Author Topic: Clutch Spring Adjustment  (Read 12640 times)

Offline redbeeza

  • A's Good Friend
  • ***
  • Join Date: Aug 2010
  • Posts: 41
  • Karma: 1
Re: Clutch Spring Adjustment
« Reply #60 on: 19.07. 2011 19:20 »
I think I've sorted it out.

It just seems to have been an adjustment thing, but I think a plate or two must have been sticking or jamming somehow when I first started to set up the clutch and that complicated matters.

To recap:  I'd got the clutch to work (with the primary cover off) but the nuts on the clutch springs were unscrewed an awful long way.  I'd also had trouble with the kickstart sticking, accompanied by a graunching sound, after I'd put the primary cover back and tightened it down.

When I had another think about the clutch and drew a few diagrams to help me understand the relationship between the various different adjusters I decided to approach the problem from the other direction.

The clutch was working and lifting square but the screws were too slack and I couldn't understand why the clutch was still not slipping.  Instead of fiddling with the spring tension again, I screwed in the adjuster at the gearbox end half a turn: the clutch then slipped.  I then started to screw the springs in 1/4 turn at a time and regularly checked the pressure plate was lifting square, readjusting when necessary.  I got the clutch spring nuts screwed back down to almost where the threads were beginning to show and the clutch was still slipping, so I went back to the adjuster at the gearbox end and slackened it of gradually until the clutch stopped slipping.  A little bit more tweaking on the spring nuts and a bit of slack put in the cable by adjusting the handlebar lever and we were there:  spring nuts down to where they should have been; light lever operation; clutch spins freely on the kickstart when the lever's pulled in.  Still haven't road tested it yet but I think I'm there.

Coming to the graunching sound.  From one of my photos, Groily noticed there was a spacer missing from where the inner primary cover bolts to the frame at the rear.  This spacer pushes the inner cover out at this point.  I thought that by adding a spacer here, my problem with the tightening kickstart action and the graunching would be worse because I had convinced myself that something was catching on the inside of the outer primary cover.  I thought this because I had discovered a light scoring on the inside of the cover where the clutch rotates.

I thought I'd give the spacer a go though because there should be one anyway.  I had noticed that the outer primary cover didn't sit very flat on the inner before tightening and could be rocked maybe 1/4", so I tried adding different thicknesses of washers to where the spacer should sit to try to reduce this.  I got the gap down to about 1/8" and left these washers in in place of the spacer on reassembly.

On tightening down the outer primary cover screws and checking kickstart action: nice and free and no graunching sound.  I can only think that the primary inner case was catching on the back of the clutch drum somehow and causing the trouble... all would be hidden from view, and that the scoring I had seen on the inside of the outer cover was a historical red herring.

Can anyone tell me the thickness that said spacer should be on a '62 model A10?  My inner cover is now spaced out about 5mm in new money.

Thanks for all the help.  It led me to sit down and understand exactly how the whole mechanism of the clutch works together, and saved me from sawing a bit off the pushrod...

1962 A10 Super Rocket.  First Brit bike, first rebuild.

Online muskrat

  • Global Moderator
  • Wise & Enlightened
  • **
  • Join Date: Jul 2009
  • Posts: 8915
  • Karma: 113
  • Lithgow NSW Oz
    • Shoalhaven Classic Motorcycle Club Inc
Re: Clutch Spring Adjustment
« Reply #61 on: 19.07. 2011 20:46 »
Glad you've finally got it sorted Terry. I know sometimes I (we) dive in looking for major problems when it can be something as simple as plates stuck together. At least now you have a good understanding of how the clutch works.
As for the spacer. If the inner cover is still flat (not warped) it's just a matter of doing up the 5 screws (use spacers on the front 3) and use washers or a made up spacer to fill the gap. It could be 1mm or 10mm, it varies.
Check that the outer cover is flat on a piece of glass or other flat surface. If it is bolt it up to the inner before working out the spacers required.
'51 A7 plunger, '57 A7SS now A10CR,  '83 CB1100F, 88 FXST .
Muskys Plunger A7

Online groily

  • Wise & Enlightened
  • *
  • Join Date: Jul 2007
  • Posts: 1319
  • Karma: 24
Re: Clutch Spring Adjustment
« Reply #62 on: 19.07. 2011 22:31 »
Brilliant Terry, this is Good News. Wasn't sure if a spacer was missing or not, but from bitter experience I know that stressing the cases to close them up is BAD and that there has to be something (usually) to get the alignment correct.  Quarter inch says 'yes', something needed doing - and when I had the same hassle light years ago it seems now, the noise was at the back not the front of the clutch. Excellent if a washer or two will serve, but as Musky says, no golden rule as far as I know on How Thick. The main thing is it's all looking good and you'll be out there again frightening the natives. I hope!

Offline shabashow

  • A's Good Friend
  • ***
  • Join Date: May 2008
  • Posts: 139
  • Karma: 0
Re: Clutch Spring Adjustment
« Reply #63 on: 10.08. 2011 15:02 »
Glad you managed to get a resolution to your problem.
The combined IQ of our BSA experts on the forum must be astronomical, and whatever the problem, someone will come up with a solution, or at least helpful comment.

slithly off topic - back to the kick start cotter pin -

I had it in the 'reverse' direction for a short period a while back (worried about it dropping off due to the nut loosening off) and thought it didn't make any real difference until I went to open the tool box on my 52 plunger. With the pin in the wrong direction, the kickstart lever sits slightly more angled to the rear, which fouls the toolbox lid when it is opened. I turned the cotter pin back around the 'right' way, with the nut on the top and releived my fears of the nut loosening off by liberal application of locktight and using two nuts to lock them together.

Offline Butch (cb)

  • Wise & Enlightened
  • *
  • Join Date: Aug 2010
  • Posts: 1664
  • Karma: 16
Re: Clutch Spring Adjustment
« Reply #64 on: 31.08. 2011 15:53 »
Yeah - I've always inserted cotter pins so that you push in to the taper. Still running them front and back on my tandem.
Warning - observations made by this member have a 93% unreliability rating.

Of Bikes; various, including ...
'58 S/Arm Iron Head Flash Bitza

Online Joolstacho

  • Resident Legend
  • *****
  • Join Date: Jan 2010
  • Posts: 646
  • Karma: 5
Re: Clutch Spring Adjustment
« Reply #65 on: 18.04. 2013 09:28 »
Just in case others may have a similar problem. While setting mine up (4-spring) I found that one spring was fouling it's cup, -at high lift, a coil on the spring was spreading slightly, just enough to drag and 'catch' in it's cup.