Hard to Pull Clutch - Ideas? (2011)
- Thread starter Bonwit
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The diaphragm spring clutch on the Commando was one of the best features of the bike. The operting force was about 1/10 of that needed to pull the clutch on the 650SS or the Atlas.
If you can't pull the lever all the way through its travel with about 3 to 4 pounds of force, something is seriously amiss. Note that we had some very clever Bowden cables on the Commando. See an earlier post of mine about getting the cables from a farm in Dorset!
If you can't pull the lever all the way through its travel with about 3 to 4 pounds of force, something is seriously amiss. Note that we had some very clever Bowden cables on the Commando. See an earlier post of mine about getting the cables from a farm in Dorset!
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My idea is how about you ride the bike more often and build up some muscles in your left hand and wrist?
Though I am right handed, during riding season I could always peg those machines at arcades and fairs that tested your grip with my left hand, never my right. Thank you Norton! In the off season during winter, use your left hand when tossing off to keep in some sort of condition for the spring.
Though I am right handed, during riding season I could always peg those machines at arcades and fairs that tested your grip with my left hand, never my right. Thank you Norton! In the off season during winter, use your left hand when tossing off to keep in some sort of condition for the spring.
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Hard to pull clutch
1974 commando 850
I am happy to say that Matt is a genius at Colorado Norton Works, I purchased the easy pull clutch set up with the extra seal, installed it myself and couldn't believe the difference, it's a whole new riding experience and the joy of shifting is back, It feels like a hydraulic clutch.
I spoke to Matt on the phone, he was very insightful and helpful and it was the best money I spent on this bike, i hope this helps others to know there is a solution to a 2 finger pull.
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I never saw the need for a hydraulic set up on a Commando, it is unnecessary complications and clutters up the handlebars. I wish there was the same clutch for Triumphs.
NOW, the latest rabbit from AN is not as good as an old rabbit from an Atlas? If so, why hasn't AN gone to the better profile?
NOW, the latest rabbit from AN is not as good as an old rabbit from an Atlas? If so, why hasn't AN gone to the better profile?
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There's no reason for AN to go to the Atlas profile lifter as it is intended to be used with a clutch that operates differently and with a 7/8" pivot radius handlebar lever (explained in the link, below). Fitting an Atlas lifter might result in a lighter action but at the expense of reduced clutch lift.
If the Commando stack height is adjusted correctly then the clutch can be light without loss of lift.
"11. THE CLUTCH LIFT MECHANISM"
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BDM " 11. THE CLUTCH LIFT MECHANISM In his web page ‘Dyno Dave’ states, and I quote, ‘The Atlas actuator cam certainly has more than adequate lifting range for a Commando clutch, and in fact the Commando actuator cam gives more than double the lift needed to completely disengage the clutch. This makes the ROD / cam ball free play adjustment of little concern in actual use, with the Commando actuator arm’. A couple of points possibly worth mentioning….. 1 The Commando clutch actuating cam (clutch operating lever 06-0715 in the parts books) and the earlier Atlas / AMC one (04-0029) both give very similar lift at the clutch for the same amount of clutch operating lever CABLE movement
I once did some testing. NOT laboratory type where measuring of the movement of handlebar lever and clutch operating lever would be taken to determine exactly what was happening but close enough for my needs at the time."
dd: really? My test "WAS" with measurement test equipment. .5" cable travel yielded .088"atlas vs .131"commando lift. very similar???
After BDM further opinion only rambling backed up with "I was told" source for his "whilst giving the same total clutch lift " statement
How many folks would work for a very similar paycheck? 67.175% of your pay?
Bang on the keyboard and pump out all the words you want, but I pity those who don't believe science, math and measured physics.
This was the results from 23 1/2 years ago which should be able to be repeated with the same results today:
How ever since those days, I had discovered the manufactured lever consistency of old original levers, including ANIL new levers do vary measurably from each other.
ANIL lever may be manufactured more consistent but are not identical to old levers.
I once did some testing. NOT laboratory type where measuring of the movement of handlebar lever and clutch operating lever would be taken to determine exactly what was happening but close enough for my needs at the time."
dd: really? My test "WAS" with measurement test equipment. .5" cable travel yielded .088"atlas vs .131"commando lift. very similar???
After BDM further opinion only rambling backed up with "I was told" source for his "whilst giving the same total clutch lift " statement
How many folks would work for a very similar paycheck? 67.175% of your pay?
Bang on the keyboard and pump out all the words you want, but I pity those who don't believe science, math and measured physics.
This was the results from 23 1/2 years ago which should be able to be repeated with the same results today:
How ever since those days, I had discovered the manufactured lever consistency of old original levers, including ANIL new levers do vary measurably from each other.
ANIL lever may be manufactured more consistent but are not identical to old levers.
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Was that measured on one of your test rigs or a working Commando clutch as my Commando's clutch, when set to 0.130" 'carrier' lift, doesn't even begin to free off (pressure applied to the kickstart lever) until 0.070" so the spring fingers can't be totally "free and clear" even at that stage but only lifted sufficiently for the clamping force to be removed from the pressure plate and that's without any additional plate interface lift required for a drag-free clutch as BDM mentions in which case my Commando's actuating lever can't be providing "more than double the lift needed" to fully disengage the clutch.
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My only test fixture was for measuring the diaphragm spring deflection rate. It consisted of an empty clutch basket with the diaphragm inverted in it. This sat on my bathroom scales in my 25 ton hydraulic press. Dial indicator, clamped to the press ram, measuring to the clutch basket. Pounds indicated on the scales and spring deflection measured on dial indicator.
Data taken: pounds/deflection in inches
The release measurement was done on my regular driver combat with a dry belt drive. Normal solid fiber plates and CCRS to keep the goo from glueing the plates together, which I would guess, would drastically increase clutch drag, especially if "cold" 90w & primary oil on them. With the primary cover off I clamp the dial indicator to the primary case inner and put the dial indicator on the center carrier. I very lightly zeroed the cable and cam slack/free play (adjuster nut) before carrier lift measurement.
Since the stack height pressure was adjusted, the finger pressure would, as expected, be light to affect release. Therefore NOT requiring a lot of finger bend resulting in a small lift measurement affect release. A stiff clutch would require more finger bend (deflection) to obtain release.
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Well, that might just have been worth a mention (at some point during the last 23 1/2 years?).
A 4-friction plate DRY belt drive clutch probably wouldn't need as much lift as the standard oil-contaminated 5 (or 4) friction plate clutch, therefore, I'm glad I did "bang on the keyboard" or that piece of information might never have come to light.
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Mainly refering to BDM...super long article.
From my article:
"Regardless of the reason for slipping, the results are all to real to the owner/rider and therefore making the dry clutch design argument a rather moot point. "
"By .050" lift both sets of fingers are free and clear of the clutch pressure plate and the clutch should have almost no engaging properties."
However remember his assertion that this is designed as a DRY clutch. So why can't I do testing with a dry clutch? The clutch plates are released from pulling torque due to plate compression but residual gear and primary oil contamination provide sticky drag. With my CCRS I went 5 years with my MKIII before a cleaning was needed.
The whole point of my article was to mitigate the problems of a commando clutch apparently over 6000 CCRS owners were convinced...why am I now the bad guy?
From my article:
"Regardless of the reason for slipping, the results are all to real to the owner/rider and therefore making the dry clutch design argument a rather moot point. "
"By .050" lift both sets of fingers are free and clear of the clutch pressure plate and the clutch should have almost no engaging properties."
However remember his assertion that this is designed as a DRY clutch. So why can't I do testing with a dry clutch? The clutch plates are released from pulling torque due to plate compression but residual gear and primary oil contamination provide sticky drag. With my CCRS I went 5 years with my MKIII before a cleaning was needed.
The whole point of my article was to mitigate the problems of a commando clutch apparently over 6000 CCRS owners were convinced...why am I now the bad guy?
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The next time I remove the primary cover I will check the finger lift but my own clutch not slipping until 0.070" seems to suggest the fingers are not clear of the pressure plate by 0.070".
Yes, "designed" but in several places makes it absolutely clear that the clutch doesn't operate in a dry environment (Section 5. DRY AND WET CLUTCHES, TORQUE AND OIL. for instance).
No reason whatsoever but I think you also agree that the standard Commando clutch can't be regarded as a totally 'dry' clutch regardless of how it is described.
Yes, and I'm one of those owners but only reinforces the fact that the presence of oil on the plates can't simply be disregarded.
I wouldn't say that but for anyone interested in the workings of the Commando clutch then the BDM article is definitely worth reading in my opinion.
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Everyone may want to know the .050" clutch center lift I measured represents .025" at the pressure plate contact ring/circle.
And my article mentions it and BDM even acknowledged it in this email to me:
What I said:
I doubt the norton commando factory has ever advertised that the primary with a chain should be run dry. The clutch may have been designed by an outside vendor for dry service, but then the factory would have knowingly installed a dry clutch into a wet application.
How BDM redefines my statement as his fiction?
"Dyno Dave’ (a British bike expert?) appears to believe that Norton would not place a designed to be employed DRY clutch within their OBCCs and tells the World exactly that in his Commando clutch web page"
I have not audited his writings, but it would appear he mainly/only mention OBCC. I don't readily see gearbox mainshaft oil problem as being ever mentioned. A rather significant omission, IMO.
My MKIII still runs primary oil like they all do, but with the CCRS I got 4 seasons of trouble free riding and only in the final year when the original battery finally died the clutch started to act up from primary oil not gearbox oil.
I parked it to run my combat instead .
To this day since 1989 it still runs CCRS sn#1.
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Yes, indeed, and it's something I've banged the keyboard about in previous clutch discussions that unlike a typical British bike clutch where the pushrod directly lifts the pressure plate so all pushrod movement is basically converted into clutch lift, the Commando clutch 'lift' (although the pressure plate isn't actually lifted at all) is only approximately half pushrod/spring lift and the reason for the increased lift of the Commando actuator as the spring has to be moved twice the clutch lift distance. The BDM article mentions this significant difference in clutch operation but I don't think you mention it in your clutch lift info?
No, obviously not.
We don't know what the factory thinking was but can only assume they were satisfied with the clutch at the time the Commando was introduced.
It is unfortunate that he repeatedly singled you out for criticism but if BDM's grip calculations are accurate, which I expect they are, then it does indicate that the Commando's clutch was borderline when used in an oil-bath chaincase as his article is basically a critical analysis highlighting the shortcomings of the Commando clutch.
He does mention it in section 19, page 54, but puts it down to overfilling of the gearbox. Other members here have said their clutches don't suffer from the gearbox oil migration problem so seems not to affect all Commando clutches.
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"Please note the chart shows pressure at the clutch center and therefore the pressure on the clutch stack would be approximately double."
also
overfill or oil climbs?
OK BDM spent weeks if not months researching his topics including aid from "university friend", MC industry and norton factory buddies .
Hopefully a hour test in my basement and maybe a little more doing 2 excel graphs with a write up got folks off the coil spring clutch mind set. Just me and a 72 and 75 commando and a few shop tools and equipment .
Some dealers knowingly sell my clutch rod seals to benefit their customers... to save them money. The strange thing is some dealers refused to sell my clutch rod seals. Simple they won't make repeat busine$$, and more money $elling clutch plate$. again and again and again.
A clutch rod seal and an extra clutch plate ?? $30.
Think I'll go work on my Lotus Elan
also
overfill or oil climbs?
OK BDM spent weeks if not months researching his topics including aid from "university friend", MC industry and norton factory buddies .
Hopefully a hour test in my basement and maybe a little more doing 2 excel graphs with a write up got folks off the coil spring clutch mind set. Just me and a 72 and 75 commando and a few shop tools and equipment .
Some dealers knowingly sell my clutch rod seals to benefit their customers... to save them money. The strange thing is some dealers refused to sell my clutch rod seals. Simple they won't make repeat busine$$, and more money $elling clutch plate$. again and again and again.
A clutch rod seal and an extra clutch plate ?? $30.
Think I'll go work on my Lotus Elan
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No explanation why it doubles or, as I said, any mention of the clutch lift being halved at the pressure plate which perhaps would've given "folks" a better understanding of how the clutch works but that's just an opinion.
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"Please note the chart shows pressure at the clutch center and therefore the pressure on the clutch stack would be approximately double."
The thrust measured is from the bellville washer, that IS the diaphragm thrusting force. The stationary force origin is the outer rim held by the circlip.
The thrust is applied, to the pressure plate thrust circle, just inside of the cut circles on the diaphragm. This defines the inner end/rim of the bellvile spring.
The release arms extend bellville washer physical connection inward to connect inside the release body. The length of the arms are about equal to the rim to belville Inside diameter. This gives the release arms 2x mechanical leverage on the spring.
My chart shows lever force therefore the spring force (applied to the pressure plate ring) is twice the chart indication.
I had perceived this as 9th grade physics?
I did get an A in 9th grade physics, and a C in everything else.
For some lite reading I found the hassermann article interesting, and maybe more exacting description..
IIRC you must now "sign up/register" to see this article from their site but I had previously copied it 13 years ago.
The thrust measured is from the bellville washer, that IS the diaphragm thrusting force. The stationary force origin is the outer rim held by the circlip.
The thrust is applied, to the pressure plate thrust circle, just inside of the cut circles on the diaphragm. This defines the inner end/rim of the bellvile spring.
The release arms extend bellville washer physical connection inward to connect inside the release body. The length of the arms are about equal to the rim to belville Inside diameter. This gives the release arms 2x mechanical leverage on the spring.
My chart shows lever force therefore the spring force (applied to the pressure plate ring) is twice the chart indication.
I had perceived this as 9th grade physics?
I did get an A in 9th grade physics, and a C in everything else.
For some lite reading I found the hassermann article interesting, and maybe more exacting description..
IIRC you must now "sign up/register" to see this article from their site but I had previously copied it 13 years ago.
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But still no mention of 'lift'.
Well, good for you, but this is the problem with technical writing as the author takes it for granted that readers have the same level of knowledge or expertise which is often not the case (or they probably wouldn't be reading it).
As an example, I had to look-up what "9th grade" was.
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dynodave = Hamilton Mass USA
USA has high school to 12th grade
Junior high or middle school 6-8 grade I was 12-13 in 8th grade
Lift comes from a magic external device some how connected to the handle bars. (this is called sarcasm)
Subject however is discussed ad nauseaum else where ... like posts 1-47 of this thread, please review for a refresher.
Even BDM goes over it...in an unscientific way "NOT laboratory type" pg 30 of his article.
And the hasserman article.
If you ask me how to make bread....am I supposed to tell you how to grow wheat and ferment yeast too?
USA has high school to 12th grade
Junior high or middle school 6-8 grade I was 12-13 in 8th grade
Lift comes from a magic external device some how connected to the handle bars. (this is called sarcasm)
Subject however is discussed ad nauseaum else where ... like posts 1-47 of this thread, please review for a refresher.
Even BDM goes over it...in an unscientific way "NOT laboratory type" pg 30 of his article.
And the hasserman article.
If you ask me how to make bread....am I supposed to tell you how to grow wheat and ferment yeast too?
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