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Al Eckstadt
Al Eckstadt
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I have a good friend who as amassed quite a few motorcycles over the years. He has mobility problems now and needs help with his "kids". I'm more than happy to help. I also get to ride stuff. I've put at least six hundred miles on his '48 Vincent Rapide, but that's another story. He keeps his bikes in a storage shed with a concrete floor and it gets pretty dank in there. At present he has three Triumphs with stuck clutches. In neutral, is is impossible to free them up. In fact, you can hold in the lever and start two of them. I'm suspecting that it has something to do with the steel plate rusting, but until I pull off a primary cover and examine one I don't know. I had ridden one of the bikes, a beautiful 1970 Bonneville that is very original. The clutch was fine, but after sitting for two or three months it is welded solid!


Of course it vibrates…what of it? If vibration is so bad then explain how the adult toy industry has done so well.

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1971 Bultaco Alpina 250
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What year are the bikes? If they are pre 1970 you can fill the primary will solvent and kick for a while. They will free up. Bikes made after that share primary and engine oil so this is not a good idea. Barring that, the routine way to fix that is to ride the bike and the clutch will eventually free up. This can be dangerous, so be careful.
There used to be an accessory gadget that would lock the clutch lever to the handlebar. End of clutch sticking...Haven't' seen one in years. Used on the brake side, it becomes a parking brake.
Cheers,
Bill


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This seeems to be more of a North American problem than anywhere else in the world.I did have one that stuck like that after about 3 years unused.

Tie the clutch lever back to the handlebar.If you can't free it up after a week,or if you're just impatient,leave it tied up and go for a ride.

You'll need to push the bike to about 5 mph when you engage 1st gear.It might free up after about 30 feet,or it could take a mile.You can change up and down gears without releasing the clutch,if your careful.Just throttle on and throttle off until it frees up.

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Sometimes when the kicker won't free a stuck clutch, try putting it in top gear, pull the clutch lever, and bump the bike forward and back. Safer than trying to ride it.


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It's perfectly safe to ride without disengaging the clutch.Half of my gearchanges are clutchless.

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Taking off from a standing start isn't a gearchange,although I've done that clutchless on Triumphs.A little wheel-spin never hurt anyone,but I will take my weight of the seat to show some mercy.

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Interesting. One bike is a 1970, the others are a '66 Thunderbird and a '67 Bonneville. What would be a good solvent? Kerosene? I'll be over to the shed today. I can bring some big zip ties and use those to hold the clutch levers in on each bike.


Of course it vibrates…what of it? If vibration is so bad then explain how the adult toy industry has done so well.

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1971 Bultaco Alpina 250
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...you have solutions as the other members say; but why do not open the primary?
Its so simple, then get off the discs, clean, put again the pressure plate and cover and just that. 30 minutes work.

--In my opinion having clutch is extremely important due is the only thing that can save (pull the lever) you if the motor stuck...in my experience, saved me 2 times; yes 2 times one conrod broke, even broke one of the crankcases and the bike slipped like 50 meters or so each time

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I use ordinary paint thinner, cheap at the hardware store. I think the preferred method is to dismantle the clutch.
But the real solution is the type of clutches you have in there. Keith Moore used to sell me a clutch pack the didn't stick, no matter what. My memory is a bit fuzzy, but I think he said that he bought them from Harris...
Bill


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Originally Posted by reverb
...you have solutions as the other members say; but why do not open the primary?
Its so simple, then get off the discs, clean, put again the pressure plate and cover and just that. 30 minutes work.
What are you hoping to achieve for that 30 minutes work,oil and gaskets?It will only happen again,just like it did the first time.
If you go for a ride you can fix it in maybe 10 seconds,and it's fixed just as well.Even if it took a few minutes of riding,it's still a lot easier.

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...as I mentioned, he s got other even simple solutions, but may be he do not want to take the bike for a ride in that condition, etc, so I stated that is not so difficult to open the primary and clean the discs...


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The plates that "never" stick are sold by Coventry Spares; any of their dealers can supply them. They are sold as Alton clutch plates, in a set. The part number is CS-3210.

In the meantime, the age-old secret for breaking them loose is to start the bike and run alongside 'till it's going fast enough to pull first gear, then jump on and ride it with the lever pulled in until it frees. This does require having a safe place to perform such antics.

Your friend should install a dehumidifier to protect these bike.

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I had this same problem with 2 Triumphs this year...the only real cure is to spend $50 and replace the fiber plates. I can't tell you why the plates go south but just accept the fact.

I kept forgetting to wire tie the clutch lever open.
The plates would begin to lock up within an hour after stopping the bike.

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Thanx guys, I found some releasable zip ties yesterday and put those on the clutch levers. The place where my friend stores his bikes has a nice little hill that I could use for the "unsticking ride" maneuver. I like the idea of the plates that don't stick and will investigate those and let him know what I learn.


Of course it vibrates…what of it? If vibration is so bad then explain how the adult toy industry has done so well.

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Your tie backs, in place for few days, will help.

I would warm the bikes up pretty fully and then pull the clutch lever in and give the bike a fairly lively series of handfuls. You might find you can then get into gear. Like a lot of stuff these clutches seem to like regular use.

If you take the plates out, a number of folk find boiling them in detergent helps. Ditto using ATF oil in the primary - provided the engine does not breathe into it, that is, ie the early bikes are fine.

It would be interesting to know how you get on. Running those machines for your mate sounds a good job to have :-)

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I need to post some pics of the gears I've pulled out of gear boxes with the teeth sheared off.

From people trying to free the clutch with the motor running. Riding the bike might free the clutch. Might not.

Take the cover off and clean the plates right then try not to let them sit so long.


Rich
"It's not always about going fast. Sometimes it's nice to slow down" (Wendy E.2016)

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Riding the bike always frees the clutch.With a little sense,there's no chance of breaking gear teeth.
I've got more chance of breaking gear teeth with a clutch that's already freed up.

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I've seen a mainshaft snap when someone didn't free the clutch. I then bought the bike off him for a song and bought a new shaft and fitted for 200 bucks.

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I suffered stuck plates when I built my bike and it sat for 3 months before being finally fired up.
Fix is to dismantle and clean it all up, get the oil/rust off the plates and coat them all with lithium grease then wipe it all off again so there is no trace left.
You will have the smoothest clutch ever after that and it won't stick again.
And for the curious, no it won't slip either.

davy

Last edited by Old Cafe Racer; 02/23/14 7:11 pm.
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Great responses guy. I try to be gentle on equipment and I'm not too inclined to attempt a de-sticking ride maneuver, particularly with someone else's bike. I'll check on them either today or tomorrow and see if the zip ties are helping. I run Belray Primary Oil in my own bikes. My clutch never sticks. Before a cold start I always hold the lever in while giving the starter a little shake with my hand and that is all that is required. If the zip tie approach doesn't get it, I'll likely open them up and see what's there.


Of course it vibrates…what of it? If vibration is so bad then explain how the adult toy industry has done so well.

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There's sticking where it takes a couple of kicks to free the plates, which has been considered normal, but then there is sticking where the only way to free the plates safely is to remove them and pry them apart. If you used the previous iteration of Barnett plates (a couple of years ago they changed the friction compound to one that is much less prone to sticking), and used them for racing you were always impressed at how much torque they could hold. The down side was, if you didn't either tie the clutch lever to the handle bar, or screw in the clutch rod adjuster, between races you were physically left with a clutch pack you had to remove and pry part. I hate the idea of using the clutch lever to hold the plates apart, as it puts undue stress on the cable fittings. You end up with a free clutch only to eventually have the cable fail in the race or down the road.

This is especially problematic if the clutch lever is set-up so the cable comes up taught before the lever hits the handlebar.

Probably the best all around clutch plate available, when one considers "value for money spent," is the Taiwan plate sold by Emgo, Wassell, or Harris. The narrow/modern facings of the 7 plate conversions work well with the 5 speed boxes with their "back cut" gears. The Alto plates have been sold under different brand names and are quite popular, but you should never use them with modern oils that have friction modifiers in their additive packages (use JASO MA2 rated oil only). And there is the old stand-by Surflex who still make a very useable plate (The 7 plate conversions use a plate made by Surflex).

If I was racing I would consider using a treated steel plate as they will seat the friction plate and allow the clutch to transfer more torque. For the street I would only use an ordinary untreated steel plate. There are a lot of people who have found considerable HP using the inexpensive Taiwan clutch plate.

Machinists are familiar with measuring tools called Jo Blocks. http://en.wikipedia.org/wiki/Gauge_block The effect that causes the blocks to stick together is not unlike what we experience with our clutches. The treated steel plate smoothes the friction material making it act like a Jo-Block. Great for some applications, but not for others. And any clutch discussion should include clutch springs as they are not made equally, and springs sold as "high performance" often are anything but.

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...so no Aluminum pressure plates?
What about the Aluminum pressure plates that have more "hold" area?

Also, no enhance to change them for a B Newby basket and plate? (letting the chain for the 650s)

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Quote
"hold" area?


What does that mean.

A clutch works around these basic points:
Coefficient of Friction (C.O.F.) of the clutch facing material. For a given material the C.O.F. will be higher when the material is used dry. Less when it is used wet with oil, and much less when used with oils containing friction modifiers!

Mean Effective Radius (M.E.R.) of the clutch facing material. Using a Triumph clutch plate for example, the narrow fiber facing of a 7 plate clutch plate has a greater M.E.R. than the stock plate. The higher M.E.R. factor will allow the narrower fiber plate to transmit more torque.

Clamping Force (C.F.) supplied by the clutch springs. This is strictly dependent on the combined pressure of the springs, not the width, or design, of the of the pressure plate. Total spring force of Triumph 3 spring vary from 90ish foot pounds (varies a bit with how they are adjusted) for the early unit springs (57-1560) to 150 foot pounds for the late T140 (57-4644). The highest spring rate available come from Precision Machine @ approx. 220 foot pounds (not recommend for anything but SERIOUS hp engines).

Total number of friction surfaces. The stock Triumph clutch has 11 friction surfaces. The 7 plate conversion ups the number to 13. The extra plate gives you about 10% increase in the torque the clutch can handle.

Did you ever wonder how a 200 h.p. Japanese street bike can use a clutch that is very similar in design and size to the Triumph 7 plate conversion? How do they do it with those skinny clutch facings, some of which are little more than 5/16" wide.

And an after thought: Remember those old cork clutch plates of days gone by? Well that cork had a pretty high coefficient of friction.

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I've said it a hundred times (well, maybe only 83) Cheap Emgo plates are excellent for general purpose use. Properly adjusting the 3 clutch springs to give just enough clamping force is best done before you re-install the primary cover. Take it out and test ride it to get the feel for where slippage occurs, then dial in just a tad more tension.

Problem only in the states? I hardly think so.

The Emgo plates in my race bike (near-stock '69 Bonny 650) have been in there since 2007, and have worked perfectly for over 30 races, a run down the Bonneville salt, 3 runs down the Texas Mile, and miscellaneous screwing around the neighborhood.

After about 4 or 5 races getting the hang of launching, I took the holeshot most of the time against better riders and faster bikes including Tridents, Honda fours, etc.

Just because they are inexpensive or are distributed by Emgo, DOES NOT make them inferior.

Last edited by GrandPaul; 02/24/14 2:38 pm.

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On a related note, overfilling the primary gets the plates oil-fouled quicker, then they stick together easier. The oil is for the CHAIN, NOT the clutch. Dirty oil sticks plates even faster, over-heated dirty oil faster still. The worse it gets, the worse it gets.


Last edited by GrandPaul; 02/24/14 2:41 pm.

GrandPaul (does not use emoticons)
Author of the book "Old Bikes"
Too many bikes to list, mostly Triumph & Norton, a BSA, & some Japanese
"The Iron in your blood should be Vintage"
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