Part # 2121-90-100-to-80
Clutch Service Kit R90-R100 up to 1980

Clutch Service Kit R90-R100 up to 1980

Boxer2valve's clutch service kit contains all the parts you will need to replace the clutch components on your R90/6, R90 S, R100, R100/7, R100 RS and R100 RT up to 1980.

This kit includes the following:

Diaphragm Spring, Heavy Duty

This is the clutch Diaphragm spring that was used for the more powerful motors, starting with the R90 S and on through the R100 Models up to and including the 1980 model year.

Dimensionally, this is the same as the diaphragm spring used in the earlier, less powerful models, part number 2121288. This spring can be installed in any bike from /5 to 09/1980 production, the tension will however be greater and the lever pull much harder.

If you have installed a Siebenrock Power Kit on your R75 then we do suggest using this heavier spring. Also if the harder lever pull is not something that concerns you, in that case also opt for this spring.

Mark + Swiss Clutch Disk

This clutch disk features a highly reinforced construction, superior to the original. The hardened spline is attached to both the clutch disk and a steel reinforcement plate with 8 rivets and the reinforcement plate is attached to the disk with an additional 8 rivets, 16 in all, making this the strongest clutch that we have ever encountered. The organic lining has a special metallic compound that will offer many years of reliable service.

Important Note: When replacing your clutch, it's not enough to just replace the disk! It is a good idea to also replace the pressure plates and the diaphragm spring.

it's also important that your clutch cable is properly adjusted. This is important so that the clutch actuation mechanism has full movement. Failure to perform these tasks may result in premature failure, wasted effort and money.

Fits /5 /6 /7 models up to 9/1980

Comparable to 21 21 1 236 332

Compression ring for clutch

This part should always be replaced when installing a new clutch disk. Even if the old one "looks good", wear patterns have been established and the replacement disk will wear out prematurely if it's re-used.

Replaces BMW part number 21 21 1 231 666

This part may appear to be different than the one removed. If the original part has spacers between it and the pressure plate, those spacers are not re-used. This part has been machined to incorporate the spacers and they can therefore be discarded. Always use new bolts when installing this part.

Pressure Plate for clutch

This part should always be replaced when installing a new clutch disk. Even if the old one "looks good", wear patterns have been established and the replacement disk will wear out prematurely if it's re-used.

Replaces BMW Part Number 21 21 1 251 801

Always also replace the diaphragm spring, compression Ring and 6 bolts. Fits all models from /5 to 09/80 production except R45/65

Bolt for clutch disc

Replacing the clutch bolts every time the clutch is removed or replaced is the right thing to do.

These are the replacement bolts for all clutch assemblies from /5 through 09/80 production. 6 are required.