« previous next »
Pages: [1]   Go Down

Author Topic: 1975 CB750 Cracked Engine Case...PLEASE HELP.  (Read 3149 times)

0 Members and 1 Guest are viewing this topic.

Offline Fenix500

  • Full Member
  • *
  • Posts: 15
  • 1975 Honda CB750 - Cafe Racer
1975 CB750 Cracked Engine Case...PLEASE HELP.
« on: November 09, 2009, 03:17:48 PM »
Hey guys,

Well...as fate would have it as I was about to sell my 1975 Honda CB750 Cafe Racer  --  somehow, someway, someone cracked the lower engine case next to the chain gear.
Not sure how this happened I have my suspicions about the last rider  (it wasn't me). Regardless, I need to fix this. First attempt is the case. Can one of you fine gentlemen (or Ladies) tell me if a 1975 CB750F and K use the same engine case? If not what models and years are comparable?

I would really appreciate ANY and ALL input on this disaster.

Thanks,
Fenix
Logged
"You can't depend on your eyes when your imagination is out of focus."

Offline B.O.X.N.I.F.E.

  • The Stumped
  • Expert
  • ****
  • Posts: 1,137
Re: 1975 CB750 Cracked Engine Case...PLEASE HELP.
« Reply #1 on: November 09, 2009, 03:23:32 PM »
Post a pic. There's little a capable welder in a reputable shop can't handle.
Logged
1974 CB550

32 days and 5,536 miles on a CB550...

http://kerncountykid.blogspot.com/

and a couple years later, 38 days and 9,102 miles...

Forever West

... and all of it in a 4 mintue video

<a href="Not a valid vimeo URL">WWYY?[/url]

Offline Terry in Australia

  • Really Old Timer ...
  • *******
  • Posts: 33,611
  • So, what do ya wanna talk about today?
Re: 1975 CB750 Cracked Engine Case...PLEASE HELP.
« Reply #2 on: November 09, 2009, 03:39:08 PM »
Yeah, don't panic mate, I've seen CB750 cases damaged by thrown chains repaired with epoxy resin and JB weld, and have stayed oil tight for the rest of their lives, so unless you've got a gaping hole there, you can probably fix it today with little effort.

To answer your question though, CB750F/F1 cases will fit fine. Cheers, Terry. ;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)

Offline CycleRanger

  • No comment about being an
  • Really Old Timer ...
  • *******
  • Posts: 5,801
  • Central Texas Shop Manual Advocate
Re: 1975 CB750 Cracked Engine Case...PLEASE HELP.
« Reply #3 on: November 09, 2009, 04:18:59 PM »
See this recent thread.

http://forums.sohc4.net/index.php?topic=60825.0

I just had the same experience.  I re-repaired my case with a fresh coat of JB Weld and while I haven't run the motor yet it looks to me like it turned out pretty good.
Logged
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 Fenix500

  • Full Member
  • *
  • Posts: 15
  • 1975 Honda CB750 - Cafe Racer
Re: 1975 CB750 Cracked Engine Case...PLEASE HELP.
« Reply #4 on: November 10, 2009, 03:58:46 PM »
Well guys.

Thanks for all the input. Unfortunately, the damn thing cracked where the two parts of the case meet. I'll never get it to seal correctly...%$#@!
So...I'm just throwing out there the hope that someone has a 1970's CB750 SOHC Engine in their barn...and it still has compression and...said person(s) want to sell it to me REAL cheap...like $150-200.

If anyone fits this description PLEASE email me with details.

Thanks. And have a good evening Gents.
--Fenix

Logged
"You can't depend on your eyes when your imagination is out of focus."

Offline CycleRanger

  • No comment about being an
  • Really Old Timer ...
  • *******
  • Posts: 5,801
  • Central Texas Shop Manual Advocate
Re: 1975 CB750 Cracked Engine Case...PLEASE HELP.
« Reply #5 on: November 10, 2009, 04:08:37 PM »
Post a photo of the crack!
Logged
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 Fenix500

  • Full Member
  • *
  • Posts: 15
  • 1975 Honda CB750 - Cafe Racer
Re: 1975 CB750 Cracked Engine Case...PLEASE HELP.
« Reply #6 on: November 10, 2009, 04:13:43 PM »
Ok. I'll have to post some pix tomorrow it's down at the shop.

Thanks.
Logged
"You can't depend on your eyes when your imagination is out of focus."

Offline Toxic

  • Expert
  • ****
  • Posts: 1,200
Re: 1975 CB750 Cracked Engine Case...PLEASE HELP.
« Reply #7 on: November 10, 2009, 04:28:41 PM »
more importantly is it leaking, if so how bad.

I've seen some major holes as well as cracks repaired with JB Weld.

Unless oil is pouring out, I bet it can be fixed.
Logged

Offline 754

  • Really Old Timer ...
  • *******
  • Posts: 29,046
Re: 1975 CB750 Cracked Engine Case...PLEASE HELP.
« Reply #8 on: November 10, 2009, 09:12:18 PM »


 Just say NO... to CRACK... :o






 that is what my kids told me they learned in school....  ;D
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
Pages: [1]   Go Up
« previous next »