« previous next »
Pages: 1 [2]  All   Go Down

Author Topic: 67.5 mm =cc??  (Read 5100 times)

0 Members and 1 Guest are viewing this topic.

Offline lash

  • Expert
  • ****
  • Posts: 761
Re: 67.5 mm =cc??
« Reply #25 on: November 27, 2019, 10:06:47 PM »
It will be a while before I can measure the case... :-\
Logged
Analog mind in a digital world..

Offline BPellerine

  • Master
  • *****
  • Posts: 2,222
Re: 67.5 mm =cc??
« Reply #26 on: November 28, 2019, 08:29:18 AM »
Quote from: Terry in Australia on November 27, 2019, 06:54:06 PM
Quote from: lash on November 27, 2019, 05:56:43 PM
Not sure what you mean about bigger base gasket and grind away?

The "Blue Ridge Mountain engineer" method of boring each cylinder hole in your top case is to put the oversize base gasket in place, mark the cases tracing the bigger holes, remove the gasket and get stuck into it with a die grinder or dremel tool, File, Bowie Knife,  or whatever cutting instrument you have available, usually conducted while drinking moonshine and wearing Dickies overalls and a straw hat. ;D
haha,just one way of doing it if you dont have access to a good machine shop,could be tapered sleeves,cyclex?made pistons to clean up a 67mm bore,with 67.5,I think they also made tapered sleeves,as did henry abe which I have.bill
Logged
1978 CB 750K ard and webers
another anfob

Offline 754

  • Really Old Timer ...
  • *******
  • Posts: 29,058
Re: 67.5 mm =cc??
« Reply #27 on: November 28, 2019, 10:13:38 AM »
You mean stepped sleeves.
 I got to ask the OP, when you measure the pistons, has to be at the skirts, 90 degrees to write pin... not sure where you measured.
Logged
Maker of the WELDLESS 750 Frame Kit
dodogas99@gmail.com
Kelowna B.C.       Canada

My next bike will be a ..ANFOB.....

It's All part of the ADVENTURE...

73 836cc.. Green, had it for 3 decades!!
Lost quite a few CB 750's along the way

Offline PeWe

  • Really Old Timer ...
  • *******
  • Posts: 15,575
  • Bike almost back to the 70's 2015
Re: 67.5 mm =cc??
« Reply #28 on: November 28, 2019, 12:07:24 PM »
CyckeX still sell that kit with 67.5mm Wiseco pistons and sleeves. CR 10.25:1They call it "915cc" which is not correct, diam is.

They sell 890cc too. CR 12.5:1
« Last Edit: November 28, 2019, 08:43:54 PM by PeWe »
Logged
CB750 K6-76  970cc (Earlier 1005cc JMR Billet block on the shelf waiting for a comeback)
CB750 K2-75 Parts assembled to a stock K2

Updates of the CB750 K6 -1976
http://forums.sohc4.net/index.php/topic,180468.msg2092136.html#msg2092136
The billet block build thread
http://forums.sohc4.net/index.php/topic,49438.msg1863571.html#msg1863571
CB750 K2 -1975  build thread
http://forums.sohc4.net/index.php/topic,168243.msg1948381.html#msg1948381
K2 engine build thread. For a complete CB750 -75
http://forums.sohc4.net/index.php/topic,180088.msg2088008.html#msg2088008
Carb jetting, a long story Mikuni TMR32
http://forums.sohc4.net/index.php/topic,179479.msg2104967.html#msg2104967

Offline lash

  • Expert
  • ****
  • Posts: 761
Re: 67.5 mm =cc??
« Reply #29 on: November 28, 2019, 01:42:25 PM »
more pics. The case is from an old 71 stock engine and the cylinders fit with no grinding.
Logged
Analog mind in a digital world..

Offline lash

  • Expert
  • ****
  • Posts: 761
Re: 67.5 mm =cc??
« Reply #30 on: November 28, 2019, 01:45:14 PM »
more...
Logged
Analog mind in a digital world..

Offline BPellerine

  • Master
  • *****
  • Posts: 2,222
Re: 67.5 mm =cc??
« Reply #31 on: November 28, 2019, 02:01:40 PM »
then they are stepped sleeves as Frank said,I think 67.5 is the limit for those sleeves so they are a one shot deal,no more overbore.bill
Logged
1978 CB 750K ard and webers
another anfob

Offline 754

  • Really Old Timer ...
  • *******
  • Posts: 29,058
Re: 67.5 mm =cc??
« Reply #32 on: November 28, 2019, 03:24:21 PM »
 Looks a lot like a 77 or 78 F head. Look on the top back of head for number between 2 and 3 cylinder, it should say 410 or another number.
Logged
Maker of the WELDLESS 750 Frame Kit
dodogas99@gmail.com
Kelowna B.C.       Canada

My next bike will be a ..ANFOB.....

It's All part of the ADVENTURE...

73 836cc.. Green, had it for 3 decades!!
Lost quite a few CB 750's along the way

Offline PeWe

  • Really Old Timer ...
  • *******
  • Posts: 15,575
  • Bike almost back to the 70's 2015
Re: 67.5 mm =cc??
« Reply #33 on: November 28, 2019, 08:46:00 PM »
Head ported too?
« Last Edit: November 28, 2019, 08:52:06 PM by PeWe »
Logged
CB750 K6-76  970cc (Earlier 1005cc JMR Billet block on the shelf waiting for a comeback)
CB750 K2-75 Parts assembled to a stock K2

Updates of the CB750 K6 -1976
http://forums.sohc4.net/index.php/topic,180468.msg2092136.html#msg2092136
The billet block build thread
http://forums.sohc4.net/index.php/topic,49438.msg1863571.html#msg1863571
CB750 K2 -1975  build thread
http://forums.sohc4.net/index.php/topic,168243.msg1948381.html#msg1948381
K2 engine build thread. For a complete CB750 -75
http://forums.sohc4.net/index.php/topic,180088.msg2088008.html#msg2088008
Carb jetting, a long story Mikuni TMR32
http://forums.sohc4.net/index.php/topic,179479.msg2104967.html#msg2104967

Offline lash

  • Expert
  • ****
  • Posts: 761
Re: 67.5 mm =cc??
« Reply #34 on: November 29, 2019, 06:39:12 AM »
Says 410. Dont know what a ported head looks like but this is no.2 intake..
Logged
Analog mind in a digital world..

Offline Old Scrambler

  • My CB750K3 has been in 39 States & 5 Provinces
  • Old Timer
  • ******
  • Posts: 3,810
Re: 67.5 mm =cc??
« Reply #35 on: November 29, 2019, 07:12:36 AM »
Looks like it was 'cleaned-up' but not really ported..........Is there any machining to the chamber?
Logged
Dennis in Wisconsin
'64 Triumph Cub & '74 Honda CB750 Bonneville Salt Flats AMA Record Holder (6)
CB750 Classic Bonneville Racer thread - http://forums.sohc4.net/index.php/topic,135473.0.html
'63 CL72 Project(s)
'66 CL77 Red
'67 Triumph T100C
'73 750K3 Owned since New
'77 750F2 Cafe Project
2020 ROYAL ENFIELD Himalayan

Offline Jerry Rxman Griffin aka MuthaF'er

  • This MuthaF'er is getting to be a
  • Really Old Timer ...
  • *******
  • Posts: 14,912
  • Bought her new 4/75
Re: 67.5 mm =cc??
« Reply #36 on: November 29, 2019, 07:57:08 AM »
Good start on a HP engine. Big pistons and big valves. Big cam?
Logged
As of today 3/13/2012 my original owner 75 CB750F has made it through 3 wives, er EX-wives. Free at last.  ;-)

Offline lash

  • Expert
  • ****
  • Posts: 761
Re: 67.5 mm =cc??
« Reply #37 on: November 29, 2019, 08:22:18 AM »
I never got the valves or a cam with it. I’m not really interested in building a big power engine, these just came with the package.
My stock bikes are fast enough!
Logged
Analog mind in a digital world..

Offline Terry in Australia

  • Really Old Timer ...
  • *******
  • Posts: 33,321
  • So, what do ya wanna talk about today?
Re: 67.5 mm =cc??
« Reply #38 on: November 29, 2019, 02:31:40 PM »
Yeah, the F2 head is no real performance improvement really as the negatives outweigh the positives. ;D
Logged
I was feeling sorry for myself because I couldn't afford new bike boots, until I met a man with no legs.

So I said, "Hey mate, you haven't got any bike boots you don't need, do you?"

"Crazy is a very misunderstood term, it's a fine line that some of us can lean over and still keep our balance" (thanks RB550Four)
Pages: 1 [2]  All   Go Up
« previous next »