Author Topic: 750 K0 honda Sandcast lower case, Diecast upper???  (Read 4448 times)

0 Members and 1 Guest are viewing this topic.

Offline wdammit75

  • Full Member
  • *
  • Posts: 12
750 K0 honda Sandcast lower case, Diecast upper???
« on: November 06, 2009, 05:15:44 PM »
I'm the guy i the post " best 100 bucks a guy could spend". I was looking at the bike again today (K0 750) and there is a distinct difference in the finish and surface between my upper and lower case halves. The upper is clearly diecast, very smooth and no number stamped. The bottom, on the other hand is quite rough in finish. Is it even possible to have them bolted together?
  I do have pictures and will post them as sonn as I get home.  If it helps, my clutch cover is held on by 10 screws. My oil pan has 10 bolts as well. Maybe by some of those details someone could tell me if it's even possible.

Looking at the motor, the top case is the only thing out of place, color and surface wise.

 Can someone please let me know what you think/know?

Thank you

Offline CycleRanger

  • No comment about being an
  • Really Old Timer ...
  • *******
  • Posts: 5,442
  • Central Texas Shop Manual Advocate
Re: 750 K0 honda Sandcast lower case, Diecast upper???
« Reply #1 on: November 06, 2009, 05:32:29 PM »
More pictures would us make better guesses.  :D
Do you have a copy of the Honda Shop Manual or Parts List for your bike? Get one here:
https://www.honda4fun.com/materiale/documentazione-tecnica
CB750K5        '79 XL250s     CL350K3
CB750K3        '76 XS650      '76 CJ360T

Offline Magpie

  • Old Timer
  • ******
  • Posts: 3,303
Re: 750 K0 honda Sandcast lower case, Diecast upper???
« Reply #2 on: November 06, 2009, 05:36:34 PM »
I have a sandcast motor and the clutch cover has 9 screws holding it on. My later motors, K0 and K1) have 10. The one just below where the clutch cable goes into it is missing on the sandcast ones. Sounds like an interesting life for that motor.
Cliff.

Offline wdammit75

  • Full Member
  • *
  • Posts: 12
Re: 750 K0 honda Sandcast lower case, Diecast upper???
« Reply #3 on: November 06, 2009, 05:47:51 PM »
Wish it was closer. This is a pic from my last post.

Offline wdammit75

  • Full Member
  • *
  • Posts: 12
Re: 750 K0 honda Sandcast lower case, Diecast upper???
« Reply #4 on: November 06, 2009, 05:49:43 PM »
Another

Offline Simpson

  • I ain't no
  • Expert
  • ****
  • Posts: 791
  • Aged to perfection
Re: 750 K0 honda Sandcast lower case, Diecast upper???
« Reply #5 on: November 06, 2009, 07:10:02 PM »
Sounds like a sandcast that had the case broke by a drive chain. I would think a dealer replaced the upper side with a diecast.
1970 CB750 K0
1975 CL/CB 360 Mix

Offline Don R

  • My Sandcast is a
  • Really Old Timer ...
  • *******
  • Posts: 19,972
  • Saver of unloved motorcycles.
Re: 750 K0 honda Sandcast lower case, Diecast upper???
« Reply #6 on: November 07, 2009, 04:29:18 PM »
I think I saw one a couple weeks ago. The owner mentioned it and I didn't realize what he was talking about until I read this. Is yours a high serial number sandcast? Like 10065xx or higher? He has known his bike since new and it has never been apart. It has all the clutch bolts too.
« Last Edit: November 07, 2009, 04:32:46 PM by Don R »
No matter how many times you paint over a shadow, it's still there.
 CEO at the no kill motorcycle shop.
 You don't need a weatherman to know which way the wind blows.

Offline Terry in Australia

  • Really Old Timer ...
  • *******
  • Posts: 33,321
  • So, what do ya wanna talk about today?
Re: 750 K0 honda Sandcast lower case, Diecast upper???
« Reply #7 on: November 08, 2009, 04:10:32 AM »
Well it's the lower sandcast case that has one less clutch cover screw, so no, your lower case is die cast. Typically, the lower case is a "rougher" casting than the top case, because you don't see much of it.

If you've got unstamped cases, (and presuming your K0 is an early sandcast build) your engine was probably a victim of a busted drive chain smashing your cases, this was pretty common with early K0's. Cheers, Terry. ;D   
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)

Offline wdammit75

  • Full Member
  • *
  • Posts: 12
Re: 750 K0 honda Sandcast lower case, Diecast upper???
« Reply #8 on: November 08, 2009, 06:13:40 AM »
Well heres some more pics, maybe I was just being wishful!!!


Offline wdammit75

  • Full Member
  • *
  • Posts: 12
Re: 750 K0 honda Sandcast lower case, Diecast upper???
« Reply #9 on: November 08, 2009, 06:15:43 AM »
1

Offline Terry in Australia

  • Really Old Timer ...
  • *******
  • Posts: 33,321
  • So, what do ya wanna talk about today?
Re: 750 K0 honda Sandcast lower case, Diecast upper???
« Reply #10 on: November 08, 2009, 03:28:13 PM »
Yep, my diecast K0 bottom case looks pretty much like that one. Cheers, Terry. ;D
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)

Offline bryanj

  • Really Old Timer ...
  • *******
  • Posts: 14,044
  • CB500 Number 1000036
Re: 750 K0 honda Sandcast lower case, Diecast upper???
« Reply #11 on: November 09, 2009, 08:34:36 AM »
You could/can not buy a new half case and no dealer who wanted to stay in business would fit just one half due to machining tolerances
Semi Geriatric ex-Honda mechanic and MOT tester (UK version of annual inspection). Garage full of "projects" mostly 500/4 from pre 73 (no road tax in UK).

Remember "Its always in the last place you look" COURSE IT IS YOU STOP LOOKIN THEN!

Offline 754

  • Really Old Timer ...
  • *******
  • Posts: 29,058
Re: 750 K0 honda Sandcast lower case, Diecast upper???
« Reply #12 on: November 09, 2009, 09:02:30 AM »
IIRC my 10,XXX cases have batch numbers at the rear.. sorta where the carb hoses hang down.

 If you are taking the swingarm off for any reason, you could look.
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 MCRider

  • Such is the life of a
  • Really Old Timer ...
  • *******
  • Posts: 14,376
  • Today's Lesson: One good turn deserves another.
Re: 750 K0 honda Sandcast lower case, Diecast upper???
« Reply #13 on: November 09, 2009, 09:16:18 AM »
You could/can not buy a new half case and no dealer who wanted to stay in business would fit just one half due to machining tolerances
that's what i was thinking. The line bore for the crankshaft bearings has to be dead on and matched, case to case.
Ride Safe:
Ron
1988 NT650 HawkGT;  1978 CB400 Hawk;  1975 CB750F -Free Bird; 1968 CB77 Super Hawk -Ticker;  Phaedrus 1972 CB750K2- Build Thread
"Sometimes the light's all shining on me, other times I can barely see, lately it appears to me, what a long, strange trip its been."

Offline 754

  • Really Old Timer ...
  • *******
  • Posts: 29,058
Re: 750 K0 honda Sandcast lower case, Diecast upper???
« Reply #14 on: November 09, 2009, 09:44:23 AM »
That is  true, but even on here I have heard of mismatched cases several times...

 Did the guy say the case was dealer installed, or did he get it done by a "mechanic" ? If that happened and was a mismatch, but turned over ok, it may go 5K or 50 K. If the owner was aware there was case problems, and started worrying about it.. he may have stopped riding it (cause he did not trust it).. and then sold it cheap..

 At any rate you wont know till you find batch numbers or measure the cases..... so if it runs, use it..

 And keep an eye out for early diecast cases.
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 wdammit75

  • Full Member
  • *
  • Posts: 12
Re: 750 K0 honda Sandcast lower case, Diecast upper???
« Reply #15 on: November 09, 2009, 11:31:19 AM »
I have spooken with the only owners before me, including the one who bought it new. They both said the bike was never returned to the dealership for anything. This is the way the bike came, period. The reaqson the guy parked it was that his brother-in-law was killed in a motorcycle crash shortly after he bought it. His wife DIDN'T want him riding anymore.

So what am I looking for in the way of batch numbers??? What about measuring the cases, from where to where? What are the specs for diecast vs. sandcast?  Any help??

Offline Terry in Australia

  • Really Old Timer ...
  • *******
  • Posts: 33,321
  • So, what do ya wanna talk about today?
Re: 750 K0 honda Sandcast lower case, Diecast upper???
« Reply #16 on: November 09, 2009, 03:15:02 PM »
That's interesting, but I doubt that a bike with no engine numbers made it out of the factory, got past a dealer, and escaped the notice of the DMV. When did the original owner buy it?

I bought my "new" 1975 CB750F in March 1978, it was still sitting in the crate, the F/F1 was a particularly unattractive bike and the dealers here couldn't move them, so I bought it at a heavily discounted price.

Maybe your K0 was a "shop bike" ("Demonstration Vehicle") that busted the original stamped cases very early in it's life, and was repaired with unstamped cases before the original owner purchased it? Cheers, Terry. ;D
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)

Offline 754

  • Really Old Timer ...
  • *******
  • Posts: 29,058
Re: 750 K0 honda Sandcast lower case, Diecast upper???
« Reply #17 on: November 09, 2009, 07:49:45 PM »
Those are probably day , and month , and maybe year numbers..common on diecast parts.

 If you pulled the swingarm, and looked at the split of the cases.. (my early diecast has these, cant say I noticed them on later cases) there may be a number above and below the split.. this will mean they were machined together and are matched cases.
 To actually measure the bearing bores, you would be measuring in ten thousanths of an inch, unless it was real bad (probably would not live long)

BTW there is at least one difference between early diecast and say 72s.... if you want to be correct..
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