Clutch Doesn't Want to Disengage When Hot

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phillyskip

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I have about 400 miles on my recently finished 72 Commando and things are going well,but do have one problem. When coming to a stop my clutch plates don't want to disengage. If the clutch lever is pulled in and I blip the throttle I can get them to break free. I have a stock clutch with the plates that have the concentric grooves in them. The clutch pull is light,I'm using the Venhill cable. I have tried using 5 to 7 ounces of ATF,Synthetic ATF,and 20/50 wt oil. I have found no difference using different oils. I've asked a few Norton buddies their opinion on this problem and get very different opinions. So tell me, what do I need to do to get my clutch to operate properly? Thanks, PhillySkip
 
phillyskip said:
I have about 400 miles on my recently finished 72 Commando and things are going well,but do have one problem. When coming to a stop my clutch plates don't want to disengage. If the clutch lever is pulled in and I blip the throttle I can get them to break free. I have a stock clutch with the plates that have the concentric grooves in them. The clutch pull is light,I'm using the Venhill cable. I have tried using 5 to 7 ounces of ATF,Synthetic ATF,and 20/50 wt oil. I have found no difference using different oils. I've asked a few Norton buddies their opinion on this problem and get very different opinions. So tell me, what do I need to do to get my clutch to operate properly? Thanks, PhillySkip
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Are you running a belt of chain primary?
 
Take the inspection knob off the primary case (clutch) .. unlock the locknut and screw in the centre bolt 2 full turns IN, if that dont work good enough do another 2 full turns in.. You will certainly feel changes i believe, and it will also adjust your "take up" position on clutch lever...... If that dont work then i think its probably the clutch centre hub may have some excess wear...

what is the history of the clutch ????????? any recent upgrade or mods in this area ????
 
Any cratering on the center body of the clutch? Cratering are dents or gouges in the splines that cause the plates to hang up, rather than shift freely when the clamp pressure is removed.

Slick
 
Notched center most likely culprit. Expen$ive. Contaminated plates from drifting gearbox oil. Buy mainshaft pushrod seal kit. Not so expen$ive. :|
 
Torontonian said:
Notched center most likely culprit. Expen$ive. Contaminated plates from drifting gearbox oil. Buy mainshaft pushrod seal kit. Not so expen$ive. :|
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In the event PhillySkip is not familiar with the jargon, cratering and notching are the same thing.

I do not see how gearbox oil contamination, will cause his problem....might cause slipping clutch however.

Slick
 
Clutch Doesn't Want to Disengage When Hot


just n case . these olde engish machines ARE NOT supposed to sit at TRAFFIC LIGHTS in gear . Clutch in .
The wee pushrod end gets all hot & bothered , detempers , and goes walkabout .

Bit like sitting at the lights in your car with it in gear or drive , excess wear . thrust bearing goes awol .

or driveing useing you clutch as a footrest . metal dfective with white gumboots in Triumph 2000 ( car )
disagreed that was why the clutch was slipping . " can you tell me why my clutch is slipping "
YES
" but I like my gumboots "
p.s. he was from coromandel .

SLIP IT IN NEUTRAL as you COME to the lights . a ounce of prevention beats a pound of cure , particularly todays pound .
 
Steel Plate CLUTCHES had HARDENED CENTERS / ( Hubs ) .
fitting em to early suckers can get the result pictured .
Unless you fit the hardened hub.
If you ride it .

as above.

Clutch Doesn't Want to Disengage When Hot


anyone seen something like this for them ??

Clutch Doesn't Want to Disengage When Hot
 
Good pic of cratering, Matt!

Shifting to neutral when standing at lights is good advice with MC or manual transmission auto.

Cratering is mainly caused by wheelies, power shifts, and such, although "soft" metallurgy may be a factor.

Slick
 
Might be oil on clutch plates causing them to drag. Try draining primary oil and pour diesel or kerosene in primary ( no t gasoline). Start the bike and let it idle. While idling pull and release clutch lever to clean off plates. Do this for a couple of minutes. Then drain while still warm. While bike is draining adjust clutch according to manual. Fill with 5 oz of oil (I use straight 50 in summer). Then take it for a ride. If that helps you know you are looking in the right directions. I use about a pint or so of kerosene. Look into Dyno Dave's clutch shaft seal. It help with mine.
 
Might try loosening the triplex chain a bit and see if that helps.
 
DogT said:
Might try loosening the triplex chain a bit and see if that helps.
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I agree. Although 3/8 is suggested, that is as tight as you would ever want it to be IMHO. I might think that a notched center would effect function Hot OR Cold.
 
Skip,

I had a similar problem which ended up the clutch hub bearing was seizing up. I had my primary chain too tight.

Make sure your chain is not tight and pull your plates and give the clutch hub a spin.
 
Further whineing , but . . . If you make a habit of slideing it , traffic - lane splitting or a steep drive etc , they gook up & bind and slip a bit .
Rather than BITE and Free .

So the ideas to let it IN on a light throttle , and disengage fully at the min non snatch speed , then let in again . NOT trundle along letting it slide .

the gook ( worn friction material ) forms a gunkey paste on the clutch plates . This makes the action soft and indeciseive , or slow .

letting them slide full whellie can roast and buckle them , though a quick blip or two might clear the gunge .
 
My 69 750 dragged like a bitch, plates contaminated with gearbox oil coming up the pushrod tunnel. Fitted dyno Dave's pushrod seal and I have a no drag clutch!
 
Thanks to everyone for their tips. I adjusted the clutch center nut for more pre load and she's working much better now. The next thing I'll do is check my primary chain although I don't think it's overly tight. Just want all to know that I appreciate your help.....Skip
 
I'd rather have a loose primary chain than a tight one. Shifts better, and the bushings in the GB last longer, plus you can really screw up your mainshaft with too tight a chain. It's my understanding they tighten up with heat too.

The setting on the clutch rod adjustment on my bike is very critical to correct clutch operation. If it's adjusted right the clutch lever should feel like a compound bow breaking over when the lever gets near the grip. That's the clutch diaphragm breaking slightly over center. And it should be easy to hold there, not a chore. There's no way I can play with full turns on the adjuster, it's 1/8 turns for me that makes all the difference. YMMV.
 
Skip,

If you search the board archives, you'll find that the majority of the sticking clutch problems were solved as Torontonian described. When I rebuilt my Mk3 nearly 4 years ago, I used the existing plates, as they looked great. I could not clear the clutch (in neutral, pull in the clutch and kick through-should be no resistance), and no amount of plate cleaning/media blasting could prevent the sticking; the fiber plates were simply too contaminated. New plates and a Dave Comeau seal solved the problem and spared me the expense of a new clutch center piece.
 
phillyskip said:
Thanks to everyone for their tips. I adjusted the clutch center nut for more pre load and she's working much better now. The next thing I'll do is check my primary chain although I don't think it's overly tight. Just want all to know that I appreciate your help.....Skip
Click to expand...

If you do not have some free play in the clutch lever, you have adjusted the clutch center nut too much! If too much, you will be riding the release mechanism. This is not the way to achieve DogT's recommended break over...that must be done by adjusting the stack height with shims, if necessary.

Slick
 
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