R27: the super-slow resto

[Renner]

'61 BMW R27
Manufactured on Februyr 21st
delivered on September 28th, 1961 to the BMW dealer Lindner in Blaichach.

Despite my good intention this project has been idly occupying my garage for far too long. I'd rather be riding it.

Maybe some computer time spent running this thread will provide a bit of incentive to keep the job rolling(?)

As is common these days, plenty of other projects promise to perpetuate a plodding progress.
The good news is I plan to post a plethora of pics.

[Renner]

Resources I've used so far listed here.

Shops
Craig Vechorik at Bench Mark Works, LLC...... http://www.benchmarkworks.com/
Dan Neiner at Cycleworks: ......................... http://www.cycleworks.net/
http://bore-tech.com/
http://www.ulismotorradladen.de
http://www.meyer-bikes.com
http://www.motorrad-stemler.de/index.htm

Clubs
http://bmwvmca.org/
http://vintagebmw.org/

Fora
http://autos.groups.yahoo.com/group/bmw-mono-club/

[Cordless]

Please post progress promptly. Public pleased as punch to peruse posthaste all pictures til that one plunger putts its ppb pb pb pb pb pb pb pb pb pb pb pb pb pb pb

CaPische?

[Renner]

"ppb pb pb pb pb pb pb pb pb pb pb pb pb pb pb" indeed


8 minutes into the thread and already I'm being schooled by a master

[Renner]

first bit of bling



gotta go now, not sure where I left the cam and generator.

[Bill Harris]

Following.

Needs a bunch of "before" pictures.

What is that bling in Post#5? Flywheel/clutch? It's lightened and balanced...

[Renner]

Sorry, no "before" pics, and only rumors regarding its past.
The basket case included the rolling frame and painted sheet metal plus a bunch of new & old parts.
Some parts duplicated, some not correct.

This is what I brought home.





Most everything appears to be ok.

I've since down the engine and transmission for inspection because I don't know where the previous owner(s) left off.
Nice cross-hatch on the cylinder walls. The bore averaged 2.6755 inches, slightly under spec so perhaps it was re-sleeved?
The piston looked new.
I sent both to Bore-Tech for their carbide bore and piston coating processes.



The assembled head also looks new. Probably I'll remove the valves and inspect seats, faces, spring rates, and valve shaft & guide dimensions to verify all is within spec. Also checking for leaks past the valves by pooling gas in the combustion side and seeing if any gets past the seats.

I removed the transmission cover but am waiting for bearings before I actually pull the gear shafts. No sign of rust.



I removed the crank and found the slinger clean. Dan at Cycleworks inspected the crank which checked good, he replaced the rod bushing.

Dan also lightened the flywheel as shown above.
Richard Sheckler recommend this for better acceleration off the line.
Bore-Tech shaved the cylinder top .040" for me at his recommendation as well.

I've worked a few of the smaller issues: rewired the left switch assembly, corrected both wheel bearing stacks, bought and installed some missing hardware etc.
...but like the bike, this project has been going nowhere fast.

On the + side: yesterday I finally managed to remove the aft cam bearing.



Eventually I'd like to commute on the bike. Work is less than 5 miles away.

[Kai Ju]

My first bike was a 1954 R25/3 that I bought when was still living in Germany, back in 1972. Bought it for the equivalent of about $15.00. Rebuilt it without restoring it, kinda wish I had brought it with me when I moved to the US.
Looking forward to watching yours come back to life.
That flywheel is a work of art. Almost a shame to hide it behind the clutch.
Looks great so far.

[Bill Harris]

But still, they are as before-ish as we'll get on this phase of the project. I've never seen the insides of a thumper before.

[Renner]

Originally Posted by Bill Harris

But still, they are as before-ish as we'll get on this phase of the project. I've never seen the insides of a thumper before.

Quite right.
though I don't have a handle on the bike's past, I've managed to accumulate a brief history with it.

#1 lump with the generator out



driven end of the oil pump shaft lives under a cover near the dipstick.
pushrods exit the upper pair of holes



coil ignition. these points weren't so good.



fitting the master link to this cam chain may be a breeze compared to the type 247 challenge



clutch on display



and a closer look.



Sprockets look serviceable.

Apparently I stopped taking pics during crank removal (what was I thinking).

[Renner]

Originally Posted by Kai Ju

My first bike was a 1954 R25/3 that I bought when was still living in Germany, back in 1972. Bought it for the equivalent of about $15.00. Rebuilt it without restoring it, kinda wish I had brought it with me when I moved to the US.

$15.00!
I'm wishing you'd brought it back to the US too.
Do you have photos you can share?

Mods vs. Rockers ride this Sunday in San Diego, hope you can make it.

[Kai Ju]

Originally Posted by Renner

$15.00!
I'm wishing you'd brought it back to the US too.
Do you have photos you can share?

Mods vs. Rockers ride this Sunday in San Diego, hope you can make it.

No, sure don't. I owned for about two years, 1 1/2 of which was before I got my drivers license. Luckily I never got caught.
The R25/3 was the 13 hp wonder. The bike would go faster in third, about 60mph, than in fourth.
Much to everybody's chagrin I'll describe the bike.
It was a Bobber before there was such a thing.
The frame was painted a very loud Ford green paired with a gloss black fuel tank, headlight shell, ears and forks.
Stainless fenders and a brand new stock exhaust. Solo tractor seat, no pillion.
My proudest moment came when I passed the TUV inspection on the first try.

I cut my teeth working on that bike at a friends Yamaha shop in my hometown. (Not to mention translating English language shop manuals to German)

In my defense, you have to remember that back in the 1970's these bikes were the proverbial 'dime a dozen'.
Hindsight is a beautiful thing, ain't it ?

I'm really looking forward to seeing yours when it's done.

[FreeTheBeast]

That's a nice bike! They don't make them like this anymore. You'll be so pleased to ride it once it's done.

[davorallyfan]

Originally Posted by FreeTheBeast

That's a nice bike! They don't make them like this anymore. You'll be so pleased to ride it once it's done.

Hmm have you ridden one? They are one of the most gutless bikes ever made.

Pretty yes... but effort and reward???

I dont mean to piss on your fireworks just letting you know.

[Bill Harris]

250cc, all of 13hp. Gutless, yes, but they have such charm...