Author Topic: 51 Plunger Fork Rebuild -  (Read 351 times)

Offline triplethreat3d

  • Moving Up
  • **
  • Join Date: Jun 2016
  • Posts: 8
  • Karma: 0
51 Plunger Fork Rebuild -
« on: 24.06. 2016 19:18 »
Just acquired a fork assembly with clamp-style sliders that fit with the original A7 7" brake for the bitsa project and now face the rebuild decision with no prior experience with these forks. Think I have following choices to make as the stanchions are not worthy to be used again.
1. standard replacement stanchions pt.# 89-5061 with bushes and standard springs, seals
2. chrome stanchions with bushes & standard springs
3. standard or chrome stanchions with progressive springs
4. standard or chrome stanchions with progressive springs & damper rods

Would really appreciate advice from riders of real A7/A10 bikes as I have no experience with these forks.  The sliders have domes in the bottom which appear to be a 4.5 cm high, stanchions are 58 cm.  I am about 165lbs and do not see ever having a rider as bike with have solo seat. Intent is to stick to paved highways and ride this for pleasure as long as I am able to kick the B40 to life (when motor is finished). 
Pics attached for reference.   All suggestions welcome before $$$$ spent.

Online muskrat

  • Global Moderator
  • Wise & Enlightened
  • **
  • Join Date: Jul 2009
  • Posts: 8511
  • Karma: 112
  • Lithgow NSW Oz
    • Shoalhaven Classic Motorcycle Club Inc
Re: 51 Plunger Fork Rebuild -
« Reply #1 on: 24.06. 2016 23:22 »
G'day tripletreat.
The sliders in the picture are from a latter model and won't accept the 51 7" brake. The top triple clamp with the steering lock is wrong for 51 as well. I'd say their off a 60 or there abouts with the full width hubs. It will all fit the 51 with the right hub for those sliders.
If money permitting I'd go the 4. Hard chrome stanchions with progressive springs & damper rods and stainless seal holders. That's what my 57 Cafe got. The 51 plunger just got the hard chrome stanchions and damper rods.
Cheers
'51 A7 plunger, '57 A7SS now A10CR,  '83 CB1100F, 88 FXST .
Australia
Muskys Plunger A7

Offline morris

  • Wise & Enlightened
  • *
  • Join Date: Aug 2012
  • Posts: 1657
  • Karma: 26
  • Antwerp, Belgium
Re: 51 Plunger Fork Rebuild -
« Reply #2 on: 25.06. 2016 10:42 »
Hi triplethreat,
I have the standard setup on the plunger, non chromed stanchions, standard solo springs. Working extremely well. Just spray the exposed stanchion parts with oil from time to time to prevent surface rust.
I think that if you wish to use the 7'' hub, depending if it's a hub with a strap, you could grind off the notch on the slider and fix the strap to the mudguard bracket?
'58 BSA A 10 SA
'52 BSA A 10 Plunger
'55 MORRIS ISIS
The world looks better from a motorbike
Belgium