1981 R100RS Diaphragm Spring Height

[kutter]

Continuing disassembly.
Does anyone know the height of the Diaphragm Spring (Relaxed)
My Clymers says 1981 - on 1000cc models NA
All other models 18.5-19.5mm
Diaphragm Spring measures 13.8mm ?
Friction plate minimum 4.5mm - Measures 4.8mm - Replace

[moosehead]

There are couple pics of replacement diaphram springs with measurements on the Motobins website...looks like 12-13.5mm? Check it out here. Might help. Part #60300 and 60305.

http://www.motobins.co.uk/bmw-parts.php ... lve%20Twin

[dougie]

I believe my '87 has the same spring.
At close to 100,000 km I decided to replace it and the friction disc while doing the rear main seal.
Don't remember the measurements, but I can tell you that the new spring was noticeably taller with both laying face down on the bench.
Now, barring disaster, I won't ever have to go in there again. And that was worth the price to me.

[kutter]

Sorry moosehead,
I was referring to the Clutch Diaphragm Spring.
Those part numbers refer to Bing CV diaphragm spring.
I was not explicit enough in my question.
I have ordered HD Clutch diaphragm spring 32025
from MotoBins.Will post dimension for future
reference on arrival.

[vanzen]

Hmmm, interesting.
My BMW service manual lists a relaxed length for the 79 R100 as 17.4 ±0.3 mm
but no specs for the 81 which is included in the manual ... and, given the (clutch / flywheel) changes,
I might suspect that the specs should be different !

[moosehead]

Sorry moosehead,
I was referring to the Clutch Diaphragm Spring.
Those part numbers refer to Bing CV diaphragm spring.
I was not explicit enough in my question.
I have ordered HD Clutch diaphragm spring 32025
from MotoBins.Will post dimension for future
reference on arrival.

I re-read your query and, dah, you do mention "friction plate"...my mind had a brain fart methinks...

[kutter]

A weeks wages worth of RS parts arrived from MotoBins this morning.
The Sachs heavy duty diaphragm spring is 14.6mm high, so the old
one has lost a slight amount of its push. Right Click and view image!




Also included were the carb rebuild kits so I soda blasted one carby to show the difference.
I then proceeded with the rebuild. The throttle needle in the air slide needs replacing
as it has a couple of wear marks on it. The rest of the internals are ok.
The carbys are 94/40/111 and 94/40/112. Not mentioned in my Clymers,
but 109/110 and 113/114 are.




SuperCheap Auto sand blasting gun ($50.00) , 90 lbs of air and 500g Bicarb Soda.
Now need to source larger amounts to do the rest of the engine etc.

[SteveD]

The carbys are 94/40/111 and 94/40/112.

R100S. Main jet is a 160, needle jet 2.66, needle on the third clip.
The size of the MJ varies from 160-165-170 amaongst the S, RS, RT.
The needle jet can be 2.64, 2.66, 2.68.
R100S has the 3rd position, R100RS is on the 2nd...all per Mr. BING's lovely book of stuff.

Bottom line is it probably doesn't matter too much, as these things are obviously variable. The book will list the original specs/settings, but after 30 years who knows what's happened as PO's have mixed and matched.

Soda blasting inside or outside?

[kutter]

I did the soda blasting outside Steve.
Our garage connects directly to the house.
I would be very popular if I blasted in there!
Yes the Clymers gives similar figures
for the R100RS (1981-1984)
but quotes the carbys as 94/40/113-114.
But we know Clymers has been wrong before.
For the previous driveshaft issue (With Clutch) Clymers
states was fitted to all monoshocks (except GS).
They state that all twinshock models had the hex nut on the FD end.
This was changed to the clutch type from 1979 on
including twinshocks.
Need to source larger quantities of soda now to clean up
the other grotty bits. Maybe chinese type food supplies store?

[SteveD]

Need to source larger quantities of soda now to clean up
the other grotty bits. Maybe chinese type food supplies store?

Do you have a local food co-op? The local bakery may buy bulk?

mail order? http://www.trumps.com.au