Author Topic: Why I recently needed a s/a inner gearbox cover  (Read 521 times)

Online terryg

  • Valued Contributor
  • ****
  • Join Date: Nov 2012
  • Posts: 463
  • Karma: 6
    • thecarshipenterprise

The photo below shows the cause of my recent plea for help to find a replacement inner s/a gearbox cover.  Thanks again to Edboy for coming up trumps - within an hour!  Without his help we, the boys and I, would have missed our cross channel ferry for sure.

I've not seen this type of failure before but wonder if anyone else has.

Please forgive any inaccuracy in the following but I'm just having to learn the fine details of the kickstart mechanism.

The gearbox in question is fitted with a '1-o-clock' quadrant, which results in the end stop being reached well before the bottom of the kicking stroke.  When my son Matt (a big lad, not used to riding these old bikes) enthusiastically swung on the kickstarter we were both surprised to see a puddle of gearbox oil quickly form under the bike.  On closer examination the reason became clear, as you can see.

I'm just now getting back to finding out whether the same can be avoided in future without changing to an '11-o-clock' quadrant, less convenient for the rearset footrests.
Terry
'57 'SR', '59 SR, '63 RGS

Online bsa-bill

  • Wise & Enlightened
  • *
  • Join Date: Mar 2006
  • Posts: 5455
  • Karma: 62
Re: Why I recently needed a s/a inner gearbox cover
« Reply #1 on: 09.10. 2015 21:50 »
Have not seen that but can understand it, on my inner cover the stop peg for the kickstart was slack and had elongated the hole it was in, I'd think this could be a factor in a crack starting, packed mine out with metal paste stuff ??, seems to be holding
All the best - Bill
1961 Flash - stock, reliable, steady, fantastic for shopping
1959 Rocket Gold Flash - blinged and tarted up  would have seizure if taken to  Tesco

Offline duTch

  • Ricketty Rocketty Golden Flashback
  • Wise & Enlightened
  • *
  • Join Date: Oct 2011
  • Posts: 4540
  • Karma: 41
Re: Why I recently needed a s/a inner gearbox cover
« Reply #2 on: 09.10. 2015 23:18 »
 It took me a while to see the bits clearly *eek*....bit of a problem...

 But the 'Stop Peg' is a return stop...I wouldn't have thought it'd go so far as to engage the other side of the 'segment gear' *smile*.....?
 I guess it does, so I guess that's one of the differences that I had in mind in another thread the other day...

   Maybe you can machine *work* a longer cutout where the stop engages the 'quadrant'..??

 ps- 
Quote
I'd think this could be a factor in a crack starting,

        I thought this was a pun on a starting technique  *shh*

 *ex* *ex*  While looking at Pedros issue I realised my idea won't fix anything (because likely it already has that, and I was mixed up with the offending spring side- which could still be cut deeper?), but is your 'quadrant' one of the splined type; if so maybe you can rotate one spline- which will go a long way round *dunno2*


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

Offline duTch

  • Ricketty Rocketty Golden Flashback
  • Wise & Enlightened
  • *
  • Join Date: Oct 2011
  • Posts: 4540
  • Karma: 41
Re: Why I recently needed a s/a inner gearbox cover
« Reply #3 on: 10.10. 2015 00:19 »

 
Quote
   Maybe you can machine  a longer cutout where the stop engages the 'quadrant'..??
Trouble is it would potentially be at the expense of spring tension *conf*
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

Online terryg

  • Valued Contributor
  • ****
  • Join Date: Nov 2012
  • Posts: 463
  • Karma: 6
    • thecarshipenterprise
Re: Why I recently needed a s/a inner gearbox cover
« Reply #4 on: 10.10. 2015 06:22 »
I appreciate your thoughts Dutch. There are one or two posts on kickstart quadrants, on this and also the Britbike forum.
I think Muskrat has described modifying a quadrant cutout to allow more rotation. There is also information around on an offset stop dowel, which I think might be a Pearson idea.
I've not got the bike in pieces just at the moment, nor did I notice when hastily replacing the inner cover whether the quadrant is the pressed up or one piece type.
I've read that the 60 degree rotation offered by the pressed up assembly is too much, which takes us back to modified cutouts and offset stop pegs.
No doubt things will become clearer when it is in pieces once again.

Out of interest, my RGS has both a 1-o-clock quadrant and a cranked kickstarter. Since having this problem on the replica RGS I realised that the kickstart throw stops well before the 6-o-clock position on it too. Another concern to deal with some time.

Right now bump starting is feeling like the safe option! (joke)
Terry
'57 'SR', '59 SR, '63 RGS

Offline muskrat

  • Global Moderator
  • Wise & Enlightened
  • **
  • Join Date: Jul 2009
  • Posts: 8261
  • Karma: 106
  • Lake Conjola NSW Oz
    • Shoalhaven Classic Motorcycle Club Inc
Re: Why I recently needed a s/a inner gearbox cover
« Reply #5 on: 10.10. 2015 20:53 »
G'day Terry.
I can't find that post so here's the pics again. the stop peg is reduced in diameter and the quadrant is recessed to move the lever forward. The gears still take up in the normal possition and throw.
Cheers
'51 A7 plunger, '57 A7SS now A10CR,  '83 CB1100F, 88 FXST .
Australia
Muskys Plunger A7

Online terryg

  • Valued Contributor
  • ****
  • Join Date: Nov 2012
  • Posts: 463
  • Karma: 6
    • thecarshipenterprise
Re: Why I recently needed a s/a inner gearbox cover
« Reply #6 on: 10.10. 2015 21:16 »
Hello Musky. Yes, those are the pics I recall from your post that I found.

There's another bit to this story and I'm reminded of it looking at your modified quadrant.

When I took the outer cover off the gearbox, after it had dumped the oil, I realised that the initial part of the throw (about 50-60 degrees) was not turning the motor. The reason was that a piece with the first 4-5 teeth had broken off the leading part of the quadrant.

I can't say exactly when this happened, partly because there were two of us getting the bike ready for a run.

All I can say now is that it's one more thing to put right.

Old machines - don't you just love them?
Terry
'57 'SR', '59 SR, '63 RGS

Offline duTch

  • Ricketty Rocketty Golden Flashback
  • Wise & Enlightened
  • *
  • Join Date: Oct 2011
  • Posts: 4540
  • Karma: 41
Re: Why I recently needed a s/a inner gearbox cover
« Reply #7 on: 11.10. 2015 01:28 »

 I wrote this up last night, so not sure if it'll be relevant/make sense *conf*

 Well yesterday I got under-excited and over curious, so had a dig in the various spare boxes I've accumulated, and the 'splined kick quadrant' I have is in the cover that came on the box I'm currently using- it's an early box with the flat kicker return spring, and the box came with a scroll on the output sprocket and complementary oil slinger thingy (in place of seal), so I believe it's a ridgy-didge early one...

  The point of this is, I'm asking others who know, just when were these quadrants used- I thought they may have been a later innovation, but sometimes good ideas get phased out..? ... *conf*...
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

Offline duTch

  • Ricketty Rocketty Golden Flashback
  • Wise & Enlightened
  • *
  • Join Date: Oct 2011
  • Posts: 4540
  • Karma: 41
Re: Why I recently needed a s/a inner gearbox cover
« Reply #8 on: 12.10. 2015 00:47 »

 I was just fiddling and, checked my kick lever, is a later  8" folding type (irrelevant?) and it sits at ~45˚ engages after~10˚, and remains engaged until the stop just past bottom centre....and here's a reference pic of the splined 'quadrant' I have- probably same as Muskys, and has a machined slot for flat return spring(arrowed)....it's not currently in use

 NB reference: By my calculating, if the Quadrant was a full circle, it would have 34 Teeth and ratchet pinion 17T, mechanical advantage= 2:1
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