Author Topic: Clutching at straws?  (Read 1231 times)

Online a101960

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Clutching at straws?
« on: 04.07. 2018 16:00 »
4 spring clutch (surflex plates) I have posted about the problem of what seems to be clutch drag after the transmission has warmed up before, but I am getting no where. Tried all kinds of things to resolve it with out any success. However, looking at the parts book I notice that it shows a friction plate as being the first plate, that is to say the first plate in the chain wheel,  (see picture). My clutch was assembled with a plain plate in this position. Is that correct, or should the plates be assembled in the order shown in the parts illustration? I have double checked everything. No burrs, or nasty nicks, and plates show no sign of warping. Fitted new springs cups and adjusters. SRM Ally pressure plate and radial bearing. To be honest don't no where to go next. All I know is once everything gets warm Neutral goes missing!

Online JulianS

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Re: Clutching at straws?
« Reply #1 on: 04.07. 2018 16:12 »
Plain plate first.

That diagram not too helpful.

Below from owners manual.

Online a101960

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Re: Clutching at straws?
« Reply #2 on: 04.07. 2018 16:38 »
Quote
Plain plate first.
Parts book illustration as you say not helpful. I have been reading everything I can about these clutches, and just to muddy the waters Draganfly state that the number of plates varies can anyone shed any light on this? I have 5 friction plates and 6 steel plates.

Offline A10 JWO

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Re: Clutching at straws?
« Reply #3 on: 04.07. 2018 17:34 »
I have read that friction plate goes on first on A65's, so why different on A Series ?

Online JulianS

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Re: Clutching at straws?
« Reply #4 on: 04.07. 2018 17:42 »
A65 up to 1965 have plain plate first 5 boned plates. Different design clutch from 1966. The drum does not have a lip as A10 4 spring and bonded plate bears on the chainwheel and it has 6 bonded plates.

Standard setup is 5 bonded 6 plain.

Some bikes were converted from 6 to 4 spring using the clutch parts from the Triumph 500 pre unit dynamo models. The drum was different in that it was designed to take only 4 bonded and 5 plain plates.

Offline A10 JWO

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Re: Clutching at straws?
« Reply #5 on: 04.07. 2018 17:48 »
Well done Julian, a font  *smile*

Offline scotty

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Re: Clutching at straws?
« Reply #6 on: 04.07. 2018 17:53 »
On my 4 spring I have 5 friction plates and 6 plain steel plates with a plain steel plate fitted first in the clutch drum

Scotty

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Online a101960

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Re: Clutching at straws?
« Reply #7 on: 04.07. 2018 18:29 »
Quote
On my 4 spring I have 5 friction plates and 6 plain steel plates with a plain steel plate fitted first in the clutch drum
That is exactly what I have got. What I can't get to the bottom of though is why it drags when it's hot. Gearbox gets a bit notchy at that point too and finding neutral becomes impossible. Both gearbox and clutch operate perfectly until then. This is the third time I have had it all apart and I can see nothing amiss. Clearly something must be wrong. I'll try oil instead of ATF this time, but I won't be holding my breath. Thank you everyone for your comments. Mean while I'm still tearing my hair out.

Offline RogerSB

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Re: Clutching at straws?
« Reply #8 on: 04.07. 2018 19:08 »
Last year I fitted the complete SRM clutch upgrade kit to my 1960 A10 GF and the instructions clearly stated plain plate first followed by friction and so on until all are used up - and there were 6 plain and 5 friction plates in the kit.

I also made myself up an assembly note for future reference. The illustration showing the assembly order is mine (so I hope I've got it correct) but the text is based on SRMs. I've made a picture file of it to attached here - if any help.

1960 Golden Flash

Online chaterlea25

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Re: Clutching at straws?
« Reply #9 on: 04.07. 2018 19:12 »
Hi All,
I would try gently heating the plain plates in an oven, start as low as the oven will go, 60-70 degC
take out the plates carefully and see if any have warped, then try maybe 90-100degC if they remained flat

Does the clutch lever go slack when the clutch gets hot? that would be a symptom of warping plates
A friend had a similar problem with one of his bikes, it turned out an adjuster was vibrating loose *lol*

The A10 setup with the plain plate in first is "a not too clever " idea !!
The spring pressure is acting against the plain back plate at a greater diameter than where it sits on the lip
tending to bow the plate
The clutch can be modified to the later A65 & Triumph setup, as I wrote up in this post
https://www.a7a10.net/forum/index.php?topic=9646.msg70166#msg70166

Last but not least  *ex*
Does your clutch have a solid or cush type inner drum?
Wear in the clutch cush drive components will cause slip or drag problems even though the unit looks perfect externally *warn* *problem*

John

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1963 RGS (ongoing)

Offline DuncanF

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Re: Clutching at straws?
« Reply #10 on: 04.07. 2018 20:18 »
Silly question, but are you SURE the clutch is disengaging squarely? I was sure mine was, but suffered the same grief. It was only when I put a dial test indicator on a stud and plate fixed to the primary case, that I found it wasn't. I mounted the indicator, and rested the end on the pressure plate with the clutch disengaged, then turned the engine over slowly. I had about 1/16" -1/8th" overall discrepancy. When I adjusted the spring adjusters one at a time, and confirmed it was spot-on square, was I happy. When the clutch gets hot and the plates swell, 1/8" is a lot. Voila, problem disappeared.

Online KiwiGF

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Re: Clutching at straws?
« Reply #11 on: 04.07. 2018 23:01 »
4 spring clutch (surflex plates) I have posted about the problem of what seems to be clutch drag after the transmission has warmed up before, but I am getting no where. Tried all kinds of things to resolve it with out any success. However, looking at the parts book I notice that it shows a friction plate as being the first plate, that is to say the first plate in the chain wheel,  (see picture). My clutch was assembled with a plain plate in this position. Is that correct, or should the plates be assembled in the order shown in the parts illustration? I have double checked everything. No burrs, or nasty nicks, and plates show no sign of warping. Fitted new springs cups and adjusters. SRM Ally pressure plate and radial bearing. To be honest don't no where to go next. All I know is once everything gets warm Neutral goes missing!

I’ve no experience of the 4 spring clutch, but on a 6 spring the first plate is plain because the chainwheel has friction inserts in it, which effectively makes it the first “bonded/lined” plate. Having said that one can get odd mixes of parts with clutches and someone could fit plates in the wrong order deliberately, to overcome another problem, such as weak springs.

I assume you have not got the cheap “thin” plain plates, these don’t work well at all but unfortunately are in the aftermarket, supplied by the less reputable suppliers I guess.

It’s not uncommon for a clutch to be ok cold and drag when hot. This can often be fixed by adjusting the springs so the pressure plate lifts off “equally” (eg the same amount) at 4 points at 90deg. There is a bit of an art to this. It’s also important to have the minimum spring pressure such that you dont get clutch drag, but get maximum pressure plate movement. It’s surprising how much overly tightened springs can affect pressure plate movement. It seems the extra force to move the plate causes the cable to “compress” and the various levers take up more slack, resulting in less movement. I get about 080” movement on my 6 spring, but with over tight springs this would reduce to more like 050”.

Are the springs adjustable? If so, are you using a dial gauge to adjust the springs?
New Zealand

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Offline Colsbeeza

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Re: Clutching at straws?
« Reply #12 on: 05.07. 2018 00:18 »
I have just replaced my entire 4-spring clutch (the one without cush), including a new Inner drum. Built up from parts sourced all-over. Not an SRM clutch though. The missus is still speaking, but she hasn't added it all up yet. When she does, I may be looking for accommodation elsewhere.
My new Clutch Wheel as well as the old one has the rivets slightly exposed, and not all evenly. There is no way a friction plate could engage that. I was going to grind them back but decided not to once I thought about it. *conf2* There would be no point in having friction pads on both sides of the first plate. However, having said that, a first friction plate would revolve with the chain wheel, so no rubbing would occur anyway. So I fitted a plain plate first as per the manual.
The Inner drum has the "stops" at the back, so it appears to be designed to prevent the first plain plate contacting the rivets on the chainwheel.
I agree that it was designed to have a plain plate first, but not a great design. As John suggested the pressure plate pushes on the outside of the outer plate, but transfers the forces onto the inner edges of the first plate - could cause buckling of the first plate.! The first plain plate first just clears the rivets sufficiently I hope. The new plates are thick (2mm), so hoping all will be well heat-wise.
I have also replaced the old steel pressure plate with a machined alloy one (I think made by MCA). With such a smooth surface, it was possible to get the plate balanced to +/- 10 thou with a dial gauge although it took about an hour. You may notice that one of the bolts is not visible. That's because it is black. I lost one and the replacement was different.
I am so confident that I have fitted the Clutch Outer Alloy Cover. Be riding it next week with luck.
Colin
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Offline duTch

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Re: Clutching at straws?
« Reply #13 on: 05.07. 2018 03:20 »

 I've had no experience with the 4 Spring ones, and it may be irrelevant but they seem to have similarities to the Plunger 6 Springer which has a thicker plate at the back (I'd be guessing at the thickness though-maybe 2 or 2.5mm as opposed to 1/16" I think for the regular ones )   *dunno*
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Re: Clutching at straws?
« Reply #14 on: 05.07. 2018 08:29 »
Colsbeeza that is exactly how I set my clutch up, and it takes hours to do, or at least it takes me hours. A very frustrating procedure

kiwgf
Quote
I assume you have not got the cheap “thin” plain plates, these don’t work well at all but unfortunately are in the aftermarket, supplied by the less reputable suppliers I guess.
I presume, ( maybe wrongly) that I have good quality plates because the friction plates are surflex and for that reason I believe that good quality parts were used to assemble the clutch in the first place.

I am off to do battle again, I will bear in mind all of your comments and suggestions. I will let you know How I get on.