jan 16, 2020

That's a nice example of a /5, and generally well worth rehabilitating, particularly if it's got sentimental value. There were a number of 2-into-1 aftermarket exhaust systems back in the day, and I don't doubt that PO was proud of his---but his pride was probably misplaced. It doesn't have the telltale "Luftmeister" badgeon the muffler that typically adorned their offerings. It might be a Kerker, or whatever generic clone was being offered by J.C. Whitney. It's not likely to be particularly valuable. If PO rejetted the carbs to accommodate his "free-breathing" exhaust system, you'll need to sort that out during your carb rebuild.

k1200lt00 · Jan 16, 2020

I never dealt with them, but boxer2valve.com might be ably to help you out or the information you looking for.

bob_m · Jan 17, 2020

I believe the pipes are by Mac. Luftmiester had a similar set up (in black chrome) but the tip is flush with the megaphone in that set-up. Good luck with the project!

8ninety8 · Jan 17, 2020

Long wheelbase, 73 1/2, nice. Lot to like. Should clean up easy. Have a look into spark plug holes. If there was rust in cylinders, may have locked it up a little? Take yer time. Clean as you go. Youtube is yer friend. Lots of reading/learning to do. Euro bars. Koni shocks? Have fun, good luck.

1973 R75/5 Restoration - Total Newbie

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