R27 lack of power

[† Will]

Today I rode my R27 for only the second time. It does not have the power of my R25/3 (Lottie), where should I start looking for answers please?

Top speed is only 80kph. I can increase the engine speed without an increase in road speed. Otherwise it is a nice comfortable machine to ride.

[† Will]

[cledrera]

Hi Bill,
what`s about the clutch, the clutch cable and the adjustement of this parts?

Clemens

off topic
Once upon a time in garage in Kendall at night.
An bike named Lottie was not amused.
And so she says R27, my dear new nameless bike, listen:
No road speed over 80kph!
Look, this is a hammer ....

to be continued

[† Will]

Once upon a time in garage in Kendall at night.
An bike named Lottie was not amused.
And so she says R27, my dear new nameless bike, listen:
No road speed over 80kph!
Look, this is a hammer ....
to be continued

Hi Clemens,
Only a few days till we meet again, I will try your suggestion to start with.
And yes I think Lottie has made representations and like Queen victoria was "not amused".
Fond regards,
Bill

[rolf.soler]

80 ist km/h, not mph, right ? in that case far too slow. I had the same thing with my R27 when I bought it - it had a R26 piston, which ist about 5 mm lower, compression 5 bar instead of 8...
can you check compression ? or remove calve covers and head (possible without removing engine and tank) and check that.
Otherwise: carburetor problem; ignition timing, valve clearance.
increasing engine speed without accelereation an the road ? means clutch must be slipping...try to drive up a mountain (or something similar, haha...) in 3rd or 4th gear, if rpm rises but road speed slows, check clutch !

[Taz]

Hello Will.

Being able to rev up the engine without any gain in ground speed indeed hints to a clutch issue...had the same problem with Bärbel just days before our first Scotland trip-at that time I got oil from the gearbox on the clutch, resulting in a slipping clutch after a few miles...if it's the same right from the start I would think that the clutch system simply needs readjustment...

It might be a good move to reassure Lottie that it will be indeed her going to the continent in less than a fortnight from now on...in this case the nameless R27 might live

Keep my fingers crossed, Taz

[† Will]

The R27 is now named by Clemens as The Nameless One.
Today I checked the clutch cable free play and noticed that the cable routing was very restricted.
I think that the previous owner/'restorer' (huh?) has assembled the headlamp brackets on the wrong sides, so the clutch cable was very stiff.
I took the twist grip assembly apart to fit the correct parts supplied by the seller and the are badly worn and will not operate correctly.
I have stripped the carburettor down to check whether is correct and removed a small amount of water.
The air cleaner (engine number 380 533) does not have a filter fitted. Is this correct?
Thank you all for your interest and replies so far.
One day I hope to be able to ride this machine who at times in my garage is not so nameless perhaps.

[Kurt in S.A.]

Photos on this site show the headlight ears having the curved part on top:

http://www.bmbikes.co.uk/photopages/photosr27.htm

Kurt

[rolf.soler]

I think that the previous owner/'restorer' (huh?) has assembled the headlamp brackets on the wrong sides, so the clutch cable was very stiff.

Right, they're upside down...change right <->>left

I took the twist grip assembly apart to fit the correct parts supplied by the seller and the are badly worn and will not operate correctly.

on the photos you have two covers and two cogwheels. None of them work in any combination ? Try all 4 possible combinations. You can buy he cogwheel-chain assembly, however the coverplate ist difficult to find. Check also the teeth on the throttle tube !

The air cleaner (engine number 380 533) does not have a filter fitted. Is this correct?

What do you mean, no filter ? The R27 had a flat wire-mesh filter up to SN 379 581 (no change possible; cleaning and oiling needed every few 1000 km), from 379 582  the larger pillbox filter case with an exchangeable paper filter inside. Both are essential. Without filter the pas mixture is not correct. Post a photo of the air filter box so we can advise you what to do

P.S. the rubber seal under tachometer ist bad, replace or expect water in the headlamp when bike is parked outside or driving in rain

[Dappsull]

Nothing to do with speed and clutch, but the carriers for your headlamp are indeed assembled upside down

[† Will]

Nothing to do with speed and clutch, but the carriers for your headlamp are indeed assembled upside down

Thank you Dappsull, Rolf.Soler and Kurt S.A for your replies.
I have the English version of the BMW R27 Owners Instruction Manual and the photos on pages 1, 2 and the diagram on page 24 confirm your comments. Each time I work on this machine it's a leap into the unknown correcting the 'restoration' by the previous owner.

[Taz]

Hello Will.

Ouch...not  , but  ... so more satisfying and less painful for yourself 

Best regards, Taz l(ooking forward to meeting you at the Edersee)

[† Will]

What do you mean, no filter ? The R27 had a flat wire-mesh filter up to SN 379 581 (no change possible; cleaning and oiling needed every few 1000 km), from 379 582  the larger pillbox filter case with an exchangeable paper filter inside. Both are essential. Without filter the pas mixture is not correct. Post a photo of the air filter box so we can advise you what to do

Thank you Rolf, I have pasted pictures of the air filter below. The engine number is 380533.







This morning I will change the headlamp ears and check the throttle tube. I have a single  cable cover plate. I also note your keen observation about the rubber seal under the tacho head, I have a spare seal and will change it.
Many thanks again.

[† Will]

Just a thought!

Where would we/I be without the wonders of digital cameras, this forum and helpful friends?

[Dappsull]

Without digital cameras, form, and friends your R27 would look the way it looks now ;^).
Anyway: obviously oil-filter, so if Rolf's numbering system is valid, it doesn't match your engine number. Does engine number match to frame#?

Cheers
D.

[† Will]

Without digital cameras, form, and friends your R27 would look the way it looks now ;^).

Hi Dappsull,
This is how The Nameless One looks today.


Home but not alone!



Headlamp brackets being changed.

The engine, frame numbers match, as verified by Andreas Harz and BMW archives. Whether the rest of the components match is a just a guess. It may be a talking point at the Lake next week.
Cheers, Bill.

[Dappsull]

Wow - looks much better than mine, congrats!

[rolf.soler]

Thank you Rolf, I have pasted pictures of the air filter below. The engine number is 380533.

This is the metal-mesh oiled air filter; older type, according to the comparison list up to SN 379581 (?). In my opinion the better type, or at least more beautiful. It filters probably less dust, however dust is not so much of a problem today as it was in the 50's and 60's. Unlike the big fat filter, it doesn't need paper filters that need to be replaced regularly and cost money; just clean it every few 1000 km in a mixture of 4-5 parts gasoline and 1 part engine oil until liquid is clear, the let it dry. Dust sticks to the oily surfaces of the mesh.

[† Norrie]

Hi Will

I remember seeing pictures of 'The Nameless One' when first acquired and she is beautiful! 
I am confident that you will sort out her minor foibles, if not in time for your continental trip for the latter part of the summer, and that you will enjoy trips out with her to such an extent that you will want to give her a more ladylike name e.g 'Dagomar' (Glorious day) or 'Winola' (Gracious friend).

I look forward to seeing posted photographs of your trip and please give best wishes from Scotland to all participants. I will join you on my, as yet, nameless machine one day.

Kind Regards and 

Norrie     

[† Will]

Hi Will
I remember seeing pictures of 'The Nameless One' when first acquired and she is beautiful! 
I am confident that you will ---------------------------------- want to give her a more ladylike name e.g 'Dagomar' (Glorious day) or 'Winola' (Gracious friend).  

Hi Norrie, nice to hear from you and thank you for your comments.
If she gets a new title it could be The Olympic Flame which is something else that never goes out!
The headlamp ears are now on the correct sides which gives more clearance for the cables.
The clutch cable has been adjusted and the carburettor stripped down. I found some water and sediments in the jug used to catch the fuel when I disconnected the carburettor, so the tank will be drained completely.
The main jet is 120 not 125 as on the specifications the other jets are correct sizes.
The throttle return spring is very long at 94mm compared with the spring on the R25/3 which is only 67mm long. The depth of the recess in the slide is only 30mm causing the spring to not fully compress.


With the adjuster on the carburettor top screwed right out and the twist grip fully opened the throttle slide does not clear the intake as in the photo.


Throttle cable free length is 90mm.

[† Will]

Still no nearer to resolving the carburettor cable/throttle slide problem.
With the threaded adjuster screwed fully out the slide does not clear the intake aperture on maximum twist grip opening as in the photo below in my other post. A new non BMW cable was 'fitted' by the previous owner.

Can anyone tell me please if the free play on the cable is too long at 94mm?
The nipples are soldered at each end so I could easily shorten the inner Bowden cable if necessary.

[rolf.soler]

The spring length doesn't matter as long as it does not kink
The fault with not fully opening intake diameter is clearly with the cable. The inner wire is too long compared to the sheath. Again, total length does not matter, the length of free wire (difference sheath/wire length) is important. Buying a new complete cable probably does not help; these cables are always wrong, too short or too long...
Shorten the inner part (wire). Measure the length of free wire. Remove nipple on one side with blowtorch, push it back 1 cm, solder it back. You may have to shorten the sheath too, wire is probably not good anymore at the end. Cut frayed end of wire, solder nipple on good part of wire with 1 cm less free length as it had before. Fine adjustment with adjusting screw.

[† Will]

The spring length doesn't matter as long as it does not kink
The fault with not fully opening intake diameter is clearly with the cable. The inner wire is too long compared to the sheath. Again, total length does not matter, the length of free wire (difference sheath/wire length) is important. Buying a new complete cable probably does not help; these cables are always wrong, too short or too long...
Shorten the inner part (wire). Measure the length of free wire. Remove nipple on one side with blowtorch, push it back 1 cm, solder it back. You may have to shorten the sheath too, wire is probably not good anymore at the end. Cut frayed end of wire, solder nipple on good part of wire with 1 cm less free length as it had before. Fine adjustment with adjusting screw.

Thank you Rolf for your kind assistance.
The cable that was fitted to the machine was made from stainless steel wire with crimped on nipples which stopped me from shortening the inner wire.

I had a length of steel Bowden cable and I made some nipples from a length of brass welding rod. I now have a cable which should fit.
Below is a picture of the completed cable, the piece of brass welding rod and 2 spare nipples. I calculated the free length as 75mm, it's fingers crossed time again!

[† Will]

Reflections! The inner cable for the carburettor would have been an easier fit at 80mm free play not 75mm which is a a bit too short.

So tonight I took the R27 for a short testing run, plenty of power and pulling easily up to 100kph. 

After 10kms I slowed down to turn round for home and heard loud screeching noises from the front of the engine with the red warning light indicating not charging and a strong smell of burning.

A slow return home and the machine is confined to the workbench once again and will not travel to the Lake.

[rolf.soler]

sh...t   
sounds (or smells) of generator problem...

[Taz]

Hello Will.

See...Lottie is the queen of your garage and she has won the ride to Germany...well deserved IMHO as she was the one who rode with us all over the Grampian Mountains back in 2011...Bärbel got very excited to meet her again.

Good luck with the nameless one (maybe a name would help the machine to get rid of the bad karma)...and looking forward to seeing you at the lake, Taz

[† Will]

Hello Will.
Good luck with the nameless one (maybe a name would help the machine to get rid of the bad karma)...and looking forward to seeing you at the lake, Taz

Hi Taz,
We are nearly ready, plenty of tools packed, headache pills and beers. The nameless one is like the Olympic flame - it doesn't go out! Perhaps I should name it Jinx ?
Looking forward to the rally and meeting up with you and the rest of my friends for a beer or two.
Kind regards.

[† Will]

Hello again to all members,
Today I had a look at my 'Fully Restored' R27 purchased last September. You may remember that I made a new throttle cable and fitted it before going on a test ride prior to Edersee.
The machine ran a lot faster then started making a screaming noise then stopped charging. I coasted slowly home and put the machine back in its usual place on the workbench.
I removed the front cover from the generator and a lot of debris fell out. The damage is very obvious to see in the video now published on YouTube.
Where to go from here?

[Dappsull]

Outch, my condolences....
did the bolt only come off or has the thread in the crankshaft said good bye for good?

Cheerio

[cledrera]

Sh....

Where to go from here?

gun room 

[kruemel]

Will, you should rethink the hammer option... So at least, you will need a new alternator, but first take the lima away and look for the stator coils...

You will make it anyhow...