Das Bike Projekt: How to Build a Better Clutch

So from our previous entry, we saw that the stock R75/5 clutch components were not up to the power of the hopped up, high compression, hot cammed Reg Pridmore engine.

How to get a clutch designed to deal with more grunt? Not as hard as one might think.

The stock 1973 engine put out 50HP and 44 ft lb of Torque. But using the same block, in 1973 to 1976 BMW built the sporty R90S with 67HP and 56 ft lb of Torque. After doing some research, I found that BMW designed a heavy duty clutch, which is still available for the R90s and later bikes, and that it would all fit on my bike, without modifications. Below are comparison pictures of the old and new parts, click to enlarge…

Up Next: Yank My Flywheel!


Das Bike Projekt: Inspecting the Clutch

Pulled the transmission to get at the clutch, found lots of gunk in the bellhousing, something is leaking, and once the clutch was apart we can see that, yes indeed, it has been “slipping a bit” kind of a BIG bit, actually. Click on photos below to enlarge!

Up Next: How to build a better clutch?


Das Bike Projekt: Inspecting the Final Drive.

Well the deeper we get, the more we learn, right? SO, In a nutshell we have fluid leaking from the driveshaft tube into the final frive, then out of the final drive into the brake drum and onto the brake shoes. So I will buy the tools to blow apart the drive and replace some seals. Also we have an alignment issue. Remember that the earlier /2 bikes, and the later /5 bikes have very different frames. The motor looks like a bolt in, but it isnt. one issue we have is that the driveshaft is too short, so you either have to insert a spacer, or use the shaft from a later bike. I remember asking which method he used. I think i remember him saying he replaced the shaft. He did not. The input drive gear is heavily worn JUST on the front 1/3rd of the gear. So thats 2 more expensive parts i need to order, the gear, and the spacer.

This slideshow requires JavaScript.




Anke-Eve does not have a leaky final drive!


Das Bike Projekt: Removing the Driveline.

Well time to reveal more mystery! The previous owner says the trans was “clunky” and the clutch was “starting to slip” I secured a cheap, low mileage 4 speed trans, so I will pull the existing one, and pull the clutch and flywheel while we have it apart…. also i will have to have a look at  and so on, the rear main seal, the rear drive seals….

This slideshow requires JavaScript.

Up Next https://kirkusblog.com/2011/02/19/das-bike-projekt-inspecting-the-final-drive/