Barnett Commando friction plates

Why do Barnett include with each kit instructions to soak the plates in oil before using them when all Dominator and Commando clutches were designed to be run dry if they are not to suffer from slip problems IF an owner actually applies a tad of torque to them......?? Are Barnett using a friction material only suitable for use in clutches designed to run in oil? Have Barnett ASSUMED that because Norton etc clutches are employed within the oil bath chain case that the clutches must be designed to run with oil on the friction interfaces??

Why don't you ask Barnet?

dont really care as long as they work perfectly and they do so why worry about it ??

I assembled my Barnett plates, (new friction and plain) in my Atlas DRY, then left the clutch with spring pressure applied for several months while I attended other issues. When I went to free up the clutch, I found it impossible to do. I had to disassemble the clutch, and remove the plates. Three pairs of plates were so stuck together, I had to wedge a pointed tool between them to get them separated.

Reassembled with a smear of ATF on the plates, left with spring pressure several more weeks, no problem.

I agree the clutches (both Commando and pre Commando types) were designed to run dry. However, they actually run in an oil mist if proper fill levels are observed. I contend, and my experience has proved, the oil mist permeates and wets every part of the clutch, even into the shock absorber center of the Atlas/Dommie clutch.

Barnett most likely is aware of this oil migration tendency, and has provided friction material to cope with it.

Slick

J. M. Leadbeater said:

Why do Barnett include with each kit instructions to soak the plates in oil before using them when all Dominator and Commando clutches were designed to be run dry if they are not to suffer from slip problems IF an owner actually applies a tad of torque to them......??

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How many more times must we endure this? :roll:

Whether the original clutch was designed to be 'dry' or not is basically irrelevant and your continual assertions that these clutches slip under normal use if they get a little drop of oil on them (which they obviously will if any oil at all is used in the chaincase) in my opinion is over-exaggerated.

J. M. Leadbeater said:

Are Barnett using a friction material only suitable for use in clutches designed to run in oil? Have Barnett ASSUMED that because Norton etc clutches are employed within the oil bath chain case that the clutches must be designed to run with oil on the friction interfaces??

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Personally, I don't give a monkey's if the friction material is classified as wet or dry as long as it does the job, not that I have ever used Barnett plates as the standard bronze plates have always proved more than adequate even when the chaincase is overfilled. If Barnett sensibly saw fit to choose a 'wet' friction material for use in a chaincase that would normally contain sufficient oil to 'wet' the plates under normal use then so be it. What is the problem ? :?

texasSlick said:

I assembled my Barnett plates, (new friction and plain) in my Atlas DRY, then left the clutch with spring pressure applied for several months while I attended other issues. When I went to free up the clutch, I found it impossible to do. I had to disassemble the clutch, and remove the plates. Three pairs of plates were so stuck together, I had to wedge a pointed tool between them to get them separated.

Reassembled with a smear of ATF on the plates, left with spring pressure several more weeks, no problem.

Slick

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I had exactly the same experience with my Mercury.

FWIW, the latest Barnett clutch disks use what looks like a carbon/graphite friction material, not the old organic material, and they work extremely well. I just replaced a set of the older style Barnett plates in my grandson's 883 MK3 Commando. We had trouble with the old plates slipping, so replaced them with the bronze originals, and the slippage got worse. I bought a new set from Barnett and installed them, and the slippage is gone. I talked to the tech guy at Barnett for a bit, and he said they had tried a variety of materials over the years (I had asked him specifically about the Kevlar material they tried some years back), and that the current material was the best so far. I didn't think to ask him what the new material actually was, other than that it was some sort of carbon compound. They are the "postage stamp" design, with individual squares of material applied in a fairly narrow circle.

Ken

I have posted about Barnett friction plates numerous times over the years warning to assemble a new set using a light ATF lube.

Twice I ruined new Barnett friction plates and in short order figuring they were the same as regular Norton plates - no lube needed

dry, they rub on the steel driven plates and remove the friction material

I also had a problem with the square centering tangs being worn to little pointed tips, being almost rounded off and spinning in the clutch basket

my guess is they are just not manufactured thick enough in that area

but others report no premature tang wear so who knows

regardless of Barnett's being quite a bit cheaper than standard Andover Norton quality I am going back to stock friction plates when this set of Barnetts' wear out again

I will pay twice as much but from my experiece they last a LOT longer than the Barnetts

My Barnett clutch plates have done over thirty thousand miles with no issues whatsoever. Fitted at the same time as my primary belt drive, Never had oil on them and with the major resto completed recently they were judged perfect for re-use.

Fullauto said:

My Barnett clutch plates have done over thirty thousand miles with no issues whatsoever. Fitted at the same time as my primary belt drive, Never had oil on them and with the major resto completed recently they were judged perfect for re-use.

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It is curious your experience with DRY Barnett plates is so different than mine and lazyeye6. Is it possible Barnett uses different friction material for Commando and pre-Commando clutches?

Slick

This is the latest Barnett clutch instruction sheet.



Makes no mention of whether they consider the Norton clutches wet or dry, so we soaked them in Type F ATF anyhow. Seem to work ok so far, but we've only got a couple thousand miles on them.

Ken

ken here another trick to increase the torque capacity. I will warn you that the steels are hard as woodpecker lips to cut but it can be done as i have shown.

lcrken said:

FWIW, the latest Barnett clutch disks use what looks like a carbon/graphite friction material, not the old organic material, and they work extremely well. I just replaced a set of the older style Barnett plates in my grandson's 883 MK3 Commando. We had trouble with the old plates slipping, so replaced them with the bronze originals, and the slippage got worse. I bought a new set from Barnett and installed them, and the slippage is gone. I talked to the tech guy at Barnett for a bit, and he said they had tried a variety of materials over the years (I had asked him specifically about the Kevlar material they tried some years back), and that the current material was the best so far. I didn't think to ask him what the new material actually was, other than that it was some sort of carbon compound. They are the "postage stamp" design, with individual squares of material applied in a fairly narrow circle.

Ken

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I can tell you what happens if you don't soak them. Back in 1973 I installed a set of Barnetts in my Combat without soaking them. Heck, I don't even think that they recommended soaking them waaay back then. About 15 miles into my first ride I pulled a very hard near redline upshift into 3rd and blew the transmission up. Lesson learned. I still use Barnetts even though my first time with them was a pricey first date.

eskasteve said:

I can tell you what happens if you don't soak them. Back in 1973 I installed a set of Barnetts in my Combat without soaking them. Heck, I don't even think that they recommended soaking them waaay back then. About 15 miles into my first ride I pulled a very hard near redline upshift into 3rd and blew the transmission up. Lesson learned. I still use Barnetts even though my first time with them was a pricey first date.

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How did the clutch plates cause your transmission failure? Too grappy?

The narrow radius plates above, are readily available from AN, and have been for years. If I have not used my MK3 for a while then the first time that ride I put a hand full of power through the clutch it will slip momentarily and then will be fine the rest of the ride, so not really a problem.

I think Mr. DeadhorseBeater needs to purchase a Commando, install some ATF soaked Barnett clutch plates, go riding for 20,000 miles or so then report back to us on the slippage/no slippage topic.

Presoaked Barnett Kevlars here in three bikes, 80,000 miles travelled, no slippage, no grabbiness, full release on all three clutches. Thinking of replacing the plates in the bike with 55,000 clutch miles as those friction plates are getting to be quite worn, although they still work perfectly.

Glen

L.A. B. states that I continuallly over exaggerate the fact that Norton clutches slip with oil on the friction plates.
Ok so let us deal with some FACTS (once again) rather trhan the FICTION many would have us believe.......
A motor cycle multiplate gearbox mounted friction clutch is SUPPOSSED to possess a few BASIC qualities SOME of which are that it should ...............
1. NOT slip when fully engaged, even when hot.
2. free off INSTANTLY without drag whenever required, even when hot.
3. be EASILY operated by the user at all times.
4. possess the lightest rotatig weight reasonably possable.
These qualities are given by Mr Phil Irving in his book Restoring Classic Motorcycles and if you do not know who Phil irving was go don your dunces hat and stand in the corner. They are also given in that American pre WW1 book ' Early Motor-cycles. Construction, Operation, Service. Victor W. Page. and if you ahave not read that at least once in your life.....The clutch designs shown are....no I had better not upset L.A. B.........

DECADES ago I conducted a little clutch survay one Saturday afternoon in Motor Cycle Shop in London amoung a few customers asking them if they would be kind enough to fill in a clutch questionaire for me. It contained 9 questions all requireing a yes / no answer . 7 Norton and 13 Triumph owners kindly completed the survay.
Triumph. 5 x T140. 1 x TR7. 2 x 6T. 1 x T120. 2 x T100. 2 x T90.
Norton 2 x 99. 1 x 650SS. 2 x 750 Commando. 2x 820 Commando.
I will list the questions and the answers given as Triumph YES / NO. Norton YES / NO.
!. Are you happy with your primary system..............................................................10/3...6/1.
Does it suffer from...........
2. Clutch slip due to oil on the plates cured by removing the oil from the plates?.....................4/9...5/2.
3. Clutch drag which requires the clutch to be freed off before starting the bike?....................8/5...5/2.
4. Clutch drag immediately after starting the bike making gear selection 'noisel'?.....................7/6...4/3.
5. Clutch drag when the clutch is hot making gear changing and finding neutral difficult?............9/4...4/3.
6 . An aching left wrist during or after a journey due to heavy clutch lever operation?................7/6...2/5.
IF YOU HAVE ANSWERED YES TO ANY OF THE QUESTIONS ABOVE (2,3,4,5,6) DO YOU ......
7. Regard them as problems which are annoying?.........................................................11/2...6/1.
8. Regard them as problems but which are 'normal'?......................................................12/1...5/2.
9. If you bought a new motor car and had ANY of these clutch problems occure would you
consider them to be normal?..............................................................................0/13...0/7.

I conducted this survay simply to confirm that my British motor cycle clutch experiences were the same as every one elses whilst considering whether or not to get into the belt drive business. The survap merely confirmed my experiences werew 'normal'....trouble is we became so used to these clutch problems over the years we accepted them as 'normal' and with the GREATER majority of owners not even knowing how a clutch SHOULD work....bet it came as a shock when they bought their first car !! I DID NOT get into the dry running diaphragm spring clutch belt drive business ..not for making them for sale to the public anyway but for friends A65s, B50s, B40s, C15 trials,Triumph and Noirton twins, Manx Norton, G50 , 7R and I even converted a 350 Aeromacchi clutch to diaphragm spring (which kept me amused for a few days playing on the drawing board...ended up with half the number of plates and a clutch lever the rider could actually operate AND all without a clutch slip problem....It kept me amused .....

Norton clutches were DESIGNED to be run DRY and NOT with oil on the friction interfaces. Run DRY and the torque capacity within the clutch is such that they will NOT slip even IF max crank torque is shoved through them. Run with oil mist or oil on the friction interfaces and apply anything like a tad of real torque to the clutch and it will slip. Bronze plated 820 clutches slip....the whole point of introducing bronze friction plates was as a LAST attempt by NVT to cure the VERY SERIOUS Commando clutch slip problem they had after having tried to do so by using stronger diaphragm springs that increased the clamp load from approx 380 lbf to approx 550 lbf which of course made clutch lever action a lot heavier.... Villiers also used sintered bronze plates in their earlier Starmaker clutches which were originally designed to be employed DRY Ferodo RYZ or VG for which both data sheets state and I quote 'Thios material is intended solely for use under dry operating conditions.'. I spent 30 odd years picking the brains of the Laycock Chief cClutch Designer, he even dragged out his old design notes book for his Starmaker single and twin friction plate clutch designs for me.....both of which were CORRECTLY designed DRY clutches. The use of sintered bronze was a BODGE just as it was for Commando clutches , a bodge to try to cure a serious clutch sl;ip problem.. Sintered bronze does not glaze and thrives on high temperatures... the THEORY being that when oil enters the clutch causing slip to occur the resultant slip generates rediculously high temperatures within the friction interfaces which burns off the oil causing the slip leaving the clutch in theory dry again..... Go, as I once did, and strip a large pile of ex USA second hand Commando clutches fot any good clutch centres....EVERY bronze clutch plain plate showed signs of seriosly high temperatures and to seperate the plates required a chisel!!. I doubt the average owner even notices their clutch is slipping they are so used to it ........Of course the burnt off oil leaves a black deposit on the plates and clutch drag becomes a problem but if you strip the clutch on a regular basis (10,000 miles?)and wash the plates in what they call petrol these days........Memories of reading the genuine Norton Single and Twin Dommy Maintenance Manuals...Problems Page. Problem-clutch slip. Possible cause- oil on plates usually caused by overfillling chain case . Remedy - Dismantle clutch and wash plates in petrol. In my young days when throttles spent much of their time fully open we often had our plates soaking in a petrol bath!!
As for Commando flywheels or clutches as NVT called them....how on Gods earth do they ever come remotely close to satisfying the requirement that they should possess the LIGHTEST rotating weight reasonably possible ESPECIALLY the bronze plated lumps. They are in my opinion and that of a feww ex NVT people / friends etc resonsible for much of the gearbox wear and failure problems .....Peter Williams did not use them on his race bikes.....he used smaller lighter ones but Peter Williams just like his late Father before him was I suspect fully aware of the qualities a clutch is suppossed to possess...Peter Williams even changed the primary ratio to REDUCE the torque being shoved through the gear cluster that was originally designed in the late 1920s by Sturmy Archer for motors producing a LOT less grunt that a Commando....Thank the gods that in those days people designed things using decent safety factors!!! Exactly why on earth did AMC change the primary ratio on Commandos from the 2 to 1 of the 650SS and Atlas?? It only increased the torque being shoved through the poor old long suffering box....but it was AMC....and the Commando was only intended to be a 2 year stop gap model after all....so we heard ....
Of course one advantage to employing a dry runing belt drive can be a complete clutch that works perfectly with no slip or drag and is easily operated al;l day long but which only weighs about 6 1/2 lb reducing rotating weigh CONSIDERABLY ...If you double the weight you quadruple the rotating weight / mass..some(much?) of it unbalanced which does the gearbox little good?....Ever compared the static weight of various Norton clutches? It is amusing! I firmly belive the BSA / Triumph / Norton factories had a yearly competition to see who could fit the heaviest clutch.....I think Norton eventually won outright with the 820 lump but I never weighed one from a 3 although a friend made much of his living reducing their weight for his customers.Bet they were designed by a car clutch designer who assumed they were to be bolted to the flywheel but that is another tale of Triumph incompetence.
But at the end of the day if you are happy running around with a bronze plated Commando clutch on the end of your main shaft so far away from the sleeve gear main bearingthen be my guest because I dont care... Peter Williams did care because a gearbox failing can lock up the rear wheel .....as a few works Commando riders I believe found out riding around The Island!! Hopefully whilst going in a straight line and just before reaching a pub.......So how far did you get lasat night in practice before the gearbox failed? WHAT you made it to Ramsey!! Bloody hell I only made it to The Highlander / Ballacraine/ Kirk Michael . Ballaugh..........there being pubs at all such places although not now alas........I understand The Manx Arms in Onchan is still open....on the olde Clypse circuit of my younger days watching TTs.....I was in shorts and on orangeade in those days and in shorts....
Norton clutches were DESIGNED to be employed DSRY and will slip with oil or oil mist on the friction interfaces IF AND I REPEAT IF an owner applies lots of available engine torque to the clutch and to prove it some .MORE FACTS......... 750 Commando. Playing at being in the D.O. and having been given the job of BODGING the earlier Starmaker twin friction plate clutch for the proposed two year stop gap Atlas Mark 3 modelas the old AMC Atlas clutch was such a ******* to operate ...they even tried a triplex chain version on an Atlas AMC clutch.....bet that worked well!!....SOME VERY SIMPLE BASIC back of fag packet calculations .......
1..Required clutch torque capacity. Max crank torque 48 ft lb. Primary ration 26t-57t sprockets. MAX torque at clutch = 105 ft lb. Rule of thumb clutch service/safety factor = x 2. Required clutch torque capacity = 240 ft lb.
2. What we ended up with..IN THEORY. 4 friction plates = 8 friction interfaces. Effective radius of friction interfaces = approx 0.21 feet. Clamp load being applied by a CORRECTLY set up 0.075 inch thick original diaphragm spring approx 380 pounds force according to the Norton test results.and my testing. Friction material shown on the Norton drawings is Ferodo MS6. The Ferodo MS6 data sheet gives coefficient of friction values to be employed for design purposes as DRY 0.34. OIL MIST 0.1-0.12. SWIMMING IN OIL 0.09. Thus the IN THEORY torque capacity of the original Commando clutch is ............
DRY ...................................8 x 0.21 x 380 x 0.34 = 217 ft lb.
OIL MIST...............................8 x 0.21 x 380 x 0.12 = 77 ft lb.
SWIMMING IN OIL.....................8 x 0.21 x 380 x 0.09 = 56 ft lb.
With a required clutch torque capacity of 210 ft lb then CLEARLY the 750 Commando clutch was a CORRECTLY designed DRY clutch that will suffer slip problems IF an owner shoves a bit of torque through the clutch when oil has reached the friction interfaces!!
In answer to the question why dont I ask Barnett.....clearly you have NEVER tried.....A FAX sent to QPD in the USA by Barnett dated MAY 15 2014 shows a page taken from a friction material suppliuers catalogue. It shows 9 different materials one being hand marked CARBON and the other KEVLAR. The page is headed WET FRICTION APPLICATION CHART (CONTINUED). The coeffifient of friction values shown are as follows CARBON Dynamic 0.12-0.15. Static 0.12- 0.17 and for the one marked KEVLAR Dynamic 0.12-0.15 Static 0.10-0.15. At NO POINT does it state that the materials are suitable for DRY use.The Kelvar one shown as suitable for European automative clutches and the Carbon as being suitable for Automotive shifting clutches.
IN A FAILED ATTEMPT to obtain details of the DRY friction materials Barnett could fit to Bob Oswalds QPD dry belt systems clutch plates Bob asked for the data sheets to be supplied.....Barnett sent him EXACTLY the same sheet but removed DRY from the heading.......Clearly Barnett thought Bob Oswald a brain dead who would not notice....I noticed as i printed off the attachments..... Of course it could be that Barnett think any clutch enclosed within an oil bath chain case must be designed to be employed with oil on the friction interfaces.......Clearly they never spoke to Bert Hopwood or Doug Hele.....
TO finish . Many years ago I described the bronze plated Commando clutch to The Laycock Engineering Chief Clutch Designer / Engineering Director......I heard his calculator being attacked.....he came back to me saying 'But surely the clutch suffers from slip due to oil etering the friction interfaces through the open bearing and the slots in the diaphragm spring?' I replied 'GOT IT IN ONE'. I learnt a few years later that instead of using the 550 lbf clamp load of the spring used in the 820 clutch he had used the 800 lbf of one of the two springs he designed for the Startmaker clutches....(the other applied 740 lbf).
For those who want to play 820- clutch.... .....The 0.084 inch thick spring fitted to the later 820 Commandos applied a clamp load of approx 550 pounds force. The rule of thumb coefficient of friction for sitered bronze are DRY 0.3...WET 0.06-0.08 and the Laycock Engineering Gent employed 0.06 for ALL his many wet bronze clutch calculations throughout his working life stating to me that to use 0.08 was beinga bit optimistic!
Funny little calculation to amuse. 820 clutch. Required clutch torque capacity 240 ft lb.
5 friction plates = 10 interfaces. Effective radius 0.21 ft DRY c of f = 0.03. ASSUMING Norton never changed the diaphragm spring drawing showing the clamp load was now approx 550 lbf and it still showed it as the original testing had shown of 380 lbf.....look what happens if the clutch were run dry with a nice two finger operated diaphragm spring.......
DRY...10 x 0.21 x 0.3 x 380 = 239.4 ft lb making the bronxe plated vastly over weight lump / clutch a CORRECTLY designed (TORQUE CAPACITY WISE ONLY) DRY clutch!!
So you know what to do...fit a dry running belt and ru it DRY but if you continue to use that rediculously over weight lump on the end of that main shaft I consider you totally MAD. But thats your choic and if like most British bike owners I very occasionally see on the roads these days you only poodle around in an effort to preserve engine and gearbox life......
Having noted the twin engined motors that some have played with shown onn these web pages they would have noproblem finding a clutch suitable torque capacity wise...a std DRY bronxe plated 820 lump........
10 x 0.21 x 550 lbf x 0.3 = 346 ft lb.....working backwards..... x 2 safety factor = 173 ft lb at clutch .....2 to 1 primary ration + 86 ftr lb at crank......best to fit hydraulic clutch lever operation ......just like a friend is doing to yet another rotary Norton at present and for the same reason!!

So you know what to do...fit a dry running belt and ru it DRY but if you continue to use that rediculously over weight lump on the end of that main shaft I consider you totally MAD. But thats your choic and if like most British bike owners I very occasionally see on the roads these days you only poodle around in an effort to preserve engine and gearbox life....

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so what is the alternative to NOT continuing to use the over weight lump on the end of the main shaft in order to avoid you considering me totally MAD?

or did I miss your redesigned light weight engineering design suggestion somewhere in your post, sir?

and if so please tell me where I can buy this, do you have a web site and how much money to replace my stock commando clutch?

J. M. Leadbeater said:

L.A. B. states that I continuallly over exaggerate the fact that Norton clutches slip with oil on the friction plates.

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I still do.

J. M. Leadbeater said:

if you do not know who Phil irving was go don your dunces hat and stand in the corner. They are also given in that American pre WW1 book ' Early Motor-cycles. Construction, Operation, Service. Victor W. Page. and if you ahave not read that at least once in your life.

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Just because a person may not have read or heard of Phil Irving or hasn't read some other obscure technical paper from 'way-back-when' doesn't make anyone stupid, it just shows how out of touch you are with reality!

J. M. Leadbeater said:

I had better not upset L.A. B.........

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Irritate rather than upset and I doubt it's only me as you repeat the same ancient info. over and over again in your customary disagreeable manner with the usual insults thrown in for good measure that you were doing on BriBike and elsewhere (as BDM) over 10 years ago which usually ended up with you getting kicked off, and I think the same thing is going to happen here shortly.

J. M. Leadbeater said:

DECADES ago..I conducted a little clutch survay one Saturday afternoon in Motor Cycle Shop in London

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Yes, everything with you is "decades ago" isn't it? Highly scientific survey, that.

J. M. Leadbeater said:

Norton clutches were DESIGNED to be run DRY and NOT with oil on the friction interfaces.

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There you go repeating yourself again. So I shall have to repeat that it's basically irrelevant.

I think I should point out that there is no such thing as "over exaggeration."

It's "exaggeration."