500 clutch adjustment

[Murf]

Hi
A friend of mine has a 1975 UK model 500/4 it’s a nice bike and runs well, the only problem is the clutch, he has not had the bike that long and we have not checked out the clutch in any way yet, I thought I would check out how to adjust it correctly before we delve any further.
The symptoms are:- it does not free off well and makes selecting neutral difficult to impossible. However the clutch also does not start to bite up until the leaver  is almost fully out.  The bike runs well and does not seem to have any clutch slip.
Any suggestions welcome,  he is not opposed to stripping it and using new plates or parts if that is what is needed.
Thanks

[Bryanj]

Probably doesnt need plates but i am guessing a new cable routed correctly plus remove sprocket cover(needs to come off to fit cable anyway) then strip out the clutch actuating screw and housing, it is not unknown for the housing to be cracked causing a binding problem.
You may find the clutch pushrod in two pieces, it is supposed tp be one piece, also the ball bearing in the actuator can easily get lost.

Parts book is in Ash's dropbox and actuator parts are available if not cheap.
Adjustment is in the manual also in Ash's dropbox

[deltarider]

To arrive at the optimal adjustment of the CB500 clutch is not easy. The Owner's Manual does not help*. What does help is to have a look at what goes on inside the left crankcase cover and... some understanding of basic physics. The problem lies in adjusting the lever's position relative to the cable. The cable must pull the lever at a tangent to the lever; this is the position in which the force applied will have its optimal effect resulting in less force needed at the handle.
When you remove the cover, you can observe how the cable operates the rotation of the lever. When the lever is:
a) too far towards its return spring or...
b) ... too far in the opposite direction, the cable will pull crookedly and the force is not transmitted properly, making it all feel stiff at the handle.
The adjustment must begin by positioning the lever approximately halfway so that you will have the cable pull perpendicular to the lever right when the clutch engages.
To do this, first fully loosen the large screw in the cover for clearance. The handle will then operate the lever without pushing the push rod.
Now you need to arrive at an adjustment with the cable pulling perpendicular to the lever, by adjusting the tension adjustment screw just above the cover. Not easy because you can't see the lever... so you need reference points, disassemble the cover maybe several times and take reference points.
Once this is done, adjust the free play by tightening the large screw in the cover to bring the snail into contact with the push rod, leaving a little play ofcourse.
If you would do the opposite: loosen the cable tension with the screw above the cover and/or the one at the handle, and then adjust the free play with the large screw, and then tighten the cable tension, the lever will be in a downward position toward the return spring; the cable will pull crooked, and the clutch will feel stiff. So important is to realise that you can have an adjustment "in contact with the rod" with the lever in various positions! But... you want the optimal position, the sweet spot so to say.
Of course, before all this, you need a cable in good condition, a rod that isn't broken in two, and a ball bearing...
The CB550's clutch is much, much easier to adjust, as you can actually see what you're doing.
* The procedure Honda recommends in the Owner's Manual and in the Shop Manual, may, may help on installing a new genuine 22870-323-621 cable though, but... I'm not even sure on this.

[Murf]

Thanks to both of you for such great info.
 I had a feeling the 500 clutch adjustment was not simple so that’s why we didn’t mess with it.  We will check out the components as suggested and if all ok have a go at adjusting it.
Thanks for such a comprehensive description of the adjustment process, where else would I have been able to get that 😄.  It might be a couple of weeks until we get to work on it but will let you know how we go on.

[Bryanj]

Not sure about Deltas instructions as i always found you needed as much movement on the arm as possible

[deltarider]

Not sure about Deltas instructions as i always found you needed as much movement on the arm as possible

A shorter way to arrive at a proper adjustment, might be possible by just trial and error.
BTW, Honda was not consistent in depicting the position of the locknut where the cable enters the cover. I have seen pics where it sat near the adjusting hexagon, other pics showed it down near the cover and even a pic where it was halfway, letting us wonder: where is it supposed to be?

[Bryanj]

I found that the best way was to turn the big alloy bit with a flat bar till no free play then move it to give a small amount of play, then take up most of cable play at sprocket cover but not all to leave easy adjustment at the bars

NOTE:-

There is a bulletin inAsh's dropbox where the modified later alloy screw part has a "notch" at one end of the slot which must be in a certain range

[deltarider]

I found that the best way was to turn the big alloy bit with a flat bar till no free play then move it to give a small amount of play, then take up most of cable play at sprocket cover but not all to leave easy adjustment at the bars
[...]

That's the procedure in the Owner's Manual and the Shop Manual. I have the feeling this procedure presumes a brand new clutch cable. I applied this working order last year having a clutch cable which has done over 60.000km. So I had zeroed the cable so to speak as if it was a new one and I ended up with a very stiff clutch, I can tell you. Now my cable, although it still slides as new, has stretched ofcourse. So I studied what actually goes on and I have managed to have a much lighter operation now by first compensating the cable for its wear by its hexagon adjuster and then position the big screw.
As mentioned before Honda was not consistent in depicting the position of the locknut where the cable enters the cover. I have seen pics where it sat near the adjusting hexagon, other pics showed it down near the cover and even a pic where it was halfway. Where would you suggest to have it?

[deltarider]

[...]
As mentioned before Honda was not consistent in depicting the position of the locknut where the cable enters the cover. I have seen pics where it sat near the adjusting hexagon, other pics showed it down near the cover and even a pic where it was halfway. Where would you suggest to have it?

It seems nobody has the answer.

[florence]

As a regular 500 rider, I have always found, like Bryan, that the best way is to take up all the slack against the pushrod with the slotted screw and then back off about 1/8th-1/4 turn, then deal with the cable slack via the cable adjuster.  Seems to work fine every time for me.

[deltarider]

As a regular 500 rider, I have always found, like Bryan, that the best way is to take up all the slack against the pushrod with the slotted screw and then back off about 1/8th-1/4 turn, then deal with the cable slack via the cable adjuster.  Seems to work fine every time for me.

Yes, seems about right, but it's definitely more than backing off just the 3mm Honda suggests. Where do you position the locknut, the one where the cable enters the cover?

[florence]

I don't have a standard cable so my answer might not apply to all but I tend to have the cable slackened off completely at the cable adjuster before I adjust the sprocket cover screw adjuster.  My aim is to take up slack between the clutch actuator and the pushrod first.  I imagine that due to it's spring action, the mechanism is at it's lowest point when adjustment takes place.  Then I deal with the cable slack separately.

[Murf]

Thanks everyone, we will try the slacking the cable fully off method first and see how that goes. If no better will have a look at the clutch as suggested by Bryanj. So starting easy and working up to the harder bits😁

It sounds like a black art just like the Brit bikes of the 60s.
I always imagined there was one old guy at the factory that could adjust clutches correctly and used to do all the bikes before they left the factory.  Being a crafty old guy he would never tell anyone his secrets of how he did it and therefore he could never be sacked.  Consequently the bosses just made up some method to put in the owners manual😂.

[deltarider]

Basically you want the lever to be in a position where it provides the longest arm the moment the pushrod contacts the ballbearing and ideally the cable then travels in the straightest way.
Oh... and after the adjustment that locknut should be turned down. I find it telling that nobody came with an answer. It tells me that maybe, maybe most of us have a problem analysing how it all works. I've owned my bike since 1980 and never studied where that nut should be after the adjustment. On the other hand... I never had a situation where the cable wandered away from where I had it set.

[florence]

I see what you are saying.  I thought it was a given that the locknut is run down at the end, that is what it is for.