Clutch adjustment

[Duane Ausherman]

I posted this on the engine case cleaning thread, but have now moved it here.

I can't believe this thread. There is a huge misunderstanding of the clutch as related to shifting.

In a perfect world the clutch arm would be at 90 degrees to the clutch rod. Is it important? No, as the most variation that one can get is very little. At worst case one might end up with a 1% energy trying to shove sideways. Forget about it.

By varying the ratio between the adjustment at the top end and at the bottem end will change the angle of the clutch arm. All could be correct, but give a different measurement of this 203 mm thing.

When the hand clutch lever is out, you must have a bit of free play. The clutch does heat up during operation and will change the amount of free play. As it heats up, the free play decreases. Too little free play and you will risk excessive wear on the pushrod end and the hole it sits in. This would be the same as riding around with the hand clutch lever partially pulled in. That would cause heat and wear. As free play decreases, the clutch if even more disengaged when the hand clutch lever is pulled in fully. This would tend to make it shift even better.

Take a look at the easy clutch modifications. In those types of mods, a 2:1 advantage is used to decrease the pull resistance. The "cost" is that the total travel is now 1/2 of before. When properly ajusted, they work just fine. If our clutch can work with 1/2 of the standard travel, just how hard can it be to get the stock setup adjustment in the ball park?

OK, does this make any sense, or should I go take my meds? Again!

All that is important is that the clutch release fully when the hand clutch lever is fully pulled in. Variations in clutch cable stretch, aftermarket cables, friction plate wear, pushrod wear, wear in the Diaphram hole, wear at the adjustment bolt, wear in the pivot arm shaft, wear on the inside of the clutch arm etc. The list goes on and on.

We humans tend to obsess over trivia and often fail to get to the heart of the matter. Rather than actually "learn" we prefer to follow hard and fast rules. In this case, rules that don't really work. All rules have exceptions, so learn the rule and then learn the exceptions too.

[the quinner]

All that is important is that the clutch release fully when the hand clutch lever is fully pulled in. Variations in clutch cable stretch, aftermarket cables, friction plate wear, pushrod wear, wear in the Diaphram hole, wear at the adjustment bolt, wear in the pivot arm shaft, wear on the inside of the clutch arm etc. The list goes on and on.

This over simplifies the issue...

I OFTEN get bikes in my shop that have the clutch arm resting against the rear/lower cross-member of the frame. On those bikes, pulling the lever in DOES fully disengage the clutch...however, releasing the lever does not fully engage the clutch...allowing slippage, glazing and leading to premature failure. The positioning of the rear clutch arm does matter.

[Major Softie]

OK, does this make any sense, or should I go take my meds? Again!

We humans tend to obsess over trivia and often fail to get to the heart of the matter. Rather than actually "learn" we prefer to follow hard and fast rules. In this case, rules that don't really work. All rules have exceptions, so learn the rule and then learn the exceptions too.

There is one rule that has no exception: no matter if you're making sense or not, you should always go take your meds.

[Jeff in W.C.]

We humans tend to obsess over trivia and often fail to get to the heart of the matter. Rather than actually "learn" we prefer to follow hard and fast rules. In this case, rules that don't really work. All rules have exceptions, so learn the rule and then learn the exceptions too.

I believe we humans try more often to curse symptoms than causes. But, I like yours as well.

[Deleted User 62]

We humans tend to obsess over trivia and often fail to get to the heart of the matter. Rather than actually "learn" we prefer to follow hard and fast rules. In this case, rules that don't really work. All rules have exceptions, so learn the rule and then learn the exceptions too.

I believe we humans try more often to curse symptoms than causes. But, I like yours as well.

I guess we will have to rewrite history: "Damn the symptoms, full speed ahead!"

[dougie]

I believe we humans try more often to curse symptoms than causes. But, I like yours as well.

Is that 'curse' or 'cure' ?
Or both ?

[chasbmw]

As I understand it, back in the day BMWs clutch adjustment advice was to try and get the adjustment arm at the gearbox arm at 90 degrees, then make sure there was enough free pay at the handlebar end. ( I don't have my old/6 handbook to hand)

But nowadays the advice is to use the 203mm measurement on both the light and the heavy flywheel bikes. This puts the clutch arm in the best position to operate the clutch pushrod, however much play is in the various components making up the clutch operating system. You then use the bolt on the clutch arm to create enough free play at the handlebar. it may sound anal and impossibly precise , but in my experience it works to create a much cleaner gear change. Being a pragmatic person if the rule works I use it.

[Jeff in W.C.]

I believe we humans try more often to curse symptoms than causes. But, I like yours as well.

Is that 'curse' or 'cure' ?
Or both ?

Yes!


A little typo can go a long way a times

[Duane Ausherman]

All that is important is that the clutch release fully when the hand clutch lever is fully pulled in. Variations in clutch cable stretch, aftermarket cables, friction plate wear, pushrod wear, wear in the Diaphram hole, wear at the adjustment bolt, wear in the pivot arm shaft, wear on the inside of the clutch arm etc. The list goes on and on.

This over simplifies the issue...

I OFTEN get bikes in my shop that have the clutch arm resting against the rear/lower cross-member of the frame. On those bikes, pulling the lever in DOES fully disengage the clutch...however, releasing the lever does not fully engage the clutch...allowing slippage, glazing and leading to premature failure. The positioning of the rear clutch arm does matter.

Thanks for pointing out that a misadjustment can cause the clutch to release fully, but not engage fully.

[Kurt in S.A.]

But nowadays the advice is to use the 203mm measurement on both the light and the heavy flywheel bikes.

IIRC, the distance is 201mm. But what's a couple of mm between friends?

Kurt in S.A.