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Swm 1982 Clutch Fix


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#1 reginald

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Posted 23 September 2010 - 01:40 AM

Hi Guys,
A very helpful past owner of my 1982 tl 320 let me know how he set the clutch up. As follows:
  • replaced clutch springs with 6 xr 650 valve springs A$35.00,
  • whacked on a venhill clutch cable and
  • uses a magura lever rather than standard

It works like a ty now, its great. I believe the plates were replaced with barnetts but still confirming that.


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#2 reginald

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Posted 23 September 2010 - 08:28 AM

Yep plates were barnett if anyone is chasing the part no. drop us a PM. And that should read AU $35 as in Australian dollars although there are roughly the same at the moment.

#3 scottie_b205

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Posted 22 September 2011 - 07:48 PM

I looked up the XR600/650 valve springs and there are two springs on each valve. Are the correct springs the bigger outer or smaller inner ones. That is what I see in the schematics. I am guessing the larger valves but don't want to pay to find out.

#4 b40rt

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Posted 22 September 2011 - 08:24 PM

Rotax clutch springs are available (in the UK anyway)I currently use 4 of the softest & 2 of the medium from the list below. I also have extended the clutch arm (inside clutch casing)and a dog leg clutch lever.
The end result is a 1 finger clutch, which willslip if you drop the clutch in 4th and above, fine 99% of the time.

Ross

(***N) - LOAD at 20.00mm compression

part no 239.620 clutch spring (169-N) 36.7mm
part no 239.625 clutch spring (212-N) 34.1mm
part no 239.741 clutch spring (255-N) 38mm

Edited by B40RT, 22 September 2011 - 08:25 PM.

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#5 scottie_b205

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Posted 23 September 2011 - 06:06 PM

I have a 240 which I installed a 280 complete top end on. There are only 4 springs in the clutch. They measure 36.6mm so I'm guessing they are the soft springs by your post. I don't know how old they are. I will order two medium springs and see how that goes. I don't remember what the clutch felt like at the lever.I bought and stripped the bike down almost two years ago. Too many projects and a bad experience with a shady powdercoater and i'm getting ready to assemble it.

#6 b40rt

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Posted 23 September 2011 - 06:17 PM

I have a 240 which I installed a 280 complete top end on. There are only 4 springs in the clutch. They measure 36.6mm so I'm guessing they are the soft springs by your post. I don't know how old they are. I will order two medium springs and see how that goes. I don't remember what the clutch felt like at the lever.I bought and stripped the bike down almost two years ago. Too many projects and a bad experience with a shady powdercoater and i'm getting ready to assemble it.


Length of an old spring is probably not that accurate an indication, measure the thickness of a coil and I will see if I can compare it to some of the known springs I have. (I bought a selection)
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#7 scottie_b205

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Posted 24 September 2011 - 12:39 AM

Spring measurements as follows:

2.46mm thick

7 coils

18mm wide

36.5mm long

#8 b40rt

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Posted 24 September 2011 - 04:15 PM

Spring measurements as follows:

2.46mm thick

7 coils

18mm wide

36.5mm long

2.10 = part no 239.620 16.6 wide

2.34 = part no 239.625 16.80 wide

2.46 = part no 239.741 18mm wide

All 7 coils.

Think 239.741 must be standard, I'm currently running 3 x 620 + 3 x 625.

Edited by B40RT, 24 September 2011 - 04:23 PM.

Never argue with stupid people, they will drag you down to their level and then beat you with experience. Mark Twain

#9 scottie_b205

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Posted 25 September 2011 - 01:31 AM

Thank you for the spring info. :thumbup: I will try your setup. If it slips for me, I can always try two of my stiffer springs.

#10 reginald

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Posted 13 June 2012 - 12:34 PM

Had the clutch actuating arm lengthened by 3mm, and fitted domino off no. 2 bike and its nice and light but now I can't disengage the clutch fully without using my whole hand i.e. holding the lever in so it hits my other two fingers does not disengage it fully. No biggy but swings and round abouts eh? Will slip in 6th gear if you wind on too quick from low revs but Ive incorrectly been using a low cost car engine oil and changing it frequently assuming it wont have friction modifiers in it as it is cheap. Will try a castrol gearbox oil and if it still slips might try some of the springs suggested above.


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#11 feetupfun

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Posted 14 June 2012 - 07:40 AM

If you have contaminated the friction plates with friction modifier additive, it will not clean up by just changing the oil back to non-friction-modified. Having said that, I thought that including friction modifiers in car engine oils went out of favour years ago
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#12 woody

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Posted 14 June 2012 - 04:25 PM

Had the clutch actuating arm lengthened by 3mm, and fitted domino off no. 2 bike and its nice and light but now I can't disengage the clutch fully without using my whole hand i.e. holding the lever in so it hits my other two fingers does not disengage it fully.


That's the problem I found when trying to set up my Jumbo clutch. The actuator travel is generally not enough to allow the plates to clear properly, therefore they can drag. If you adjust it to clear the drag you can get slip in the higher gears or even 3rd and 4th if you're howling it in sections. The clutch is also slow to take up when it is like that. They're a real pain to set up and vary from bike to bike.

Lengthening the arm makes it lighter in action but worsens the affect on the actuator as you need more travel on the lever to clear the plates. I think there are 3 different actuator designs with different size ball bearings (at least there are for the Jumbo which uses a different clutch case)

Best fix on the 'ordinary' models is to fit the clutch case from the Aprilia with the external arm which gives a much better action and solves the problem. Unfortunately, that wasn't an option on the Jumbo due to the different case design.

The actuator design inside the clutch casing is awful.

#13 reginald

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Posted 28 July 2012 - 07:49 AM

Hi All, I have a recently rebuilt engine in my TL 320 and the clutch is incredibly light [good for comp.] but slips in the higher gears badly [no good for trial riding between sections]. Was wondering whether you could put the clutch back together in a way that makes this happen?? It didn't do this before. While this may seem obvious I also installed a clutch cover from my no. 2 bike after the rebuild with a lengthened actuator arm so thought that's where the light action came from. But im guessing that will having nothing to do with the slippage?
Any thoughts welcomed.

#14 motoswm

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Posted 28 July 2012 - 08:18 PM

Did you adjust the screw on the clutch arm when you swapped the cases ? If not unscrew it a quarter turn at a time (take up the slack on the cable) and see if that cures it.

If not it sounds like clutch springs. I rebuilt an Aprilia TX300 recently that had exactly the same problem. This one was running on 4 clutch springs and was super light in the first 3 gears and slipped like hell in top. I stuck another 2 springs in and it cured it.

#15 reginald

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Posted 28 July 2012 - 09:56 PM

Thanks will do. I did try replacing to of the light springs with two standards and no change even tho a bit stiffer at lever. More and more it sounds like the replacement of the clutch cover means that actuator is adjusted differently or has different width parts isn't allowing full release of basket.
Thanks for tip SWM moto.




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