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Lower crankcase hole

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davehampton
honda305.com Member
Posts: 10
Joined: Tue Sep 09, 2014 8:18 am
Location: Marshfield, MO USA

Lower crankcase hole

Post by davehampton » Wed Nov 05, 2014 3:15 pm

I am restoring a 1966 CB77 Superhawk. The original bottom crankcase on the bike has a broken motormount and some cracking so I bought another one on ebay for a 1965 model that I was told would work for my bike. After examining both cases I discovered a hole that was machined into my bike's (1966) case on the left rear behind the crank where the oil bath is located. The hole is machined on the outside of the 1965 replacement case, but does not continue through into the interior. I've attached photos of the two cases for review. Does anyone know if I will be able to use the replacement case, and do you know what the hole is for?
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1966pic.jpg
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jensey
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Posts: 384
Joined: Sun Jun 17, 2012 3:34 am
Location: Netherlands

Post by jensey » Thu Nov 06, 2014 2:41 am

Hi,

Question in the first post, no introduction, no location provided.
Could you please give a proper introduction, and give your location ?

Some people here could think this way:

If you're to lazy to introduce yourself and fill in your location, we are to buzy to answer your question.

Jensen
assembly of Japanese motorcycles requires great peace of mind (Pirsig)

davehampton
honda305.com Member
Posts: 10
Joined: Tue Sep 09, 2014 8:18 am
Location: Marshfield, MO USA

Engine Crankcase Question

Post by davehampton » Thu Nov 06, 2014 9:53 am

Hi Jensey,
I can assure you that I am not lazy (anyone doing a frame-up restoration on a vintage bike can attest to that); however I am new to this forum and do not understand all its complexities. For instance, I assumed my location would automatically post with my question.

Anyway, here is some info:
I'm restoring a 1966 CB77 that I recently acquired and I am located in Marshfield, Missouri in the United States. I would appreciate any help with the question I posted regarding the crankcase.
Thanks much,
Dave

LOUD MOUSE
honda305.com Member
Posts: 7817
Joined: Mon Aug 15, 2005 8:23 am
Location: KERRVILLE, TEXAS

Re: Lower crankcase hole

Post by LOUD MOUSE » Thu Nov 06, 2014 10:16 am

Look at the other side.
Could it be for the shift shaft end?. ...lm
davehampton wrote:I am restoring a 1966 CB77 Superhawk. The original bottom crankcase on the bike has a broken motormount and some cracking so I bought another one on ebay for a 1965 model that I was told would work for my bike. After examining both cases I discovered a hole that was machined into my bike's (1966) case on the left rear behind the crank where the oil bath is located. The hole is machined on the outside of the 1965 replacement case, but does not continue through into the interior. I've attached photos of the two cases for review. Does anyone know if I will be able to use the replacement case, and do you know what the hole is for?

davehampton
honda305.com Member
Posts: 10
Joined: Tue Sep 09, 2014 8:18 am
Location: Marshfield, MO USA

Post by davehampton » Thu Nov 06, 2014 11:31 am

Hi Loud Mouse,
You're right, the opening is for the shaft of the shifter arm (I should of made that clearer on my original post).
I guess my real question is: "Since the hole (or opening) doesn't go completely through the the 1965 case can I still use it as is or do I need to machine the hole out? I'm wondering if the end of the shaft benefits from an oil bath and may be why it's different on the 1966.
Again, I appreciate any input from you experts.
thanks again

48lesco
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Joined: Tue Mar 06, 2007 1:45 pm
Location: Olmsted Twp, Ohio

Post by 48lesco » Fri Nov 07, 2014 5:16 pm

My '64 (engine 108333) has the through-hole which doesn't really lend any consistency to the matter. If possible, always go by the engine numbers. The titles for these bikes were dated in the year sold, not necessarily the year produced. You have no way of knowing what series the ebay case is unless you got the top half too and it was the original top half that went with the bottom half etc. etc... That shaft is in an oil bath from the clutch side anyway, and there's not a lot of speed or load so I really wouldn't give it a second thought... One more piece of information is that the part number for that case didn't change after engine number 311979 (produced in '63). Not sure what the variations were prior to that (too lazy to research it -ha). Good luck
-48

davehampton
honda305.com Member
Posts: 10
Joined: Tue Sep 09, 2014 8:18 am
Location: Marshfield, MO USA

Post by davehampton » Fri Nov 07, 2014 6:09 pm

Hi 48lesco,
Thanks for the message, especially the info regarding the fact that the case didn't change after 1963. Fortunately, I was able to get the serial number from the person who owned the case so I know for a fact it was a 1965 model. I communicated with Tim at Classic Honda Restoration and he said the hole not going all the way through the case should not be a problem.
Thanks everyone for the input, it looks like I'll be fine with the replacement case.

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