My R27 is now on the road

[SteveMKentucky]

I started a thread some time ago to document the restoration of my bike.   There seemed to be very little interest in the thread so I stopped posting.  Nonetheless, it's now completed and I've taken it on five or six half-day runs.  There were a few small issues to sort out but she seems to be running great for now:

[SteveMKentucky]

[SteveMKentucky]

I started a thread some time ago to document the restoration of my bike.   There seemed to be very little interest in the thread so I stopped posting.  Nonetheless, it's now completed and I've taken it on five or six half-day runs.  There were a few small issues to sort out but she seems to be running great for now:

Moderator, bitte löschen Sie den zweiten Beitrag.

[grahamjb]

Nice looking restoration

[OldsCool!]

Hey Steve,
nice one! How does she ride? R27s get rare, keep an eye on it 

best regards,

Steffen

[27-steib]

looks great- well done and enjoy.

The side Stand is not scraching the road in left bands?

Best regards Jan

[bwprice100]

Very nice Steve.

Brian

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[rolf]

Attention...your sidestand is a killer!....is has to disappear under the exchaust

[4Taktix]

-> Suicide-Kickstand !   

[RolfD]

nice Bike.... 

[SteveMKentucky]

Attention...your sidestand is a killer!....is has to disappear under the exchaust

Yes, I know.  The sidestand tends to catch on the header clamp.  I always make sure it's fully up before riding. 

I had just had it on the sidestand and put it on the centerstand for the picture.  I didn't notice that it was not fully up until after the pictures were taken.

[SteveMKentucky]

Hey Steve,
nice one! How does she ride? R27s get rare, keep an eye on it 

best regards,

Steffen

It rides great Steffen.  I must say it's very different from my larger bikes.  Each gear has to be wound up quite well before shifting into the next.  But it is great fun to ride.

[rolf]

Try to get a 27/6 instead of the 25/6 transmission.....it´s a new motorcycle with that transmission. in Germany it is called "Behördenübersetzung" because the cycle for police, army etc has that transmission

[SteveMKentucky]

Try to get a 27/6 instead of the 25/6 transmission.....it´s a new motorcycle with that transmission. in Germany it is called "Behördenübersetzung" because the cycle for police, army etc has that transmission

Thanks for the tip Rolf.  Not sure where I'd find one but will begin looking.

By the way Rolf, do you know if it's possible to replace individual gears within the gearbox to duplicate those in the "27/6" gearbox?  If so, do you know the ratios?

[rolf]

Yes...I think it`s possible....you can take gears from the twin gearboxes....for the ratios i am too lazy to calculate....changing the rear transmission is simpler to do. R27 from (roundabot) 65 has the "new" transmission

[bwprice100]

I have a friend, Brian Thomas, who has an R27 and I'm sure he put the internals from an R69S gearbox into his R27.
I think he changed the carby for one from a pre 69 500 twin as well.
It might be worth speaking to him.

Brian

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[rolf]

Brian,
that is not the question (I hope )....the internals are interchangeable...but what ratios you will take?

[bwprice100]

Brian,
that is not the question (I hope )....the internals are interchangeable...but what ratios you will take?

Hi Rolf

He did it to get better ratios but not sure of the differences though.

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[SteveMKentucky]

Yes, I've heard about using /2 gears.  I'm just curious what the ratios that Rolf mentions are.  I'll do some research and see if I can find the specs. 

I'm aware of the carb mod too.  I actually have one.  The carb is from an R50/5.  I found a couple of problems with the carb conversion.  First was fabricating a choke lever as the original uses a cable system.  The second is that the rubber bellows from the carb mouth to the airbag doesn't fit.   Fact is, my stock carb runs pretty well.  However, the /5 carb does have a better fuel bowl arrangement and it reportedly has a better idle circuit.

[berndr253]

Changing individual gears is not possible.
The secondary shaft is casted - so only one gear can be changed and that is the second gear of the "gear-triple".

Of course you can change the "set" of the gears from the twins (up to R29S R69S) into the housing of your R27. The first three gears then will be "longer" the 4th gear has the same transmission-ratio.
If you want to realize a shorter transmission-ratio you should have look for the "behördenübersetzung".
Hope everything is understandable and it helps
Regards

Bernd

[SteveMKentucky]

Changing individual gears is not possible.
The secondary shaft is casted - so only one gear can be changed and that is the second gear of the "gear-triple".

Of course you can change the "set" of the gears from the twins (up to R29S) into the housing of your R27. The first three gears then will be "longer" the 4th gear has the same transmission-ratio.
If you want to realize a shorter transmission-ratio you should have look for the "behördenübersetzung".
Hope everything is understandable and it helps
Regards

Bernd

Yes, thank you Bernd.   

The following link is to a thread on the Vintage BMW site that discusses (among other things) installation of a /2 gearset. The author also discusses using a 27/6 final drive ratio.  Please let me know if you can't see the thread without logging in.  The gearbox discussion starts at post #17:

http://www.vintagebmw.org/v7/node/7381

[berndr253]

No doubt, that it is possible to modify the gears by changing the shafts including the gears.
But have look onto what you want! If you wish a shorter transmission ratio use the shorter final drive - if you want "longer" ratios use the /2 gearset.
Mixing both may be interesting - one can calculate what happens in that case
Regards
Bernd

[grahamjb]

SALIS has some documentation on changing the gearbox ratios:

https://www.bmwclassicmotorcycles.com/parts/technical-tips/transmission-upgraderebuild-to-s-gearbox-ratios/

[SteveMKentucky]

SALIS has some documentation on changing the gearbox ratios:

https://www.bmwclassicmotorcycles.com/parts/technical-tips/transmission-upgraderebuild-to-s-gearbox-ratios/

Excellent info. Thanks!

[klawo]

Steve,

well done

Very, very good!!!

Klaus