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ogre
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Hello everyone,
I own a '39 BMW R51. Nothing matches in this bike but i bought it running few years ago and rode it without any problem.

Now i think its time to make it more original.
First thing i need is an engine case. Mine is r5 case 1936.
So if any of you got R51 engine case please contact me Smile.
Also need Amal carbs.

All the Best,

Jack

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Darryl.Richman
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Surf City, USA (Santa Cruz, CA)
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What a fun bike to have! I

What a fun bike to have! I am sure that if you advertise for a while, you'll find someone who needs an R5 engine case and will find you an R51 case. The carbs will be very hard to come by and very expensive, but depending on which Bings you have, you might get a good jump on the cost by selling them off.

What's the little box under the tank?

You can get repop roundels for your tank that look correct for the period. Also, it looks like you have a /2 headlight bucket; even a /3 bucket would look more correct. If you get a set of steel rims and lace them to your hubs, someone will want the high-lip aluminum rims, and if they're 18" rims for a /2, you'll probably find that the bike is slightly faster with the original 19" rims. The mufflers are the postwar "swallow tail" style, not the prewar "fish tail" (but the swallow tail mufflers don't bite at errant ankles).

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Bruce Frey
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Texas Hill Country, USA
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Engine Case Exchange

Hi Jack,

I got a spare R51 engine case when I purchased my R5 project. The number is 504723 and I would be interested in trading for the R5 case.

The only picture I have on this computer is attached. I am on the road right now and I won't be able to get any more until after Easter.

Cheers,

Bruce

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ogre
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BMW R51

Darryl.Richman wrote:

What a fun bike to have! I am sure that if you advertise for a while, you'll find someone who needs an R5 engine case and will find you an R51 case. The carbs will be very hard to come by and very expensive, but depending on which Bings you have, you might get a good jump on the cost by selling them off.

What's the little box under the tank?

You can get repop roundels for your tank that look correct for the period. Also, it looks like you have a /2 headlight bucket; even a /3 bucket would look more correct. If you get a set of steel rims and lace them to your hubs, someone will want the high-lip aluminum rims, and if they're 18" rims for a /2, you'll probably find that the bike is slightly faster with the original 19" rims. The mufflers are the postwar "swallow tail" style, not the prewar "fish tail" (but the swallow tail mufflers don't bite at errant ankles).

Hi, i got r51/3 bing on my R51. I know they are worth some money.
I read somewhere on this forum that R51 also have bing carbs at the end of the production, can you confirm this?

The headlight shell was zundapp hella headlamp, already sod to usa Smile
I was going to leave this alu rims as they are lighter than steel one. They are AKRON 19".
Mufflers and pipes already bought in Poland, look almost the same like orginal one Smile.

The box under the tank is electronic voltage regulator. Works very good just need to hide it somewhere.

Bruce Frey wrote:

Hi Jack,

I got a spare R51 engine case when I purchased my R5 project. The number is 504723 and I would be interested in trading for the R5 case.

The only picture I have on this computer is attached. I am on the road right now and I won't be able to get any more until after Easter.

Cheers,

Bruce

Hmmm, if its in good shape, not welded i will be interested in.
Tell me how much do you want for your engine case?

Thanks.

Jack

VintageSalesand...
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VBMWMO #7368
Corona, CA
Joined: 03/24/2008
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Other details

You also have the 1936 only - non-finned - generator cover. Any 1936 R5 owner that doesn't have one would love to buy / trade you for the correct finned one. The correct Amal Fischer carbs will be expensive - you should be able to get them from Martin - oldiedoc@t-online.de - I am rebuilding the drive train on a 1938 R51 now - such an awesome machine - love that motor.

Jeff

ogre
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r51 engine cover

Hi and thanks for that but i known this. Also front timing cover is from r5. Bmw r51 got mounting point to the frame on the top of this cover.
So what I need is engine case, top and front cover.

Hope the rest of the engine parts inside like camshafts and crankshaft are the same:)

Thanks for the amal cabs info will contact him asap.
Regards.
Jack

R68
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R5...

Did you know that the heads and cylinders are indexed to the case, and if you have original 1936 R5 heads, these are impossible to find? Very few would use a rare and valuable R5 motor as a donor to build up a somewhat less rare and less valuable R51 motor??? As for the generator cover, Josef Heft sells a fine repop, but the '37-'50 finned generator cover is functionally much better: much better generator cooling and the spark plug wires will not melt! Maybe you should contact Lesek in PL, get an M72 converted to R5 frame, and build up an R5 with your absolute unobtainium motor?

VintageSalesand...
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Front Cover

Ah! I did not know that the early R5's did not have an upper engine mount - neat! The heads are usually stamped with the engine number near the valve cover gasket surface - in the valley between 2 fins. What do yours say?

Curious minds want to know...

jeff

R68
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Front cover...

...getting very far out in the land of esoterica, but since you seem to be interested?...two pics showing a late '36 R5 in process of conversion to road race R5SS. Note absence of upper motor mount, placement of the bracket holding the extra plugs/plug removal tool that is really an upper motor mount, serial number on heads and cylinder foot, and very thin rocker support casting that's intact here, but usually rewelded after cracking on the R5. The R51 upper motor mount was added after they found that the case was cracking at the LHS rear motor mount bolt entry hole. To have a '36 R5 motor without such damage and with original unrepaired heads is unusual...also, AF carbs are basically for display, and Bings are less expensive, available, easier to restore?...I fear Jack is proposing take an R17 like motor to use as a donor to build a truck like R12?...

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ogre
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Hi, i ve checked the numbers

Hi, i ve checked the numbers and engine case is definitelly R5 1936, one of the first ever made and exactly number 3 Big Grin
Engine number 8003.
cylinders match this engine and also stamped 8003.
But cylinder heads gor same number as on reg. document so came of the original r51 engine.
So now it looks like i need whole engine, except heads Confused

Not sure what to do with that.
Maybe bulid up r5ss Smile
Regards.

Jack

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ogre
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Hi, i ve checked the numbers

Smile

stagewex
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Wow, number 3. Cool.

Wow, number 3. Cool.

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ogre
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Engine case

Hi, bought an engine case and got question regarding to OZ-80 stamp.
This was stamped on every case or from some time? On mine there is not one and the engine no. looks original.

Regards.
jack

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Darryl.Richman
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The OZ number - the fuel

The OZ number - the fuel octane that the engine needs - was in some way added to each vehicle the German army took to war. (OZ is Oktan Zahl, octane number in German.) On the R12, OZ-74 was cast into each head. For the plunger frame bikes, OZ-74 or OZ-80, depending on model, was stamped into the case on the upper left side. The OHV models wanted 80 octane, the sidevalves, 74.

If this case isn't stamped, then the bike it came from was originally a civilian bike.

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ogre
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The OZ number - the fuel

Thanks for your respond. It does have a sense as the engine case was bought it in uk and the bike was delivered here before second war.
Regards.
jack

R68
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Modified?

Has the rear motor mount hole been modified (moved forward) on that motor? On the photo, it seems much closer to the front motor mount hole!

ogre
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engine case

R68 wrote:

Has the rear motor mount hole been modified (moved forward) on that motor? On the photo, it seems much closer to the front motor mount hole!

just the illusion Tongue

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ogre
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EAS 170 HEADLAMP

Hi, got bosch eas170 headlamp but in poor condition.
Some one drilled bigger hols and welded original one.
Looking for glass now. Smile if any of you got one let me know.
Regards.
Jack

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ogre
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headlamp

Hi, i have finished headlamp. its prime painted

Also bought original ignition switch from Greece and bulb holder.
Now i need high beam switch and headlamp rim Confused

here is some pix.

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ogre
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headlamp

Hi, the headlamp almost finished.
The worst is speedo, nice repo but far away from original one Confused
Also not sure about key.I bought it as OEM one but not sure for 100% .
Any of you can tell me if its original bosch one?
jack

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Bigsieuk
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Shell

Very nice, no nice speedos in Mannheim then?

John

ogre
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Did not find any veigel there

Did not find any veigel there Confused i will keep this one for now. Maybe i will be lucky one day and find
original one Big Grin

Jack

ogre
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R51 cylinders

Hi, any of you got r51 engine cylinders for sale?
jack

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Interesting! I just checked

Interesting! I just checked my R-71 which came out of Germany and it was stamped OZ-74. My R-66 was sent to states and had no such stamping. Thanks!

Bruce Frey
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The lack of an OZ80 stamp on

The lack of an OZ80 stamp on your R66 would probably indicate that it was never under the jurisdiction of the German military.

Bruce

mdunn
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Jack, If you want to locate a

Jack,

If you want to locate a set of R51 heads try two things. First contact Josef Heft and next go on the moto club forum and post a message there in the BMW section. I have had incredible luck in this forum locating unobtainable parts trust me and I have been at this for a long time.

Mike

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ogre
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Tanks Mike, I needed

Tanks Mike,
I needed cylinders not heads but no longer, will have new ones Smile
My friend who is restoring gearbox and engine , he dismantled both for blasting.
Gearbox looks very good inside, just needs new bearings and seals.
Engine is a bigger problem but later about it Tongue

Jack

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R68
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Just out of curiosity...

...the motor your showing in you recent above post is not the same motor that was in your motorcycle when you first posted a photo of it back in March? This second(?) motor is R51?..Are you planning to use the timing chest cover with upper motor mount?

ogre
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Yes, the engine in my r51 is

Yes, the engine in my r51 is r5 motor. I bought engine case, timing cover and dynamo cover for r51. On r5 engine only heads match engine number on reg documents.
There will be also new cylinders with pistons.
Jack

ogre
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bmw r5 front cover

Hi, any one knows witch one of these covers are ealier model?
Both are R5 but the someone told the right one was for the first 100 BMW R5?

Regards.
Jack

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fernandez6246
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bmw r5 front cover

hi jack,let me know if you want to sale one of those timing covers?looking for one.
thanks.chris

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ogre
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bmw r5 front cover

fernandez6246 wrote:

hi jack,let me know if you want to sale one of those timing covers?looking for one.
thanks.chris

I might sell it or swap it for r5 parts if you got any.

I have finished engine and gearbox for my R51 and now it is the time for rest Smile

Jack

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fernandez6246
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bmw r5 front cover

hi jack,looks great.
could you send me you email address?
thanks,chris

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Hans
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r5 front cover

the cover on the right Side of the left picture is an early one. greetings

ogre
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r5 front cover

Hans wrote:

the cover on the right Side of the left picture is an early one. greetings

thanks Smile

So i can sell the left one.
Regards.
Jack

ogre
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R51 forks

Hi all, i removed the front end from frame.
Bottom legs are orginal, top yoke as well but there are no marks on bottom yoke?
Do you know what kind of mark or part no. should be there and were exactlly?
Regards.
Jack

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frankie1812
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Hello ogre I just looked at

Hello ogre

I just looked at the number 8003 on you cilinder and the first cylinders till number 8500 are different. They have long head bolts, and yours have the shorter one's. So looks like the number are not original.

Greetings Frank

frankie1812
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Here are some pictures

Here are some pictures

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frankie1812
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One more picture

One more picture

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ogre
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r5 cylinders

Hi,
The last pictures is from Lui post. I believe this cylinder for longer head stoods got number 89xx.
Will ask him.

Regards.
Jack

frankie1812
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No from 8000 till 8500

No from 8000 till 8500

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