Clutch Doesn't Want to Disengage When Hot

Yes, the clutch rod must have clearance. The riders handbook describes the clutch setup precisely.

Deets55 said:

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.

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kerosene is a good lapping agent. If you want to wear out your chain etc, then be my guest. I use the 20-50 oil I put in my engine, no probs. Clutch plate a re designed to work with oil.

Go back to basics. free up your clutch cable the do the adjustment at the clutch. I had a similar prob. I ended up removing the clutch assy. to find a P.O. had used a copper washer under the nut on the clutch assy. i.e. at the clutch end of the diagram above. This was a temporary cure because it happened again. This time I took the outer cover off my g/bow, removed the clutch throw out mechanism and found the nut on the main shaft had turned in to a bush. Metal filings everywhere.Ended up doing and rebuild with new bearings and selector fork [ fork had only 1 side of the yoke intact ]. I also proved you could rebuild on of these gearboxes without taking the thing out of the bike.
Loctite that bloody nut on the shaft as there is no locking device used.

texasSlick said:

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

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Yup, gear oil will cause a DRAGGING clutch on these. :shock:

rick in seattle said:

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.

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Media blasting clutch plates is a step in the wrong direction, friction wise, just for others who may think of trying it. :idea:

Slick,when I take the primary cover off I'll check the stack height and get back to you...Skip

Probably just taking the clutch apart and cleaning the all the plates in your favorite solvent will fix it. This used to be an every Spring event for me but I put in the dynodave seal and have not done it for a couple years now.

Also, check that the clutch actuating lever on the right side of the gearbox (where the clutch cable attaches) has not dropped down so it is off the cam.

kerinorton,

I didn't mean for Skip to drive the bike with the kerosene in the primary. I was just suggesting for him the wash out the chain case and plates with kerosene, then DRAIN and fill with oil of his choice. Then if the problem goes away or gets better he has identified the problem and continue with proper repairs. i.e. clean plates and adjust clutch properly.

Pete

I have had my Norton for 39 years and never had problems with gear box oil getting into the clutch, never over fill your gearbox and what I do is put grease on the clutch rod and no oil gets into it, fill up your gear box to what the manual tells you and you should have no problems with over fill.

I have filled my primary with early Ford transmistion oil and has worked the best sinse owning my Norton, better than eneything else that I have used and I am still using the same plates from new.

Ashley

I'm still on my original plates too at 14K miles. Stack height is within spec, but could be a tiny bit higher. I've tried extra plates but they are all too much. Clutch slips with any more height.

DynoDave's site is good, but I had to read it 10 or more times to figure it out. I've got his seal, but not sure it's necessary unless you're using syn oil in the trans.

Here is info on setting up clutch stack height.

http://www.oldbritts.com/ob_clutch_info.html

I think your first step is to empty the clutch basket, wash the plates in solvent, inspect the center for cratering (or notching). check the actuator mechanism in the gear box as someone suggested. You will need a tool to remove the diaphragm, or PM me and I will send you a sketch on the home made rig I used.

I do not have the link available, but someone sells thin shim plates.....example 20, 40, 60 thousandths, which can be used to get the stack height just right to obtain "break over" like a compound bow.

Gearbox oil can cause dragging, but I wrote I did not think it was the cause of your problem, as it GB oil contamination would be worse COLD than hot. Install Dyno Dave's seal....it is a good prevention and only $30. Dave's site AtlanticGreen has more info on clutch setup as well.

Keep us informed how it goes.

Slick

You can buy a plain barnett plate for about $20, I think that is about the thinnest one available. I tried one, but it made the pack too high and the clutch slipped with it. OB will send you a whole bunch for $100 or so and you can send back what you don't use for a refund. I tried it and it didn't work for me.

Dave my orginal clutch plates have over 140,000 mile on them now and the only thing I have replaced in that time was the pressure plate as it lost its power, and just recently I replaced the clutch centre as it was to notchy, so I have found out the bronze plates will last a long time and my Norton use to cop a hidding when I was young and silly, I still ride it hard but with a lot more care and as much maintenace when needed.

Ashley

ashman said:

and my Norton use to cop a hidding when I was young and silly, I still ride it hard but with a lot more care and as much maintenace when needed.

Ashley

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'Cop a hidding' is not in my American vernacular.

I'm really surprised how much the original parts hold up without abuse. My fiber plates have the postage stamp fibers on them and like I say the stack height is good.

I don't ride mine hard any more, I feel too fragile and have a fractured but repaired neck. I even worry about going up on ladders. But I don't mind riding around the back roads at 50 mph or so. It's always good to feel that 2nd gear. 1st gear always gives me a start especially when going down the gravel road on a 20 degree hill from the house.

Dave
69S

DogT said:

I'm really surprised how much the original parts hold up without abuse. My fiber plates have the postage stamp fibers on them and like I say the stack height is good.

Dave
69S

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Not a hyjack but this brings up a thought, my new Barnett plates have the postage stamp fibers also, different from my last set of Barnetts. They work just as well but offer a bit of a squeal from a stand still.

Deets55 said:

kerinorton,

I didn't mean for Skip to drive the bike with the kerosene in the primary. I was just suggesting for him the wash out the chain case and plates with kerosene, then DRAIN and fill with oil of his choice. Then if the problem goes away or gets better he has identified the problem and continue with proper repairs. i.e. clean plates and adjust clutch properly.

Pete

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thank goodness for that. easy to misread with this dyslexic brain of mine.

I generally use petrol to wash my clutch parts then finish off with brake clean. both evaporate away quickly. kero doesn't. Because I have 2 bikes, most I ride one, the other ends up with a rusting clutch so I use both more often now. A mate with a triumph once suggested I pull in the clutch then kick it free, before starting.. That certainly helps with the initial drags that sometimes happens. { like to hear the silence when I engage 1st gear, unlike other bikes [Tractors oops Harleys ] that crunch when doing same } [ have to admit Harleys have good g/boxes. they change nicely when you put your foot on the l/h foot peg HA HA ]
I havnt had the problems experienced above after I have worked on either of my bikes. The 750 still runs the original clutch [ which did start slipping many years ago before the major rebuild ] My 750 sat round unused for about 15 years while my kids were growing up, so rusty chrome resulted all over. The major rebuild happened after the original ball timing side main brg shat itself one day about 6 years ago. When I first got the 750 [ and before my brain became educated] the clutch was really heavy and I wore out a pair of gloves on it. After brain became more user friendly, I fixed the problem by carrying out the std adjustments. really simple.

I have the "clutch" tool for taking the clutch basket apart. I thoroughly cleaned the plates and checked for flatness .Everything was fine.The clutch center hub looked brand new with no notching. I'll play around with the stack height.

As a side no,te some of you know that I rebuilt my bike from a derelict bike that had been sitting in a junk yard for maybe 25 years. It was a mess,but.....the primary contents all looked brand new as though the previous owner had just replaced the stuff before blowing up the gearbox,which I feel was the cause for it sitting in the yard all of those years....who knows??

Anyway the bike is running great inspite of the clutch not being 100%.I'll get it right!

Theres a ancient post here about the little hoodady the cable fits to . Apparently its all in the action there as to it being light and easy .

fully in , assume its ' Over Center ' , so you can hold it in at the Traffic Lights . :shock: :lol:

maybe a afficianado of this adjustment would speak up .

Skip:

Glad to hear there is no notching on the clutch center.

Clear one thing up for me....when you write "clutch does not disengage".... do you mean "clutch drags when fully pulled in"?

It is not just semantics....conjures up two different things in my mind, and perhaps others.

one other thing to check: the circlip on the main shaft. Too much torque on the main nut can dislodge or deform it, and may contribute to erratic clutch release.

I think Matt's "hoodady" is the cam plate in the gearbox. Dyno Daves Atlantic Green site has more info on that. The Atlas cam has more mechanical advantage, thus gives easier pull, but less linear travel. Less travel could result in clutch drag.

I converted my Atlas to a Cdo clutch, and had quite a time getting the stack height just right to balance the three factors of 1) easy pull in, 2) no slip under WOT, and 3) no drag.

Keep us informed.

Slick