Clutch Adjustment

[Mike V]

I have some questions regarding the clutch adjustment for the 650 even though it's working fine.

The book says the lever arm at the transmission should be at 4°. And, from the front of the throwout arm to the cable attachment at the case should be 201mm (+/-2mm) with the cable attached. I only have about 190mm with the cable attached.  Is there a static adjustment at the throwout arm without the cable attached?  And I believe the 201mm adjustment is to be done at the clutch lever (handlebar) adjuster, isn't that correct?

[Barry]

I believe the 201mm adjustment is to be done at the clutch lever (handlebar) adjuster, isn't that correct?  

Mike

Yes even though it sounds odd.

If  you are unsure if the clutch adjustment is correct the 78 – 80 riders handbook method gives an insight into what clutch adjustment is trying to achieve which is the throw out lever parallel at half travel. This is an exact quote :-

“The clutch is correctly adjusted when there is 2mm of play at the clutch throw out lever. In addition the clutch throw out lever must be positioned parallel to the gearbox housing cover while the clutch lever is half pulled. Deviations increase the force  necessary to operate it.”  

Note there is no mention of free play at the handlebar lever !!!  Presumably the correct free play is arrived at by following the above instructions precisely. As mine is an early model I’ve tried the clutch adjust this way and it is very difficult to do accurately.  I went to a lot of time and trouble to compare this with the later method  which as near as I can tell arrives at the same adjustment and is so much easier to do.

It’s no wonder then that the 81 – on instructions were changed to give the 2mm free play at the handlebar lever and the 201mm measurement of  exposed cable. They must have figured out that this would give a parallel arm at half travel.

[Bob_Roller]

I've always wondered what the big fuss over the clutch adjustment is .

The method I have used for 29 years, is get 3 mm free play at the clutch arm, to the clutch push rod, then adjust the knurled nut at the handle bar for 2-3 mm gap, and call it good .

I'm not quite convinced that it is critical to have the lever at a particular angle, I would think the condition and lubrication of the transmission splines clutch splines, properly lubricated cable and properly lubricated clutch push rod piston/bearing would be more of a factor on clutch lever forces .

Kind of the same adjustment technique I've used on all of the vehicles I have .

I replaced my clutch at about 80,000 miles, mostly urban riding, had about 5-10,000 miles left on it, but I had the transmission overhauled, didn't want to go back and do this in a couple of years .

[montmil]

I've always wondered what the big fuss over the clutch adjustment is.

It's almost as if an Italian technical writer wrote the section on BMW clutch cable adjustment.

[Mike V]

Barry, thanks.

At the risk of "fussying"...I have never had clutch problems either, and Bob as you mentioned; I've done the adjustment the same as you for many years.  But after a due-diligence check yesterday of all operating systems after over 1000 miles on the newly restored bike I wanted to see for myself about this measurement I've always heard about and never tried. It didn't measure as the book states which doesn't surprise me. I guess my main concern is while reassembling the clutch pack during the rebuild I had to back out the adjusting arm a few mm's to acquire freeplay at the throwout lever.  I never moved the locknut or adjusting screw on the throwout arm during the dissasembly which got me to wondering. As I stated the clutch (original) is working fine and smooth as glass with no slipping. I guess if it ain't broke - don't fix it.
But - to pass on some information; I'm finding lots of changes occurring to the carburetion and valve adjustment after the head and valve work and carb rebuild. I'll be performing my third head re-torque and valve adjustment this morning. Each time I've adjusted the valves they've closed up a hair and needed readjustment. And I won't get into the fuel issues I'm having although I'm finding that operation starting to settle in a bit.  I would imagine it's a direct relation to the valves. Originally the bike would barely run on the standard 145 main jets. I've done most of the break-in with 150 mains and went back to the 145's yesterday. Things are getting damn close to as perfect as i can expect. More miles = more better.  

[montmil]

...I'm finding lots of changes occurring to the carburetion and valve adjustment after the head and valve work and carb rebuild. I'll be performing my third head re-torque and valve adjustment this morning. Each time I've adjusted the valves they've closed up a hair and needed readjustment. And I won't get into the fuel issues I'm having although I'm finding that operation starting to settle in a bit... 

Valve lash has an effect on cam timing which has an effect on carburetion which has an effect on one's sanity.
Don't lose yours, Mike.  8-)