Wildguzzi.com
General Category => General Discussion => Topic started by: Rough Edge racing on February 28, 2018, 06:42:07 AM
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Clutch pull effort came up on Brit Bike ,a forum for vintage motorcycles,...Guys were going on and on but no one actually measured the clutch pull...So I did using this fish scale normally used to test steering stem preload, I don't fish :wink:
This is my Triumph race bike, about 18 pounds as measure 5-1/4 inches from the fulcrum....Most guys on the forum seem to have trouble pulling a lever with over about 12 pounds pull...I do not have a problem and find that is the clutch action is smooth and fluid like, the effort is less important..
More of interest here is the lever pull on my 96 Ducati 900 Monster with stock hydraulic clutch, about 16 pounds...81 Honda 750 with a new cable is about 15 pounds...
How about on you Guzzi?
(https://i.imgur.com/A6lh4AHl.jpg)
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I don't have a fish scale to measure, but, should get one.
I'm in the process reassembling my Eldo after a complete rebuild. With the old cable at least, the clutch pull effort is way more than any other bike that I've ever ridden. I'm going to get a Teflon lined clutch cable, hopefully, that'll make it better.
My little Ducati 250 single, with a new clutch cable, has a very heavy clutch pull. Also, my '73 R75/5 has a fairly heavy clutch pull. The vintage Hondas that I've had over the years, ranging from 175cc twins to a 1979 CB750 all had clutch pulls ranging from, subjectively, a little lighter than my 2014 V7 Special, to about the same.
My R1200RS has what feels like the lightest clutch pull of any of my bikes, followed by the Monster 796 (both hydraulic).
The lightest that I've felt recently was a 2017 Z900 that I demoed last year, which, despite being a cable was very light.
MG Cycle sells a hydraulic clutch slave cylinder that can be used to convert my Eldo to a hydraulic clutch, so, that may ultimately be the way I go.
I like a nice light clutch pull.
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I haven’t measured any of my bikes, but the ‘71 Triumph TR6R is the heaviest and the BMW R12RS is the lightest. The California Vintage is also fairly light. Clutches are like centerstands...some folks have more trouble with them than others.
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OK , I had to see. KLR 16+ Lbs
K75S 12.5Lbs
V11 Sport 15Lbs Hyd
SL70 9 Lbs
Paul B :boozing:
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I didn't like mine so I threw it away. Very liberating.
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a few of mine: V7sport, 24 Lbs
ducati 900ss ( bevel) 32 Lbs
enfield bullet 7Lbs ( and a slipping clutch)
with the ducati you learn to do clutchless gearchanges....
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I have a light clutch pull, Im using a ten spring with Barnett springs :evil:
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Interesting, now I need to get a fish scale!
I bet my 73' Laverda is the heaviest clutch I have ever come across.
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Interesting, now I need to get a fish scale!
I bet my 73' Laverda is the heaviest clutch I have ever come across.
laverda clutches are in a class of their own , a friend has a laverda 1200, he changes the clutch cable every 10.000 km because by then it is about to snap anyway....
the 1200 has basically the same clutch as the twins , but with stronger springs
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Interesting, now I need to get a fish scale!
I bet my 73' Laverda is the heaviest clutch I have ever come across.
My '73 Laverda brought tears to my eyes when caught in town traffic! It must have been in the 40 lb range. When new the factory fitted strong clutch springs to make up for the friction material of the time....so I was told by the guy who designed the engine. It was common to install a longer clutch lever in order to get more leverage but that also reduced the friction range.
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An alternative is the pulley device I saw on a Beamer recently, will take a picture next time.
It has a chain fixed to the chassis wrapped around a pulley on the clutch arm. The other end of cable is attached to the cable giving a 2:1 advantage.
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I wish I was up in Wisconsin with my fish scale. The Kid's 1100 spot has the heaviest clutch I've ever used. New (a little) thicker plates, new springs. You *don't* want to do stop and go traffic..
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It's too heavy on my 2009 Griso. Slow moving traffic is torturous.
Won't get to measure it before spring.
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If you could fix the problem for ~$150, would you?
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An alternative is the pulley device I saw on a Beamer recently, will take a picture next time.
It has a chain fixed to the chassis wrapped around a pulley on the clutch arm. The other end of cable is attached to the cable giving a 2:1 advantage.
http://www.benchmarkworks.com/articles/howto/clutch.html (http://www.benchmarkworks.com/articles/howto/clutch.html)
(http://www.benchmarkworks.com/articles/howto/clutch_files/clutch1.jpg)
I'm thinking about putting one of these on my R75/5. If I get one, I'll try it on the Eldorado first, and get a second one for the BMW if it fits the Eldo.
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If you could fix the problem for ~$150, would you?
I you're asking me? Yes, I think so.
Do you have a suggestion?
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That contraption above will reduce clutch lever effort and lessen clutch release travel at the same time? Harley used to have something called a Mousetrap in the 50's 60's ?
Wow, 25-40 pound clutch pull ? You got to measure them suckers..
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I you're asking me? Yes, I think so.
Do you have a suggestion?
Sorry if you read the previous version. It posted before I was done.
Yes, I do.
There are add-on hydraulic slave cylinders that will "pull" your clutch-side lever from the cable pull point. You'd need to come up with a mount, but some look to be as simple as a couple of U bolts around the frame rail. A radial clutch master cylinder (or flop your favorite Brembo radial pump) can be sized to fit. I'm currently using a flopped NISSIN pump from a Suzuki for my left hand pump on one bike, and a Brembo on the trike.
Here's a random example of the slave side. There are many size and mount variations. It's an average price.
https://www.ebay.com/itm/Wilwood-Style-Pull-Type-Clutch-Slave-Cylinder-260-1333/192419126888?hash=item2ccd12de68:g:92YAAOSw83taT~YS&vxp=mtr
I don't pay more than $75 for an 11/16 or 3/4 NISSIN radial pump. Usually the lever comes with. I pay more for a Brembo radial, but they have many more common sizes than NISSIN. You want radial or some other remote cup design. Otherwise when you flop the pump the fluid falls out. Here's a random example of a Nissin pump:
https://www.ebay.com/itm/09-Suzuki-GSXR-GSX-R-600-GSXR600-front-brake-master-cylinder/272760980762?hash=item3f81d2451a:g:lc8AAOSwY4pZZ4Hb&vxp=mtr
With some combination of these and a day's effort, you should be able to make the hydraulic ratio for your favorite stroke and effort. It will take someone with more knowledge of hydraulics than I have to sort out the best theoretical sizes. Clutches differ from brakes as far as what the slave cylinder is doing.
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I just did a quick measurement of our three small yamaha 150cc bikes here in bali.
My own bike, the oldest of the three which has covered a mere 115000km has a clutch pull of 30 lbs which drops to around 22lbs when the clutch is fully pulled in. I guess a good lubrication of lever and cable is in order.
My wifes bike has a clutch pull of 18 lbs. also some lubrication is in order.
The last bike belongs to one of my friends and is the newest one with the least kilometeres on it. That is around 10-12Lbs.
My Guzzis I don't know, but will try to see what I come up with when I have finished the new hydraulic clutch cylinder. And then cross check with my friends G5 with normal cable clutch.
-Ulrik
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http://www.benchmarkworks.com/articles/howto/clutch.html (http://www.benchmarkworks.com/articles/howto/clutch.html)
(http://www.benchmarkworks.com/articles/howto/clutch_files/clutch1.jpg)
I'm thinking about putting one of these on my R75/5. If I get one, I'll try it on the Eldorado first, and get a second one for the BMW if it fits the Eldo.
I put one of those on my buddy Leo's R75/6. He liked the reduced effort, but not the abrupt engagement.
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I just did a quick measurement of our three small yamaha 150cc bikes here in bali.
My own bike, the oldest of the three which has covered a mere 115000km has a clutch pull of 30 lbs which drops to around 22lbs when the clutch is fully pulled in. I guess a good lubrication of lever and cable is in order.
After a quick lubing and adjusting the alignment of the cable to clutch arm, the pull effort is now down to average 16lbs to pull the clutch and it tops around 20lbs when it sticks a bit. Effort to hold it in once pulled is down to around 10lbs. So the lubing was well worth the effort!
-Ulrik
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I put one of those on my buddy Leo's R75/6. He liked the reduced effort, but not the abrupt engagement.
I would think that the friction zone should require double the lever movement, making it less abrupt.
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I would think that the friction zone should require double the lever movement, making it less abrupt.
All I know is the result: before: very progressive engagement, after: nearly on/off.
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Very interesting topic! I never thought of measuring clutch pull but will check mine tomorrow. Seems like a good way to check up on maintenance issues. I do know the 87 LeMans has a pretty strong pull, and I've already replaced the clutch lever bushing at the handlebar. Routing the cable with smooth wide bends also helps. I don't have a problem with it as it is, but it is noticeably stiffer than the airheads.
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A friend had a Stone that he kept going through cables on. When a couple of us went over there to put a new cable on his bike just before he was leaving for a trip, I discovered the pull was abnormally hard. Upon inspection, the pivot pin on the arm on back of the transmission was binding. We got it moving freely and Bob mentioned it had never been that easy even since new.
Something worth keeping an eye on for you guys. Just remember to pay attention to where the return spring came from. If you look at it, it looks like it might go somewhere that it really does not belong. So, look before you disassemble to clean and lube. That way, you know where the spring actually belongs.
John Henry
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All I know is the result: before: very progressive engagement, after: nearly on/off.
This surprises me too. Here's what the benchmarkbmw site claims:
"The clutch pressure required will be cut in half and the engagement range of the lever will be doubled. Your clutch will no longer act like an off-on switch."