Author Topic: slipping clutch  (Read 2631 times)

Offline Sam C

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slipping clutch
« on: 17.08. 2015 09:40 »
All

For those that haven't picked this up yet: I'm very new to this. First bike, only learnt to ride a week ago, and bike is about twice as old as I am!

So bear with me.

I'm noticing that the clutch is slipping quite badly, which is a pain. Basically, opening up the throttle too quickly just causes it to slip... which is a bit hairy when trying to overtake anything!

So my questions are:

(1) Is there any sort of adjustment that should / could be made before simply replacing things.

(2) If there isn't / it doesn't work what is it I would replace - on a car I would just buy a clutch kit and fit it - on this bike there seems to be an array of different bits and I can't work out which to buy / what gaskets I'm going to need. Truth be told, until I take the clutch apart I'm not even sure I understand how it works.

(3) Even stupider question: I don't even know what type of clutch I'm likely to have (there seems to be 'four spring' or '6 spring' options... maybe even more?).

(4) Is replacing a clutch / adjusting the clutch a particularly involved or difficult process. I would happily do it on a car, just reading the Haynes, and I have done loads of work on older cars in my time (replacing engines, gearbox, ignition systems, clutches of course etc. etc.). So I am technically okish - a 'competent bodger' is probably a fair description.

(5) Is there anything I should consider from a safety point of view (e.g. some old parts have things like asbestos in them - do I need to worry about anything like that here?).

My bike is a A10 Golden Flash. 1959. 650cc. Swing arm.

Thanks all and apologies for daft questions. Maybe one day I'll be good enough to pass some of this stuff onto someone else that is starting out!

Cheers

Sam





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Online Greybeard

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Re: slipping clutch
« Reply #1 on: 17.08. 2015 09:51 »
First thinks: Is there too much oil in the chaincase? These clutches basically run dry. The small amount of oil in the case is there for the chain.

There should be a small amount of slack, (1/8") in the clutch cable.
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Offline duTch

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Re: slipping clutch
« Reply #2 on: 17.08. 2015 10:14 »
 Hey Sam, settle down and grab a tinnie......Fair chance you have a four spring clutch..maybe..and in your favour.

 They are not difficult, first arm yourself with a sixpack, and a tin can to sit on...and drain the primary case- it can be messy so until you figure out a process, use a fairly sizeable catchtray....when it's fairly drained pull the cover (adding to the "process"), and all will be revealed...

 Now there is different ways you can do it from here; simply proceed with a "clutch spring adjustment", or unscrew all the adjuster screws diagonally and count each turn (not hard/ nor important-but advantageous), and have a look at what you have..also not hard, and a good thing to do....if you can, measure the thickness of the friction plates (the ones with stuff that's not plain steel)

 measure how much oil drained out...not so important (much- just a reference)...and note!
 Grab another six pack...and research "adjusting the clutch", really quite simple and everyone has a variation of it- just something you'll figure out, but don't be afraid to ask...

 I may be back in a few hours *beer*

 G-B's idea noted, but I'm going in deep....

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Started building in about 1977/8 a on average '52 A10 -built from bits 'n pieces never resto intended -maybe 'personalised'
Have a '74 850T Moto Guzzi since '92-best thing I ever bought doesn't need a kickstart 'cos it bump starts sooooooooo(mostly) easy
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Online RichardL

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Re: slipping clutch
« Reply #3 on: 17.08. 2015 17:01 »
GB,

Wouldn't it be more accurate to say that our clutches "basically run wet in a controlled amount of oil"? I can't believe that running anything like dry was planned in the original design. I'm guessing that they ditched the early dome when they realized that didn't keep out the oil anyway, and the clutch still worked fine (for the era). Here is a place where my own limited experience with other motorcycle clutches comes in and leaves me wanting.  It seems to me that the wetness in our clutches provides a degree of smoothness in our takeoffs and downshifts.

Richard L.
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Online Triton Thrasher

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Re: slipping clutch
« Reply #4 on: 17.08. 2015 18:26 »
First adjust the clutch, exactly in the order that the manual says.

If that doesn't fix it, the springs can be tightened, the plates can be washed, or even replaced.


If the four spring clutch is "based on" Triumph clutch types, does anyone know if you can do the modifications to get an extra plate in?
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Online Greybeard

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Re: slipping clutch
« Reply #5 on: 17.08. 2015 18:36 »
...I'm guessing that they ditched the early dome when they realized that didn't keep out the oil anyway, and the clutch still worked fine...

My clutch has the domed cover. I suppose some oil dampness gets in there but not very much at all. You may be correct in saying the oil aids clutch action.
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Offline a101960

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Re: slipping clutch
« Reply #6 on: 17.08. 2015 19:22 »
Quote
First adjust the clutch, exactly in the order that the manual says.
What TT said. That is very important. I have a 4 spring clutch. If you are going to set it up you would be well advised to get yourself a dial gauge. I thought that my clutch operated quite well, but it was difficult to select neutral when stationary. Setting up the clutch plate adjustment with the dial gauge completely transformed the clutch operation. Selecting neutral while stationary is now easy, and the action is light with no drag or slip. You can get a gauge and magnetic stand here for under £20.

http://www.ebay.co.uk/itm/DTI-Dial-Indicator-Gauge-with-Magnetic-Base-Stand-Engineers-Clock-Stand/161019284441?_trksid=p2046732.m2060&_trkparms=aid%3D111000%26algo%3DREC.CURRENT%26ao%3D1%26asc%3D16581%26meid%3D1839658744947729906%26pid%3D100040%26prg%3D7839%26rk%3D1%26rkt%3D4%26sd%3D161019284441%26
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Offline bikerbob

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Re: slipping clutch
« Reply #7 on: 17.08. 2015 19:35 »
If your bike is genuine 1959 and has not been modified then it will have the revised 6 spring clutch fitted, the 4 spring clutch was fitted from 1960. As a start I would check that you have a small amount of play at the handlebar lever also the lever on the top of the gearbox should also have a small amount of play if either has no play then adjust until you have. The gearbox lever is adjusted by removing the small plate on the front of the gearbox inside you will see a nut with a central screw slacken the nut and turn the screw anticlockwise to give a small amount of play. If both have play then you need to remove the primary case and try adjusting the tension on the springs but it is really important that the springs are adjusted evenly as the plate must lift off squarely when you pull in the clutch lever as mentioned in the above post. If that does not cure the slipping then you may have to buy new friction plates.
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Offline oldbeezageezer

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Re: slipping clutch
« Reply #8 on: 17.08. 2015 21:46 »
for what it worth Sam, I have the same bike as you and my clutch was dragging. No amount of fiddling with adjustment made very little difference.
I decided to check the clutch and that's when problems started.

You have to remove the foot rests. Not easy on mine and when I got them off found the splines on left side so worn which explained why the foot brake came on when any weight was put on the foot rest.

Get the foot brake out of the way

Drain the chaincase and remove the cover. You will need to get a new gasket for this for re assembly. General feeling is that silicon gasket goo may break away from the inside of any areas it used on and may block oilways or do other things which won't be good.

My bike had a six spring clutch and the chain wheel could be wobbled from side to side on the shaft. It had to come off which was easy as the lock nut wasn't that tight. The slots in the chain wheel basket where the 'fingers' of the clutch plates slide in and out were worn and burred causing the plates to catch and not operate cleanly.

The cork inserts were almost flush with the pates they were in. You can buy replacement corks and refit them. I suppose someone does that!

The clutch centre was also worn and the large splines that the inner basket slides on were scored and the ends chipped.

I noticed that the inside of the chaincase cover had nice circular scoring where the crankshaft cush drive nut was coming undone. My shaft has an additional 'lock' nut fitted. I have been told by other owners that it is because a split pin had not been fitted so the cush drive nut and the 'lock' nut are trying to escape.

Good news. The chain and main drive wheel do not show bad wear.

I weighed up my options and costed parts for a six spring replacement. A four spring complete replacement clutch was cheaper (£320) so I bought one from a company who assured me it was and would be correct for my bike. After it arrived and I tried fitting it the clutch centre would not go all the way on the shaft and the lock nut would only go on two threads. The taper on the new clutch centre was smaller than my shaft. I called the company and in fairness they offered a refund which I accepted. They then sent me a photo showing the clutch properly seated on a A10 and the lock nut fully secured. 

I then purchased a complete clutch from SRM with their own mods and finer adjustment screw. It is a bit dearer (£385) They also supply a fitting and set up guide, although I did need to clarify some of the wording on this forum. They also give a torque figure for the clutch lock nut which is not in the BSA service sheets or Haynes.

I have today, just finished the adjustments for 'proper' operation. so won't know how good it is until I put everything back together. SRM also do their own cush drive lock nut again with torque setting so I will probably end up getting one of those and replace mine.

You probably won't have the same problems as me but when you do, if you have to replace clutch/parts, don't re fit the chaincase cover until you have tested the clutch on the move. Otherwise its all got to come off again and running without oil in the chaincase won't hurt for testing.

I had an oil leak around the rocker box to cylinder head so thought I would do that while waiting for new clutch. Got it off but couldn't get box back on as the studs would not line up with the holes. Turns out three of them are bent. Waiting for new studs as I write. Should be here tomorrow.

What a101960 said about a dial gauge makes sense to true up the clutch lift and I think I will get one before I finish with the clutch.

Bit of a tale this but forewarned is forearmed as they say. Hope it helps.

As a bit of added info, as this is not enough, I have converted to 12 volt electrics and electronic ignition. I know that works and it starts easy peasy!

Good luck
Alan
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Offline oldbeezageezer

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Re: slipping clutch
« Reply #9 on: 17.08. 2015 21:48 »
Sam
Check the thread 'wrong centre' Might be some info there for you.
Alan
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Online RichardL

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Re: slipping clutch
« Reply #10 on: 18.08. 2015 00:39 »
The cork inserts were almost flush with the plates they were in. You can buy replacement corks and refit them. I suppose someone does that!

I think you can now find the inserts online, but I couldn't when I was rebuilding my clutch in 2005. I called up a local friction materials supply house and asked for samples of the right thickness. About the smallest sample they could provide was enough to do the job, maybe twice over. The material was asbestos-free, so I just cut out the chips on my band saw and ground the corners to radii that fit. Still working after about 4,800 miles and one replacement of solid plates.

Richard L.
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Offline duTch

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Re: slipping clutch
« Reply #11 on: 19.08. 2015 12:06 »

 I'm inclined to think that any oil that gets in against centrifugal force won't stay long before it's flung out by same centrifugals.....unless it's somehow sucked in through the bearing, and pumped out with same centrifugals  *conf*

 GB, my domed cover is really good at keeping the dust out of my spare basket on the shelf- amazingly convenient fit :! Too much involved in pulling it off everytime I feel like checking on things

  Geez O-B-1-Begeezas, no offence, but I hope no-one quotes that entire mammoth effort... *eek*
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Started building in about 1977/8 a on average '52 A10 -built from bits 'n pieces never resto intended -maybe 'personalised'
Have a '74 850T Moto Guzzi since '92-best thing I ever bought doesn't need a kickstart 'cos it bump starts sooooooooo(mostly) easy
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Offline Topdad

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Re: slipping clutch
« Reply #12 on: 19.08. 2015 14:03 »
My old plunger was a dry clutch and always stayed that way with the dome fitted . Re the dial gauge, as I like to be able to get neutral with ease it's very high on my want one list ,in the meantime you could use a piece of stiff wire to act as a pointer,I attach it to a nut on the barrel flange ,then position it  just over the clutch, pull in clutch, kick bike over and use to see how the pressure  plate behaves in relation to the pointer then adjust the springs to get it spinning round level. It really makes a difference as John says.
On mine I adjust the cable at the handlebar to loosen the cable right off to start the bike and once warm I tighten it up to enable neutral to be selected easy when coming to a halt .Once the bikes over the first start the clutch doesn't slip when riding but after everything cold it slips badly .  A job for the winter ! but til then nahhhhh. i'll ride . Cheers Bob
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Offline worntorn

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Re: slipping clutch
« Reply #13 on: 19.08. 2015 20:08 »
My 63 A10 clutch was slipping badly a few weeks ago when I first tried the bike. It turned out that the primary was over full and the oil was quite dark in colour. A change to ATF type F put an end to the slippage.

Glen
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Offline duTch

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Re: slipping clutch
« Reply #14 on: 20.08. 2015 01:58 »

When I adjust the clutch springs, I was using a hose clamp to hold the hand lever in (but I couldn't find it last time, so I utilized a special tool as per photo). .. Then I slip it in top gear and spin the rear wheel (as others also do) but just eyeball down the pressure plate. . is quicker than setting up the dial Guage. .. .  and works fine doesn't slip(since I put new plates in) or drag, and I easily get neutral at standstill *smile*
 [quote If the four spring clutch is "based on" Triumph clutch types, does anyone know if you can do the modifications to get an extra plate in?[/quote]
 Probably not Much help , but I don't know about the four springer, but I tried doing five friction plates in my Plunger; they fitted OK, but slipped a lot (as did four)because I couldn't get enough preload on the springs before they bound up, but with different Springs it might work. .
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Started building in about 1977/8 a on average '52 A10 -built from bits 'n pieces never resto intended -maybe 'personalised'
Have a '74 850T Moto Guzzi since '92-best thing I ever bought doesn't need a kickstart 'cos it bump starts sooooooooo(mostly) easy
Australia