1956 R26 - My New Baby Has Some Issues

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Carott
Posts: 34
Joined: Tue Apr 14, 2015 9:18 am

1956 R26 - My New Baby Has Some Issues

Post by Carott »

At the end of August I was fortunate enough to acquire a 1956 R26.
$_59 (6).jpeg
BMW Archive sent me this information.

"The BMW R 26 VIN 348092 was manufactured on July 02nd, 1956 and delivered on November 23rd, 1956 to the BMW importer Phanich Company in Bangkok"

Unfortunately the bike does not have the original engine and the serial number stamped on the motor (6272358) is not related to an R26.

I have downloaded and printed out the factory repair manual and also purchased the Barrington Book/Bible.

So far I have changed the fluids, installed and balanced new tires, cleaned and polished the float needle and seat and fabricated an idle stop screw for the carburetor.

It starts easily and runs through all 4 gears as expected.

I will start my pleas for help in my next post.
20200916_152347_1.jpg
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Brett

Carott
Posts: 34
Joined: Tue Apr 14, 2015 9:18 am

Re: 1956 R26 - My New Baby Has Some Issues

Post by Carott »

My first issue is to work on solving the ignition/charging mysteries.

The bike was setup running off the battery with no operating charging system when I bought it.
My research showed the R26 having the coil mounted on the front of the engine but this bike has one under the tank.

Apparently you shouldn't read too much before working on a new project because nothing on the front of the engine looks like anything in the manuals or fiche.

Front cover.
20200916_145554_1.jpg
Advance mechanism with 13mm head on bolt.
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Points plate.
20200916_150518_1.jpg
Strange extension to the crankshaft held on by the advance mechanism bolt and indexed to the crankshaft.
20200916_151313_1.jpg
And the end of the crankshaft tapped for a M14 x 1.5 bolt (I am assuming this is for a puller to remove the rotor)
20200916_151326_1.jpg
I stopped at this point because I am unsure of how to proceed. I gently tapped on the body of the stator to see if it would come loose but it sounds quite solid.
Hopefully someone has seen this setup before and can advise me on how to proceed without destroying anything.
Failing that I may have to build a puller for the stator and then a M14 x 1.5 bolt drilled and tapped for an M8 rotor removal bolt to get the rotor off.

OR???

Maybe the rotor and stator are removed together somehow as I can't see how to access the brushes I would normally expect to find on the front.

OR???

Could it be a permanent magnet rotor.

Any and all suggestions would be appreciated.

Dazed and confused but still happy to own it,

Brett

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schrader7032
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Joined: Fri Oct 27, 2006 3:00 am

Re: 1956 R26 - My New Baby Has Some Issues

Post by schrader7032 »

Brett -

I don't know much about R26s and am not that versed on all of the various charging/ignition systems. At some point, I thought the singles did convert to a standard coil installed under the tank. My R25/2 has an older fashioned coil as part of the stuff under the cover. What voltage doe this system put out? Is it a 12v system? I'm guessing you're not seeing any stampings on this to give you some idea of who made it.

I don't think it's standard for BMWs, so it might be something for another manufacturer.
Kurt in S.A.
'78 R100/7 '69 R69S '52 R25/2

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San Arthur
Posts: 474
Joined: Sun Apr 22, 2007 2:08 pm

Re: 1956 R26 - My New Baby Has Some Issues

Post by San Arthur »

Carott I have to agree with Kurt, the set up on your R26 is not standard. Micro fish and manuals show coil behind the cover, not under the seat. Also the battery case looks similar to an R25. I've the same question as Kurt, is it a 12volt system conversion, the headlight bissell looks different?
Also it sims like you have a R27 exhaust pipe.
Can you send pictures about the ignition setup under the seat?
Thanks
San Arthur in San Antonio, Texas
'58 R26 '76 R90S '94 R100GS/PD

Carott
Posts: 34
Joined: Tue Apr 14, 2015 9:18 am

Re: 1956 R26 - My New Baby Has Some Issues

Post by Carott »

Kurt, San Arthur,

This is definitely a non-standard installation. The bike's wiring was stripped off the bike when I bought it so I have no way to determine if it is 6 or 12 volts. I was hoping to remove the generator (or alternator) and evaluate the condition of the parts to start rewiring the bike so it will charge.
20200917_175833~01.jpg
20200917_175833~01.jpg (19.71 KiB) Viewed 666 times
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Close inspection showed these marks on the stator and rotor.
The rotor is definitely a permanent magnet.
A quick internet search for K 609 alternator brought up a picture of the same logo and K 609 cast numbers on some guy's 1960's Yamaha YL-1. That would tell me that someone modified a Japanese system to fit on this BMW.
I have made a puller bolt for the rotor but I still need to determine how to remove the stator. Time to prowl the Yamaha forums for information.

The exhaust may well be from an R27. The exhaust spigot on the head has been crudely rewelded and the exhaust nut is a smooth but rusty steel ring with pipe wrench marks on it.

I'm sure there will be lots more interesting changes to deal with before I am done.

Brett

flr69s
Posts: 19
Joined: Wed Sep 23, 2015 8:50 am

Re: 1956 R26 - My New Baby Has Some Issues

Post by flr69s »

Hi Brett,
I suppose you also found out that the logo is from Hitachi?
Best regards,
Frank
Frank Louwers (Belgium) 1967 R69S

Carott
Posts: 34
Joined: Tue Apr 14, 2015 9:18 am

Re: 1956 R26 - My New Baby Has Some Issues

Post by Carott »

Frank,
I did find out that was the Hitachi symbol but thanks for helping out.

I finally got the stator and rotor removed from the engine.
Someone went to a lot of trouble to adapt the Hitachi permanent magnet alternator to fit the R26 engine and still use the stock points and advance mechanism.
Here are the parts;
20200921_191157~01.jpg
This does not look like the stock cover.
20200921_191222~01.jpg
I believe this is the stock advance mechanism and points, but I don't think the plate for the points is stock.
20200921_191233~01.jpg
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Here is the adapter which sits on the alternator rotor and has the advance mechanism attach to the front of it.
20200921_191449~01.jpg
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The alternator stator has six coils and three wires leading out from it.
20200921_191254~01.jpg
The permanent magnet rotor.
20200921_191305~01.jpg
And finally a shot of the front of the engine.
I am hopeful that there are no changes to the engine that would prevent me from returning to the stock generator
Brett

Carott
Posts: 34
Joined: Tue Apr 14, 2015 9:18 am

Re: 1956 R26 - My New Baby Has Some Issues

Post by Carott »

Here is the puller my friend made for me.
20200922_112727~01.jpg
It is an M14 x 1.5 bolt drilled and tapped to suit the standard BMW alternator puller bolt.
It worked perfectly.

Brett

Carott
Posts: 34
Joined: Tue Apr 14, 2015 9:18 am

Re: 1956 R26 - My New Baby Has Some Issues

Post by Carott »

The wiring for this bike came in a storage tote and I don't know how to proceed.
Long term I would like to return to the stock charging system but the budget says I need to try making do with what I have for now.
20200921_191853~01.jpg
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This appears to be some sort of a rectifier/regulator but I am unable to find any markings on it to confirm its function.
Any help identifying it would be greatly appreciated.
Also any suggestions on a suitable modern rectifier/regulator to use instead along with some guidance on how it might be wired in would do wonders on getting the bike closer to being a rideable beast.

Brett

Carott
Posts: 34
Joined: Tue Apr 14, 2015 9:18 am

Re: 1956 R26 - My New Baby Has Some Issues

Post by Carott »

Before I reassemble the Hitachi alternator and run the bike to determine what the output is I had another concern to deal with.
I had quickly checked the timing with a timing light and at idle it was rock steady on one mark and when I revved the engine it advanced to another mark and kept advancing past it.
I stopped increasing the RPMs to avoid damaging the engine.
The flywheel was very dirty and at the time I couldn't see any marks next to the lines.
My first thought was that the advance mechanism was faulty.
I cleaned off the edge of the flywheel through the timing hole as best I could and found the OT mark and confirmed it was at TDC.
The factory service manual calls to set the static timing at the S mark which is 7 degrees BTDC and full advance is at the F mark which is 42 degrees BTDC.
My bike has an extra mark between the S and the F marks.
I attached a degree wheel to the rotor while the stator was off and made a pointer out of wire.
20200923_170540_1.jpg
The S and F marks line up correctly with the degree wheel and the extra mark is at about 25 degrees BTDC.
I painted white marks on the OT, S and F marks and painted a red X over the extra mark.
The advance mechanism is well worn but does not appear to be damaged and the springs seem strong enough.
20200921_191222~01.jpg
I suspect that the PO had static timed the engine to the extra mark and that would explain the advancing past the F mark. It would also explain the occasional "two stroke-like" kickback when trying to start the bike.
Hopefully, careful reassembly of the ignition will show me more information when I get the bike running.
Brett

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