I need help putting my bike back together!

[MC Dig]

Hi,

I have a 1987 k75s with 44k miles  that I just bought this fall.  It was becoming difficult to shift and I started getting some false neutrals and transmission clunks after my first 600 miles.  So, after lots of research I figured I should lubricate the clutch spline and also the final drive.  So, I got the clutch spline lubed and the transmission back on and torqued.  My problem is that there is a tube about 18 inches long that I found laying by my bike and I am wondering where it goes.  Also there is a tube that is coming out of the transmission with a 90 degree fitting on the end and I am not sure where that is supposed to fit.  The last issue I have is that when I moved the clutch arm down, about a tablespoons worth of what looked like hydraulic fluid dripped out of the boot.  Is there some kind of lubricant I should be pumping back in there, or can I just slap it all back together? 

If anyone can help out with any of these, it would be greatly appreciated.  I also made a series of videos documenting the job so I will post those on you tube when I am done for other people's benefit. 

[Rick G]

The long tube is most likely the drain tube from the fuel overflow. There are 2 drain/breather tubes comming out of the fuel tank at the underside right rear, these drain into a small catch container which in turn drains through that tube to the right rear footpeg area.
The end of the second tube should have a filter sort of thing and does not go anywhere in particular but should be fastened well above the level of the gearbox end. It may be a positive ventilation device which probably fit into the airbox above the throttle bodies.
The fluid that came out is quite normal to be there and is oil from the gearbox. Make sure the rubber boot is in good condition as it is very difficult to replace it when it's all back together.
Don't put the clutch pushrod back in till the gearbox is bolted to the engine as it is very easy to bend it.

[frankenduck]

The tube with the right angle thing on the end is a battery drain hose.

[MC Dig]

How will I know if I bent the clutch rod? I put it all back together at the same time; and it did not go easy.

[MC Dig]

Also where can I buy a clutch rod for cheap in Los Angeles?

[frankenduck]

What makes you think the clutch rod is bent?

[MC Dig]

I'm just paranoid now because I put everything back together at the same time, and it was a pain getting it all back together.
 So if it could be bent so easily it may have happened.  I guess I can pull the rod out without pulling the transmission back off and check. 

[Rick G]

[/quote]

No, you need to pull the transmission.  Here's why:

(4V K bikes don't have that.)

The pushrod is pretty stout.  I think it would be hard to bend it.
[/quote]

I wish that someone had told my K100 that about 5 years ago. Both my 2Vs come out the back K100 08/90 & K75 09/90.
I didn't know there was any other type of pushrod.

[frankenduck]

I wish that someone had told my K100 that about 5 years ago. Both my 2Vs come out the back K100 08/90 & K75 09/90.
I didn't know there was any other type of pushrod.

Really?  That's odd. I've taken a lot of 2Vs apart and all of the pushrods looked like that.

[Rick G]

My R80RT was like that, it could not come out the back and the first time I took the gearbox off the K100 I slipped a bit and bent the shaft.
I found then I could take them out the back and have always done it that way. The only spare I have is the same and came from a 1986 RT that I parted out. It is a bit different in that the end that goes into the center of the clutch spring comes out of the rod but that may be due to wear because part of the bearing carrier is stuck to the other end. These are strange creatures.
I came across a K75s about a year ago that had fork innards like a K11 and presumed they were all like that and said so then was informed that none came like that. :dunno

[MC Dig]

Interesting,
Thanks for all the information. 
Put it all back together tomorrow and hopefully everything will be good.

So just to be clear about the stuff coming out Of the clutch arm boot, if that is gear oil from the transmission does that mean there is a seal I need to replace?  Should I put some gear oil back in there before reassemby?

[Inge K.]

On the different K100`s which I have removed the gearbox it`s been possible to withdraw the pushrod out from the rear end.

According to the Haynes manual the pushrod with a flange at the front end is fitted on the K75`s only (and a different clutch), but never done any work on K75`s since it`s rather seldom bike here around among the old two valves.

But on the other hand, in the genuine BMW manual only the pushrod with a flange is covered both in drawings and text.   :hmm:

Inge K.

[frankenduck]

Hmmmm... I must have K75 on the brain.  In looking at the parts catalog it seems as though it's based on the number of cylinders, not valves, as all of the K75s have the same pushrod and all of the four cylinder bikes (2V & 4V) use another one.  So it looks like you can pull it from the back on 2V K100s. :embarass:

[Inge K.]

So just to be clear about the stuff coming out Of the clutch arm boot, if that is gear oil from the transmission does that mean there is a seal I need to replace?  Should I put some gear oil back in there before reassemby?

Quite normal that it is gear oil on the inside of the boot, as behind the pushrod piston it`s open area in to the gearbox.
It`s an seal in there, but it is to prevent the gear oil to reach the clutch via the pushrod.

But it could be a good idea to check your oil level after reassembly, if you did loose some oil during the work.
It don`t hurt to do it anyway, should be checked every now and then.

Inge K.