Author Topic: CB350f bore size  (Read 764 times)

Offline royhall

  • SOHC Jedi
  • Posts: 3380
  • Keep biking I'm not quite bankrupt yet
    • View Profile
CB350f bore size
« on: August 18, 2017, 07:42:10 AM »
Can anyone confirm the piston to bore clearance for a CB350F. I have found so many differing sizes, but it appears to be 0.0008" (eight tenths of a thou) but I have seen as little as 0.0005" specified by Hondaman but that does seem very tight and risking seizure. What clearance have you guys used with good results. Cheers.
Current bikes:
TriBsa CCM 350 Twin
Honda CB350F in Candy Bacchus Olive
Honda CB750F2 in Candy Apple Red
Triumph Trident 660 in Black/White
Triumph T100C
Suzuki GS1000HC
Honda CB450K0 Black Bomber
Honda CB750K5 in Planet Blue Metallic (Current Project)

Offline kevski

  • SOHC Pro
  • Posts: 508
    • View Profile
Re: CB350f bore size
« Reply #1 on: August 18, 2017, 08:35:38 AM »
I have two figures and it equates to 9.8 thou or 250 microns which is what I work to.

Offline Tomb

  • SOHC Pro
  • Posts: 658
    • View Profile
Re: CB350f bore size
« Reply #2 on: August 18, 2017, 10:14:05 AM »
I have two figures and it equates to 9.8 thou or 250 microns which is what I work to.

Wow that's HUGE, are you sure that's not the wear limit? even if it were its still big.
Tom
'73 CB550 with CB500 engine café racer
'62 CB77 Sprinter
'70 CD175
'78 CB550 with sidecar
'80 Z50R
And a load of old Yamaha 1100's

Offline Nurse Julie

  • 1977 CB550/4 Mongrel Brat. 1974 UK 500/4 K1. Honda CD250u.
  • Grogu
  • *
  • Posts: 8206
    • View Profile
Re: CB350f bore size
« Reply #3 on: August 18, 2017, 10:52:00 AM »
Gosh, with that clearance I thought you were talking about Brit bikes all of a sudden, even then it would be too much.......Dick and bucket come to mind ;D ;D ;D
LINK TO MY EBAY PAGE. As many of you know already, I give 10% discount and do post at cost to forum members if you PM me direct.
https://www.ebay.co.uk/sch/julies9731/m.html?item=165142672569&rt=nc&_trksid=p2047675.m3561.l2562

LINK TO MY CB400/4 ENGINE STRIP / ASSESSMENT AND REBUILD...NOW COMPLETE
http://www.sohc.co.uk/index.php/topic,14049.msg112691/topicseen.html#new

Offline royhall

  • SOHC Jedi
  • Posts: 3380
  • Keep biking I'm not quite bankrupt yet
    • View Profile
Re: CB350f bore size
« Reply #4 on: August 18, 2017, 03:22:45 PM »
I have two figures and it equates to 9.8 thou or 250 microns which is what I work to.
Shouldn't that be 25 microns?
Current bikes:
TriBsa CCM 350 Twin
Honda CB350F in Candy Bacchus Olive
Honda CB750F2 in Candy Apple Red
Triumph Trident 660 in Black/White
Triumph T100C
Suzuki GS1000HC
Honda CB450K0 Black Bomber
Honda CB750K5 in Planet Blue Metallic (Current Project)

Offline Tomb

  • SOHC Pro
  • Posts: 658
    • View Profile
Re: CB350f bore size
« Reply #5 on: August 18, 2017, 03:41:38 PM »
10 thou is 1/4 of a mm so 9.8 thou is about 250 microns
Tom
'73 CB550 with CB500 engine café racer
'62 CB77 Sprinter
'70 CD175
'78 CB550 with sidecar
'80 Z50R
And a load of old Yamaha 1100's

Offline royhall

  • SOHC Jedi
  • Posts: 3380
  • Keep biking I'm not quite bankrupt yet
    • View Profile
Re: CB350f bore size
« Reply #6 on: August 18, 2017, 04:23:16 PM »
10 thou is 1/4 of a mm so 9.8 thou is about 250 microns
Exactly, it should read 25 microns or 0.00098" not 250 microns thats way too much?
Current bikes:
TriBsa CCM 350 Twin
Honda CB350F in Candy Bacchus Olive
Honda CB750F2 in Candy Apple Red
Triumph Trident 660 in Black/White
Triumph T100C
Suzuki GS1000HC
Honda CB450K0 Black Bomber
Honda CB750K5 in Planet Blue Metallic (Current Project)

Offline kevski

  • SOHC Pro
  • Posts: 508
    • View Profile
Re: CB350f bore size
« Reply #7 on: August 18, 2017, 04:53:41 PM »
I cocked up my sums there and am now looking for more info on it now.

Offline Trigger

  • Grogu
  • *
  • Posts: 8434
  • Engines built on reputation, not advertising.
    • View Profile
Re: CB350f bore size
« Reply #8 on: August 18, 2017, 09:39:37 PM »
All depends on the piston manufacture ( Different grades of alloy ) 0.0005"to 0.0008" is ok for OEM Honda.

Offline royhall

  • SOHC Jedi
  • Posts: 3380
  • Keep biking I'm not quite bankrupt yet
    • View Profile
Re: CB350f bore size
« Reply #9 on: August 19, 2017, 08:13:46 AM »
All depends on the piston manufacture ( Different grades of alloy ) 0.0005"to 0.0008" is ok for OEM Honda.
Good point about the piston make. In this case I'm talking about the Cruzinimage pistons and rings.
Current bikes:
TriBsa CCM 350 Twin
Honda CB350F in Candy Bacchus Olive
Honda CB750F2 in Candy Apple Red
Triumph Trident 660 in Black/White
Triumph T100C
Suzuki GS1000HC
Honda CB450K0 Black Bomber
Honda CB750K5 in Planet Blue Metallic (Current Project)

Offline royhall

  • SOHC Jedi
  • Posts: 3380
  • Keep biking I'm not quite bankrupt yet
    • View Profile
Re: CB350f bore size
« Reply #10 on: August 19, 2017, 08:39:52 AM »
All depends on the piston manufacture ( Different grades of alloy ) 0.0005"to 0.0008" is ok for OEM Honda.
Good point about the piston make. In this case I'm talking about the Cruzinimage pistons and rings.
Just for info of anybody watching this thread, the correct clearance for a 350F with Cruzinimage pistons is 0.0009" to 1 thou. Cheers.
Current bikes:
TriBsa CCM 350 Twin
Honda CB350F in Candy Bacchus Olive
Honda CB750F2 in Candy Apple Red
Triumph Trident 660 in Black/White
Triumph T100C
Suzuki GS1000HC
Honda CB450K0 Black Bomber
Honda CB750K5 in Planet Blue Metallic (Current Project)

 

SimplePortal 2.3.5 © 2008-2012, SimplePortal