Need your help please - oil leak!

If it's broken or just needs tweaked

Moderators: Volker_P, tidd650

User avatar
MrRiver
Posts: 7
Joined: Fri Apr 08, 2016 8:32 am
Location: Ireland

Need your help please - oil leak!

Postby MrRiver » Mon Apr 11, 2016 4:11 pm

Hi guys
I'm the proud owner of a Honda CB650 Nighthawk from 1983, I picked it up two weeks ago.
My knowledge of engines and bikes is very limited so I would appreciate some help with diagnosing an oil leak.
I'll be honest and say I'm not even sure what you call the part of the engine the oil appears to be leaking from, from looking online I think it's between the alternator and engine on the left hand side of the bike. I have included photos.
I really appreciate any help you can give me, do I need a new gasket? What is that small hole the oil seems to be leaking from?
Thank you in advance.
Attachments
20160409_111535.jpg
20160409_111535.jpg (2.97 MiB) Viewed 19151 times
20160408_103737.jpg
20160408_103737.jpg (3.64 MiB) Viewed 19151 times
20160408_100828.jpg
20160408_100828.jpg (3.89 MiB) Viewed 19151 times

User avatar
Folsoml
Posts: 1634
Joined: Sat Apr 07, 2012 9:02 pm
Location: North Florida

Re: Need your help please - oil leak!

Postby Folsoml » Mon Apr 11, 2016 4:35 pm

Let me start by saying I am not very familiar with the Nighthawk layout.

That being said, based on looking at the parts fiche for this bike, I do not believe there should be oil behind that cover. All the oil should be kept out of there by an oil seal on the alternator shaft. If oil is leaking out from this cover, I'd wager that oil seal needs replacing.
Have a problem with your CB650? Have a technical question? Click here!


My Current Bikes: 2005 HD FLHTCUI Electra Glide Ultra Classic, 2007 Yamaha Vino,

navydad
Posts: 20
Joined: Wed Dec 16, 2015 9:00 pm
Location: Ohio
Contact:

Re: Need your help please - oil leak!

Postby navydad » Mon Apr 11, 2016 5:20 pm

+1 on the leaking seal. Doesn't look like a difficult job.

User avatar
MrRiver
Posts: 7
Joined: Fri Apr 08, 2016 8:32 am
Location: Ireland

Re: Need your help please - oil leak!

Postby MrRiver » Tue Apr 12, 2016 2:38 am

Thanks for the response guys, everything helps as this is all new to me, I have not a clue about engines.

From what you said do you think the oil seal (number 12 in this alternator schematic) is the part I need? Maybe the o-ring at number 13 as well?

http://www.cmsnl.com/honda-cb650sc-nigh ... ml#results

Cheers again

User avatar
MrRiver
Posts: 7
Joined: Fri Apr 08, 2016 8:32 am
Location: Ireland

Re: Need your help please - oil leak!

Postby MrRiver » Tue Apr 12, 2016 3:34 am

Here is the alternator schematic
Attachments
honda-cb650sc-nighthawk-650-1983-d-usa-alternator_bighu0192e5d10_7044.gif
honda-cb650sc-nighthawk-650-1983-d-usa-alternator_bighu0192e5d10_7044.gif (106.76 KiB) Viewed 19142 times

User avatar
Folsoml
Posts: 1634
Joined: Sat Apr 07, 2012 9:02 pm
Location: North Florida

Re: Need your help please - oil leak!

Postby Folsoml » Tue Apr 12, 2016 5:18 am

Yep. Number 12 was the one I was seeing. While you are there, might as well get the 13 as well.
Have a problem with your CB650? Have a technical question? Click here!


My Current Bikes: 2005 HD FLHTCUI Electra Glide Ultra Classic, 2007 Yamaha Vino,

User avatar
MrRiver
Posts: 7
Joined: Fri Apr 08, 2016 8:32 am
Location: Ireland

Re: Need your help please - oil leak!

Postby MrRiver » Tue Apr 12, 2016 10:53 am

Folsoml wrote:Yep. Number 12 was the one I was seeing. While you are there, might as well get the 13 as well.


Thanks Folsoml, I will order both.

navydad
Posts: 20
Joined: Wed Dec 16, 2015 9:00 pm
Location: Ohio
Contact:

Re: Need your help please - oil leak!

Postby navydad » Tue Apr 12, 2016 8:01 pm

I agree, do both while you are in there.

User avatar
MrRiver
Posts: 7
Joined: Fri Apr 08, 2016 8:32 am
Location: Ireland

Re: Need your help please - oil leak!

Postby MrRiver » Wed Apr 13, 2016 1:30 am

navydad wrote:I agree, do both while you are in there.


Yes Sir *Salutes sharply*

Permission to carry on? :)

User avatar
MrRiver
Posts: 7
Joined: Fri Apr 08, 2016 8:32 am
Location: Ireland

Re: Need your help please - oil leak!

Postby MrRiver » Thu Apr 14, 2016 8:28 am

Hi guys
I have the oil seal and o-ring changed, my first job ever on an engine and it went very well.
I used a 16 x 1.5 bolt as a flywheel puller and it done the job. Happy to say it fixed my leak was a good learning experience.
I will include some photos to help others in the same situation.

Oil seal change.jpg
Oil seal change.jpg (771.13 KiB) Viewed 19113 times

Kidonaclassicbike
Posts: 16
Joined: Wed Mar 30, 2016 7:51 am

Re: Need your help please - oil leak!

Postby Kidonaclassicbike » Thu Apr 21, 2016 3:57 pm

MrRiver wrote:Hi guys
I have the oil seal and o-ring changed, my first job ever on an engine and it went very well.
I used a 16 x 1.5 bolt as a flywheel puller and it done the job. Happy to say it fixed my leak was a good learning experience.
I will include some photos to help others in the same situation.

Oil seal change.jpg


Thanks for all the Pics and good job !

JdeP
Posts: 1
Joined: Fri Oct 01, 2021 4:41 am

Re: Need your help please - oil leak!

Postby JdeP » Sat Oct 23, 2021 7:30 am

Hi,
Thanks for sharing this! I had an identical oil leak on my 1985 CB650SC Nighthawk and with the help of this post I fixed it:)

User avatar
Volker_P
Posts: 5508
Joined: Mon Mar 06, 2006 1:53 am
Location: southern Germany

Re: Need your help please - oil leak!

Postby Volker_P » Tue Oct 26, 2021 1:47 am

Welcome here! :D

Good to have some feedback like yours from time to time as the activities in this forum became quite low in the past years.
So this forum still seems to be of some use. :)
Cosky's great (free) online manual: http://cosky0.tripod.com

forum links to common technical issues

If you really like this site and you would not like to see it vanish soon, have a look there: Urgent: Future of HondaCB650.com Forum

User avatar
MrRiver
Posts: 7
Joined: Fri Apr 08, 2016 8:32 am
Location: Ireland

Re: Need your help please - oil leak!

Postby MrRiver » Tue Oct 26, 2021 1:58 am

Yes agreed, I'm glad this could help someone, I've since sold my Nighthawk but we had some amazing adventures together, great wee bike!


Return to “Technical Discussion”

Who is online

Users browsing this forum: No registered users and 48 guests