Author Topic: Let's Go BIG 1000cc or more  (Read 7079 times)

0 Members and 1 Guest are viewing this topic.

Offline gschuld

  • Master
  • *****
  • Posts: 2,346
Re: Let's Go BIG 1000cc or more
« Reply #25 on: November 29, 2015, 05:57:17 PM »
For those who would enjoy some light reading from the archives: 

December, 1973, Big Bike magazine:  (3yrs before the big "Cobra" article came out)

Enjoy,

George
« Last Edit: November 29, 2015, 06:05:12 PM by gschuld »

Offline gschuld

  • Master
  • *****
  • Posts: 2,346
Re: Let's Go BIG 1000cc or more
« Reply #26 on: November 29, 2015, 05:58:12 PM »
2nd page

Offline gschuld

  • Master
  • *****
  • Posts: 2,346
Re: Let's Go BIG 1000cc or more
« Reply #27 on: November 29, 2015, 05:58:57 PM »
3rd

Offline gschuld

  • Master
  • *****
  • Posts: 2,346
Re: Let's Go BIG 1000cc or more
« Reply #28 on: November 29, 2015, 05:59:42 PM »
4th

Offline gschuld

  • Master
  • *****
  • Posts: 2,346
Re: Let's Go BIG 1000cc or more
« Reply #29 on: November 29, 2015, 06:00:16 PM »
5th

Offline gschuld

  • Master
  • *****
  • Posts: 2,346
Re: Let's Go BIG 1000cc or more
« Reply #30 on: November 29, 2015, 06:00:55 PM »
Last

Offline Bill/BentON Racing

  • Really Old Timer ...
  • *******
  • Posts: 6,725
  • Ex Honda Service Manager, Cert. Honda Tech - Racer
    • BentON Racing
Re: Let's Go BIG 1000cc or more
« Reply #31 on: November 29, 2015, 06:42:05 PM »
I tried @ 5:30. It just moves from one compression stroke to the next! Crazy. It was laughing at me!! ;D,Bill
BentON Racing Website
OEM Parts | Service | Custom Builds
BentON Racing Facebook
Over 35 years of experience working on vintage motorcycles, with a speciality in Honda SOHC/4 with a focus on the CB750 and other models as well from 1966 - 1985.
______________________________________
1993 HRC RS125 | 1984 NS400R | 1974 Honda CB750/836cc (Calendar Girl) | 1972 CB 500/550 Yoshi Kitted 590cc | 1965 Honda CB450 Black Bomber | 1972 Suzuki T350 | 1973 88cc | Z50/Falcons Pit Bike | 1967 CA100| 1974 CB350 (400F motor)...and more.
______________________________________
See our latest build 'Captain Marvel' CLICK HERE

Offline gschuld

  • Master
  • *****
  • Posts: 2,346
Re: Let's Go BIG 1000cc or more
« Reply #32 on: November 30, 2015, 04:03:46 AM »
Billy,

Are those 73mm pistons 12.5:1 in the Cobra motor?

George

Offline BPellerine

  • Master
  • *****
  • Posts: 2,222
Re: Let's Go BIG 1000cc or more
« Reply #33 on: November 30, 2015, 10:25:11 AM »
I tried @ 5:30. It just moves from one compression stroke to the next! Crazy. It was laughing at me!! ;D,Bill
you got some heavy compression there Bill!!! how did it sound when it laughed.haha billp
1978 CB 750K ard and webers
another anfob

Offline Jerry Rxman Griffin aka MuthaF'er

  • This MuthaF'er is getting to be a
  • Really Old Timer ...
  • *******
  • Posts: 14,902
  • Bought her new 4/75
Re: Let's Go BIG 1000cc or more
« Reply #34 on: November 30, 2015, 06:59:25 PM »
Curious minds want to know. OK George, here you go ;-) No drooling or begging allowed!

Doesn't this make this a real 1080 and not a 1055/1060?





















Sleeve thickness is 1.2mm. Kinda thin to win.




« Last Edit: November 30, 2015, 07:13:15 PM by Jerry Rxman Griffin aka MuthaF'er »
As of today 3/13/2012 my original owner 75 CB750F has made it through 3 wives, er EX-wives. Free at last.  ;-)

Offline Bill/BentON Racing

  • Really Old Timer ...
  • *******
  • Posts: 6,725
  • Ex Honda Service Manager, Cert. Honda Tech - Racer
    • BentON Racing
Re: Let's Go BIG 1000cc or more
« Reply #35 on: November 30, 2015, 08:16:54 PM »
Last time I did the math, I believe it takes 73.75 to actually get 1080 cc, send all that this way,  Bill
BentON Racing Website
OEM Parts | Service | Custom Builds
BentON Racing Facebook
Over 35 years of experience working on vintage motorcycles, with a speciality in Honda SOHC/4 with a focus on the CB750 and other models as well from 1966 - 1985.
______________________________________
1993 HRC RS125 | 1984 NS400R | 1974 Honda CB750/836cc (Calendar Girl) | 1972 CB 500/550 Yoshi Kitted 590cc | 1965 Honda CB450 Black Bomber | 1972 Suzuki T350 | 1973 88cc | Z50/Falcons Pit Bike | 1967 CA100| 1974 CB350 (400F motor)...and more.
______________________________________
See our latest build 'Captain Marvel' CLICK HERE

Offline Jerry Rxman Griffin aka MuthaF'er

  • This MuthaF'er is getting to be a
  • Really Old Timer ...
  • *******
  • Posts: 14,902
  • Bought her new 4/75
Re: Let's Go BIG 1000cc or more
« Reply #36 on: November 30, 2015, 08:48:46 PM »
Buncha posers!! There you go begging again LOL. I've already denied George's request. NOS to boot ;-)

Wonder if these are the same as in your Cobra Bill?
As of today 3/13/2012 my original owner 75 CB750F has made it through 3 wives, er EX-wives. Free at last.  ;-)

Offline Bill/BentON Racing

  • Really Old Timer ...
  • *******
  • Posts: 6,725
  • Ex Honda Service Manager, Cert. Honda Tech - Racer
    • BentON Racing
Re: Let's Go BIG 1000cc or more
« Reply #37 on: December 01, 2015, 04:46:00 AM »
Why, send them to me and I'll gladly compare!
BentON Racing Website
OEM Parts | Service | Custom Builds
BentON Racing Facebook
Over 35 years of experience working on vintage motorcycles, with a speciality in Honda SOHC/4 with a focus on the CB750 and other models as well from 1966 - 1985.
______________________________________
1993 HRC RS125 | 1984 NS400R | 1974 Honda CB750/836cc (Calendar Girl) | 1972 CB 500/550 Yoshi Kitted 590cc | 1965 Honda CB450 Black Bomber | 1972 Suzuki T350 | 1973 88cc | Z50/Falcons Pit Bike | 1967 CA100| 1974 CB350 (400F motor)...and more.
______________________________________
See our latest build 'Captain Marvel' CLICK HERE

Offline gschuld

  • Master
  • *****
  • Posts: 2,346
Re: Let's Go BIG 1000cc or more
« Reply #38 on: December 01, 2015, 07:15:56 AM »
Nice stuff Jerry.  You might have to build something with that someday ;)  Interesting piston design.  I have never seen a big bore piston that was cast and machined like that.  Venolia was the exclusive piston maker for RC until about 1974, then Arias took over.  The RC Arias pistons in the later 70s that I have or have seen all had specific markings cast in the mold in the underside of the piston.  Like the RC 70s below:

Your pistons have a very different shape and casting design.  Frankie has a 1989 vintage Arias set of 73s and his are similar to their earlier RC versions.  I wonder what the deal is with those 73.75s.  Perhaps Arias used a totally different piston blank for custom piston sizes beyond 73mm.  Maybe Arias didn't make them...

Any idea when these pistons were originally purchased?

George

Offline kmb69

  • Master
  • *****
  • Posts: 2,041
Re: Let's Go BIG 1000cc or more
« Reply #39 on: December 01, 2015, 07:31:33 AM »
.....
Doesn't this make this a real 1080 and not a 1055/1060?
.....
Almost.
73.75 Pistons Cylinders = 1076.50
74.00 Pistons Cylinders = 1083.81

Fixed it. Thanks, Turbo.
« Last Edit: December 01, 2015, 10:33:13 AM by kmb69 »

Offline TurboD

  • Hot Shot
  • ***
  • Posts: 680
Re: Let's Go BIG 1000cc or more
« Reply #40 on: December 01, 2015, 08:03:56 AM »
What happens when we add .0025 clearance in each cylinder... ;D ;D

Offline teebee67

  • Enthusiast
  • **
  • Posts: 162
Re: Let's Go BIG 1000cc or more
« Reply #41 on: December 01, 2015, 08:59:16 AM »
Can anyone tell me the actual stroke of the RC Eng big bore kits? I have one fitted and we are required to provide the stroke in mm for noise testing.
I'm only old on the outside.

Offline gschuld

  • Master
  • *****
  • Posts: 2,346
Re: Let's Go BIG 1000cc or more
« Reply #42 on: December 01, 2015, 09:10:11 AM »
63mm is stock.  Plus 1/4"

George

Offline Jerry Rxman Griffin aka MuthaF'er

  • This MuthaF'er is getting to be a
  • Really Old Timer ...
  • *******
  • Posts: 14,902
  • Bought her new 4/75
Re: Let's Go BIG 1000cc or more
« Reply #43 on: December 01, 2015, 09:37:55 AM »
George, not too sure of the background. I picked these up a number of years ago from a member in Texas.

It IS an RC box, that I am sure of ;-)
As of today 3/13/2012 my original owner 75 CB750F has made it through 3 wives, er EX-wives. Free at last.  ;-)

Offline teebee67

  • Enthusiast
  • **
  • Posts: 162
Re: Let's Go BIG 1000cc or more
« Reply #44 on: December 01, 2015, 11:03:14 AM »
Thanks George - that would work out at 6.35mm = 69.35 then?
I'm only old on the outside.

Offline gschuld

  • Master
  • *****
  • Posts: 2,346
Re: Let's Go BIG 1000cc or more
« Reply #45 on: December 01, 2015, 12:03:49 PM »
Sounds about right.

George

Offline KayOne

  • Enthusiast
  • **
  • Posts: 190
Re: Let's Go BIG 1000cc or more
« Reply #46 on: December 01, 2015, 03:29:29 PM »
Not to highjack the thread, but thanks for posting the Big Bike article George. The pictures verify that the header that came on my K1 Chopper is a RC :)
CB750 K1 restored
1979 CB750Fz - original except for exhaust, 14000km
1984 VF45F Interceptor - all original, 12000 km
1968 S90 - all original, 2100 miles
1973 H2a, Restored
1973 H1D, next project
CB750K1 (sold)
1976 KZ900 (sold)
1981 CB900F (under restoration)
2015 Yamaha FJ09, my appliance rider

Offline gschuld

  • Master
  • *****
  • Posts: 2,346
Re: Let's Go BIG 1000cc or more
« Reply #47 on: December 01, 2015, 03:41:14 PM »
No problem.  RC pipes have a unique 1/3 2/4 collector pattern and gentler than typical bends in the header pipes.  The early ones did not have any ID markings on them.

Glad you liked the article.  It's all about big bore motors ;)

George

Offline bear

  • Vale Bill McIntosh ......"illegitimi non carborundum"
  • Old Timer
  • ******
  • Posts: 2,575
  • Leeton in Australia
Re: Let's Go BIG 1000cc or more
« Reply #48 on: December 02, 2015, 01:29:55 AM »
A bit more big bore stuff for you.
These barrels where cast for us many years ago.
No oil leaks with these. ;)
The older I get the faster I was.

Offline Retro Rocket

  • Eggs are hard due too a
  • Really Old Timer ...
  • *******
  • Posts: 19,279
  • ROCK & ROLL
Re: Let's Go BIG 1000cc or more
« Reply #49 on: December 02, 2015, 03:46:58 AM »
A bit more big bore stuff for you.
These barrels where cast for us many years ago.
No oil leaks with these. ;)

Good looking Block there Brian...  If you don't mind me asking, how many kidneys did they cost you... ;)
750 K2 1000cc
750 F1 970cc
750 Bitsa 900cc
If You can't fix it with a hammer, You've got an electrical problem.