« previous next »
Pages: [1]   Go Down

Author Topic: tap sizes  (Read 938 times)

Offline Drew Back

  • A's Good Friend
  • ***
  • Join Date: Jun 2014
  • Posts: 172
  • Karma: 0
tap sizes
« on: 16.03. 2015 03:22 »
Can someone tell me the correct thread size for the head bolts and rocker box bolts..It seems there are so many different thread sizes and I dont know what tap sizes to purchase..Are they the same sizes as the A10 Iron head??
Logged

Offline duTch

  • Ricketty Rocketty Golden Flashback
  • Wise & Enlightened
  • *
  • Join Date: Oct 2011
  • Posts: 4528
  • Karma: 41
Re: tap sizes
« Reply #1 on: 16.03. 2015 06:32 »

 (Fairly sure) Head bolts are 3/8" BSF (one of the few uses of bsf on a pre-unit BSA)
 Alloy head rocket cover long bolts on mine are 5/16" BSC, all other screw ins are WW so far as I know
Logged
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 wardleybob

  • A's Good Friend
  • ***
  • Join Date: Oct 2012
  • Posts: 109
  • Karma: 3
Re: tap sizes
« Reply #2 on: 16.03. 2015 18:44 »
As dutch says 3/8 bsf  5/16  bsf.
Logged

Online muskrat

  • Global Moderator
  • Wise & Enlightened
  • **
  • Join Date: Jul 2009
  • Posts: 11047
  • Karma: 132
  • Lithgow NSW Oz
    • Shoalhaven Classic Motorcycle Club Inc
Re: tap sizes
« Reply #3 on: 16.03. 2015 18:55 »
The r/box bolts are same for iron and alloy heads, 4 of 5/16" x 3-1/2" CEI (BSC or Cycle thread) and 1 of 1-1/2". The studs differ, iron head 4 of 5/16"-18-26 x 1-5/16" BSW/CEI, alloy head 4 of 5/16"-18-26 x 1-13/16" BSW/CEI. The front studs on the plunger are 1-7/16" long.
3/8" BSF is correct for head bolts.
Cheers
Bob got in front.
Logged
'51 A7 plunger, '57 A7SS racer now a A10CR, '78 XT500, '83 CB1100F, 88 HD FXST, 2000 CBR929RR ex Honda Australia Superbike .
Australia
Muskys Plunger A7

Offline Drew Back

  • A's Good Friend
  • ***
  • Join Date: Jun 2014
  • Posts: 172
  • Karma: 0
Re: tap sizes
« Reply #4 on: 17.03. 2015 14:28 »
Thank you all again for the help..
Logged
Pages: [1]   Go Up
« previous next »