K75S no drive?

[MikeP]

I'm sure it's been repainted-not a bad job and some while ago I would guess-panniers are also in yellow. Its not my favorite colour-attracts kamikazee insects and incontinent birds! What colours did they come in and where can i get matching paint for those colours?

Don't know anything about these bikes so any info/help greatly appreciated.

John

The most common red for K75S models was Marrakech Red but they also did the S in Mystic Red and one other the name of which escapes me.

Is the paint code label still under the seat by any chance (they tend to be in the same place on all the bikes)?

Failing that, a BMW dealer will tell you the original colour from the VIN.

 

[Lord Snooty]

For colour codes look here http://www.bmbikes.co.uk/schemepages/schemek75s.htm

 

[The Grey One]

Thank you both for the info. The paint code is there but it has been painted over!

I rather like the blue but it looks like it would be wrong for this bike-is that the case?

The bike looks to have been well cared for mechanically. It has obviously new tyres (well new when the previous owner left home in Scotland!) A new radiator, and various other signs that it had been serviced before the trip. The frame has lots of surface rust and the paint on the engine, gearbox, and final drive has seen better days. Apart from the screen most of the panels are either OK or just in need of minor repairs. Except for the tank all will need repainting so it's not a major step to change the colour.

What do the team think?

John

 

[Lord Snooty]

John, these are great little bikes and seriously under rated as BMW tended to push the 1000cc 4cyl. The 3 cyl is much smoother - I have had mine for about 3 years now and I've put 45k miles on it and use it every day for instructing. I put a new clutch in at 90k and it has just had a new drive shaft at 104k. Get it revving at 5k or more and it comes on song. It will be well worth the effort in tidying it up and then enjoying riding it.

 

[Steptoe]

I want to get the shaft out but can't see how the r/h arm pivot comes out-on the left hand side there is a big nut and an Allen screw but on the right hand side there is a circular plate held in with three Allen screws. Where do i go from there-I don't want to damage anything so it would be nice to know how it comes apart rather than forcing something and making a mess of it. Any advice would be very welcome. If it turns out to be just the driveshaft I think I will be playing with the bike over the winter to get it back on the road next spring.

John

Only just seen this thread - You don't have to remove the swinging arm to remove the drive shaft.............

Very simple. Clamp the end of the drive shaft that's sticking out of the swinging arm with a vice grip. Hit vice grip backwards with a hammer.

 

[Steptoe]

I rather like the blue but it looks like it would be wrong for this bike-is that the case?

The blue was an official BMW K75S colour.

They also came in red (various shades), blue, Purple, brown (mikeP's old polished turd bike), silver, solid black and shwartz black.

 

[The Grey One]

Only just seen this thread - You don't have to remove the swinging arm to remove the drive shaft.............

Very simple. Clamp the end of the drive shaft that's sticking out of the swinging arm with a vice grip. Hit vice grip backwards with a hammer.

Thanks, I did know that but I wanted to dismantle a bit further to check the bike out before deciding what to do with it,

John

 

[The Grey One]

Question number 1

OK this is getting serious now, I started out thinking I would just check the splines on the gearbox then put the whole thing back together, give it a cosmetic once over and back on the road. I find I am enjoying working on the beast and although basic by modern standards it looks properly engineered. So a little bit more dismantaling is on the cards. Might as well check the clutch having got this far. It looks to me that if I support the bike under the sump I can take the gearbox off easily.

My question is am I right or are there any hidden pitfalls? At the moment I have no manual or other technical information to help. I do have 30 years of previous experience of working on Citroen cars. This includes vehicle restorations often involving a "last nut and bolt" strip down. I have a good tool kit but right now the GS is on the bike lift (gearbox out-waiting for anew clutch) so I am working on the floor which is not good for my old joints.

Thank you in advance for any tips, I learnt many years ago that people who have actual experience of these jobs often know better than those who wrote the manuals.

John

 

[Duc750]

In simple terms yeas although I've always found it more stable to sling it from the rafters on ratchet straps.

The thing to keep in mind is the clutch pushrod is very easy to bend so do what you can to extract that first (through the clutch release bearing) and you should be fine.

The easiest way to snag the box I find is to sit underneath the bike and wriggle the box back wards on your knees - its not that heavy and if you take the main stand off its pretty smooth and easy to handle.
Beware the torque settings on re assembly as they are a lot lower than you think.

BMW club have the workshop manuals if you're a member and I think they are on Motobrick.com too.

They are nicely engineered - to be honest I got ine as a stop gap before getting a GS (hence being a member here) and have never quite found a GS I want enough to get rid of the K

 

[The Grey One]

In simple terms yeas although I've always found it more stable to sling it from the rafters on ratchet straps.

The thing to keep in mind is the clutch pushrod is very easy to bend so do what you can to extract that first (through the clutch release bearing) and you should be fine.

The easiest way to snag the box I find is to sit underneath the bike and wriggle the box back wards on your knees - its not that heavy and if you take the main stand off its pretty smooth and easy to handle.
Beware the torque settings on re assembly as they are a lot lower than you think.

BMW club have the workshop manuals if you're a member and I think they are on Motobrick.com too.

They are nicely engineered - to be honest I got ine as a stop gap before getting a GS (hence being a member here) and have never quite found a GS I want enough to get rid of the K

Thanks No chance of hanging the bike off anything in my garage! I didn't know about Motobrick.com so thanks for that too. hopefully I can find a downloadable manual so I can print out what I need - always was a messy worker so books quickly become unreadable.

I keep taking more off the thing so this might end up as a full rebuild. I will try to post more pictures as I go along.

John

 

[MikeP]

I prefer to jack the bike under the engine just ahead of the bellhousing.

Remove the battery tray and undo the two allen screws that hold the starter in place (I find it easier to remove the starter and the alternator).

Undo the four bolts that holds the stands sub-frame to the underside of the gearbox. Both stands will come away with the springs and all together.

Undo the push-fit cable connector from the gear position switch indicator (up by the frame under the rear of the fuel tank).

Slacken the clutch-arm at the clutch push-rod and disconnect the clutch cable from the arm - withdraw the cable through the gearbox casing.

Support the gearbox and release the six allen screws that secure it to the bellhousing, then the upper gearbox to frame bolt followed by the two side frame to gearbox casing bolts (take note, the nearside one may have a shim packing between the down tube and the gearbox casing).

There are a couple of alignment dowels so it needs to come back before it will disengage from these.

Pull the gearbox out to the rear.

Piece of piss. Have a look through some of my K-Bike clean-up threads and you'll find photos.

 

[Duc750]

The "American" technique (I say that as I've never seen it advocated on a european forum) is to stick a saw horse under the rear fairing hoop.

There's nothing wrong with supporting it under the sump its just I've never found it very stable that way.
In fact I believe the BMW "special tool" does just that on the 1100 and olts on to the crash bar mounts

If I still had my old Draper transmission jack however that would have been perfect for the job

 

[MikeP]

Jacking beam underneath and one strap over the front of the bike works for me.

 

[The Grey One]

Thanks to Duc750 and motobrick I now have a manual. From MikeP a picture of how it should look. Thanks to both for the advice, it does look easy enough.

Apart from the clutch is there anything else I should check for?

I have removed the radiator, why does someone fit a new rad with the old rusty bolt, not even a sign of copper slip etc? I wanted to be able to clean up and re paint the black engine casings and as a hose looks to go through one side I thought I might as well take it all apart!

Thanks again for the help-I might need a little more before I'm finished.

John

 

[DrFarkoff]

Apart from the clutch is there anything else I should check for?

Clutch Pivot arm siezes Do NOT beat the pin thru because you'll break off the lug (s) back of the gearbox

Exhaust nuts studs if they come off replace them with the bmw brass nuts (you can cut them off with a chisel if the need arises unlike stainless ones

I am sure some more will appear for you as you progress

Good Luck

 

[MikeP]

Check the alternator drive. The rubbers often go brittle and collapse with age. This can then lead to the blades in the drive snapping.

Steptoe says that the 75 models are more prone to failure than the four cylinder models for some reason. Of the four I've hoiked out recently he's right (as usual); two K75s both with crumbling cush rubbers, one with blades broken, two K1s neither showed any real signs of wear.

I have another K75S in pieces at the moment, I've only just started on it but I expect the rubbers will need replacing.

 

[DrFarkoff]

add a 4th one here Mike K75RT 2 blades broken in the drive as well Strange that as they are supposed to be smoother running

Check the alternator drive. The rubbers often go brittle and collapse with age. This can then lead to the blades in the drive snapping.

Steptoe says that the 75 models are more prone to failure than the four cylinder models for some reason. Of the four I've hoiked out recently he's right (as usual); two K75s both with crumbling cush rubbers, one with blades broken, two K1s neither showed any real signs of wear.

I have another K75S in pieces at the moment, I've only just started on it but I expect the rubbers will need replacing.

 

[Duc750]

You can upgrade to a bigger alternator at the same time - the later K1100 alternator is the same as the oilheads. (with the K drive cup) and its also the same as a 1998 1l vw polo.

Its fully rebuildable and the reg rec and bearings are easier to get than the earlier one.

Clutch actuator arm is a good shout too but keep in mind the circlips that hold it are made of cheese and I doubt you'll get them on and off!
(that could just be my "sausage paws" though)

The biggest watch out though is the clutch pushrod - they are very easy to bend and obscenely expensive to buy for what they are ! DAMHIK

 

[The Grey One]

Please adopt smug mode!

You guys were right about the alternator drive rubbers, just starting to break up as you can see. Got the gearbox off with no problems, clutch is almost worn out. There is oil all around the bell housing, I guess it's the crank seal. I'll find out when I next get a chance to play-got some actual work to do now.

 

[seahorse]

You can upgrade to a bigger alternator at the same time - the later K1100 alternator is the same as the oilheads. (with the K drive cup) and its also the same as a 1998 1l vw polo.

Correct but be aware that the block connector is different.