Author Topic: Drive chain catching on the back of the chain case  (Read 1223 times)

Offline JSF

  • Moving Up
  • **
  • Join Date: May 2011
  • Posts: 29
  • Karma: 0
Hello all

A query I'm hoping someone can shed a little light on which I've noticed having done more miles- essentially the drive chain is rubbing on the back of the chain case and making it's own groove in the alloy! I can't quite fathom it from the manual but it's like there's a spacer missing or that something is misaligned.

Has anyone ever heard of this? The gearbox has been out recently so could We have made a sows ear in refitting it? (Everything looks and works ok to my untrained eye)

Any suggestions gratefully received and thanks again in advance

John

58 Golden Flash

Offline a10gf

  • Wise & Enlightened
  • *
  • Join Date: Sep 2006
  • Posts: 2805
  • Karma: 42
  • West Coast, Norway & Alpes Maritimes, France
    • A10 GF
Re: Drive chain catching on the back of the chain case
« Reply #1 on: 21.09. 2013 19:29 »
Hello, I made some 'nice' grooves once upon a time, fitted the wrong type of chain (was some kind of heavy duty chain), so first of all double check what kind of chain is fitted.

A10 GF '53 My A10 website
"Success only gets you a ticket to a much more difficult task"

Online muskrat

  • Global Moderator
  • Wise & Enlightened
  • **
  • Join Date: Jul 2009
  • Posts: 8324
  • Karma: 107
  • Lithgow NSW Oz
    • Shoalhaven Classic Motorcycle Club Inc
Re: Drive chain catching on the back of the chain case
« Reply #2 on: 21.09. 2013 21:22 »
 I agree with a10gf, many moons ago I fitted an O ring chain that fowled the inner primary. It didn't leave the shed.
Cheers
'51 A7 plunger, '57 A7SS now A10CR,  '83 CB1100F, 88 FXST .
Australia
Muskys Plunger A7

Offline JSF

  • Moving Up
  • **
  • Join Date: May 2011
  • Posts: 29
  • Karma: 0
Re: Drive chain catching on the back of the chain case
« Reply #3 on: 22.09. 2013 08:46 »
Thanks both - will check this out but the chain looks to have been on the bike for years so fear it's since we've had it apart!
58 Golden Flash

Online bsa-bill

  • Wise & Enlightened
  • *
  • Join Date: Mar 2006
  • Posts: 5474
  • Karma: 64
Re: Drive chain catching on the back of the chain case
« Reply #4 on: 22.09. 2013 08:59 »
Hi John - if we are talking about the primary chaincase (you did mention alloy) and swinging arm models? is the wear on the rear or the back of the chaincase (does that make sense) if the rear then probably you need a link or half out of the primary chain, if it's the back ( nearest the engine and gearbox) have you replaced the little spacer or washer/s between the lug on the chaincase and the frame (the chaincase lug goes inside the frame)

all the best - Bill
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: Drive chain catching on the back of the chain case
« Reply #5 on: 22.09. 2013 12:25 »

  By your wording, it sounds like you've investigated, but-.......... (and you do mean FINAL drive, not Primary??)
If you haven't already done so, maybe employ a mirror to look along the chain, and up under(one of those oversize dentist ones from auto shop are handy), get it on the centre stand, remove the chainguard if necessary, and turn the wheel. you should hear/see something scraping.....??
 Wouldn't a spacer(other than necessary for the natural gap) between chaincase and frame make it worse??
 Isn't there a spacer between the inner case and crank-case?    Maybe that's missing?? or maybe needs (thicker) one??

 also check that the sprocket nut is done up tight, a loose one of those would allow the sprocket/chain to float over onto the primary...??
 
 I had a similar but different thing, but it was the con-link had caught the corner of the chainguard
 good Luck, cheers duTch
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 chaterlea25

  • Wise & Enlightened
  • *
  • Join Date: Jun 2009
  • Posts: 3283
  • Karma: 47
Re: Drive chain catching on the back of the chain case
« Reply #6 on: 22.09. 2013 18:17 »

Hi JSF
If its the primary chain rubbing??? then its likely that you left out spacer/washers between the frame and inner primary case bottom mount near the footrest ???

HTH
John
1961 Super Rocket
1963 RGS (ongoing)

Offline JSF

  • Moving Up
  • **
  • Join Date: May 2011
  • Posts: 29
  • Karma: 0
Re: Drive chain catching on the back of the chain case
« Reply #7 on: 23.09. 2013 13:06 »
Thanks for the replies and additional input - I'll take another look and update. 

For clarity, it's a swinging arm bike and it's the drive chain that's catching - as you look from the rear of the bike along the chain, the chain is too close to the LHS (at the engine end) and is cutting a groove in the back of the engine casing! Almost like to front sprocket is protruding too far (but the chain run looks fine) so the outside of the drive chain is getting covered in shiny alloy!

I'll try a few of the ideas and as above report back on progress!

Thanks again

John
58 Golden Flash

Offline a10gf

  • Wise & Enlightened
  • *
  • Join Date: Sep 2006
  • Posts: 2805
  • Karma: 42
  • West Coast, Norway & Alpes Maritimes, France
    • A10 GF
Re: Drive chain catching on the back of the chain case
« Reply #8 on: 23.09. 2013 13:16 »
Quote
and is cutting a groove in the back of the engine casing

You may have some sprocket alignment problem, but here's the result of my 'reinforced' large chain experiment! But only cosmetic harm done.

A10 GF '53 My A10 website
"Success only gets you a ticket to a much more difficult task"

Offline duTch

  • Ricketty Rocketty Golden Flashback
  • Wise & Enlightened
  • *
  • Join Date: Oct 2011
  • Posts: 4540
  • Karma: 41
Re: Drive chain catching on the back of the chain case
« Reply #9 on: 24.09. 2013 10:41 »
Quote
For clarity, it's a swinging arm bike and it's the drive chain that's catching - as you look from the rear of the bike along the chain, the chain is too close to the LHS (at the engine end) and is cutting a groove in the back of the engine casing! Almost like to front sprocket is protruding too far (

Yup JFK, to reiterate, maybe not, but check the G'Box sprocket nut, and I think you mean Chain case
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 Topdad

  • bob hebdon
  • Wise & Enlightened
  • *
  • Join Date: May 2011
  • Posts: 2247
  • Karma: 32
  • l
Re: Drive chain catching on the back of the chain case
« Reply #10 on: 24.09. 2013 13:23 »
As per Dutch's thought i'd check the final drive g/box cog for tightness,or it may develope  into a bigger problem. never tried but you may be able to insert a large flat screwdriver or bar to see if you could prise the chain and cog inwards ,don't go mad and damage something else but if you can see it move you'll know how to sort it, best of luck, BobH
" rules are made for the guidance of wise men and the blind obediance of fools"
United Kingdom