Splitting Crankcases


Post Reply
User avatar
pouchy750
Forum Regular
Forum Regular
Posts: 41
Joined: Fri May 03, 2013 9:08 pm
Location: N.Vancouver/BC
Location: N.Vancouver/BC

Splitting Crankcases

Post by pouchy750 »

My first rebuild on a 79 CBX1000 didn't go as smooth as I thought.
There is oil pissing out from behind the engine sprocket.
I had forgotten to put the oil seal in there when the cases were apart, I didn't take the engine apart, but I should have known better.
So I ground the outside lip off the oil seal & fitted it, obviously it didn't work.
I will take the engine out & replace the seal properly.
Flipping the engine over, can you split the cases with just taking the clutch cover off?
Do I have to remove more Items? I really don't want to disturb more than necessary to cure this oil leak.
Thanks for any advise.

mike209
ICOA Member
ICOA Member
Posts: 100
Joined: Thu Dec 13, 2012 9:23 pm
Location: Long Island, NY
Location: Long Island

Re: Splitting Crankcases

Post by mike209 »

I think you have to remove the clutch and two sprockets with small chain driving oil pump, that is what I had to do last night to split the cases :shock:

daves79x
ICOA Technical Director
ICOA Technical Director
Posts: 4738
Joined: Sun Oct 01, 2006 8:05 am
Location: Knox, PA
Location: Knox, PA

Re: Splitting Crankcases

Post by daves79x »

Too bad on the oil seal. Yes, remove the clutch and oil pump drive chain/sprockets and you should be OK to split.

Dave

User avatar
pouchy750
Forum Regular
Forum Regular
Posts: 41
Joined: Fri May 03, 2013 9:08 pm
Location: N.Vancouver/BC
Location: N.Vancouver/BC

Re: Splitting Crankcases

Post by pouchy750 »

Mike209
Thanks for your response to my question.
Whilst you have your cases apart could you please measure how deep the oil seal behind the engine sprocket is located into the cases.
Is it flush with the outer side of the case or does it sit deeper?
At present mine is flush with the case & I'm not sure if this is the correct depth.
When I ground the outside location lip off the seal I didn't measure how far into the cases the seal should go.
I have a feeling it is blocking off the oil flow to the inside of the gearbox output shaft & causing the oil leak with too much pressure build up.
Thanks in advance.

daves79x
ICOA Technical Director
ICOA Technical Director
Posts: 4738
Joined: Sun Oct 01, 2006 8:05 am
Location: Knox, PA
Location: Knox, PA

Re: Splitting Crankcases

Post by daves79x »

The oil seal sits flush with the case. Did you use crankcase sealant on the outside of the seal?

Dave

User avatar
pouchy750
Forum Regular
Forum Regular
Posts: 41
Joined: Fri May 03, 2013 9:08 pm
Location: N.Vancouver/BC
Location: N.Vancouver/BC

Re: Splitting Crankcases

Post by pouchy750 »

Dave
Thanks for your response.
What sealant would you recommend?

EMS
ICOA Member
ICOA Member
Posts: 10151
Joined: Wed Mar 05, 2003 7:55 am
Location: North East OH, ICOA 3904

Re: Splitting Crankcases

Post by EMS »

pouchy750 wrote: What sealant would you recommend?
4 out of 5 dentists would probably recommend Yamabond or Hondabond. Essentially the same stuff. I am the odd man out and recommend Hylomar.

http://hylomar.com/

daves79x
ICOA Technical Director
ICOA Technical Director
Posts: 4738
Joined: Sun Oct 01, 2006 8:05 am
Location: Knox, PA
Location: Knox, PA

Re: Splitting Crankcases

Post by daves79x »

Lets say this - the same sealant you should have used on the crankcase halves. I use Hondabond since it's the original gray color. I believe I mentioned that in your first thread about the missing seal.

Dave

User avatar
NobleHops
ICOA Member
ICOA Member
Posts: 3867
Joined: Mon Jan 25, 2010 7:17 am
Location: Tucson, Arizona, USA
Location: Tucson, Arizona, USA

Re: Splitting Crankcases

Post by NobleHops »

daves79x wrote:Lets say this - the same sealant you should have used on the crankcase halves. I use Hondabond since it's the original gray color. I believe I mentioned that in your first thread about the missing seal.

Dave
At the risk of being obtuse, is the wisdom here that one should use sealant on engine oil seals when installing?

N.
Nils Menten
Tucson, Arizona, USA '80 CBX, sort-of restored :-)

daves79x
ICOA Technical Director
ICOA Technical Director
Posts: 4738
Joined: Sun Oct 01, 2006 8:05 am
Location: Knox, PA
Location: Knox, PA

Re: Splitting Crankcases

Post by daves79x »

Nils: Not as a rule, I'd say, but that particular one is basically sealing that part of the crankcase joint. And all the engines I've split seem to have sealant in that area. As with anywhere, just don't go overboard.

Dave

Post Reply

Return to “ENGINES: Maintenance, Performance, Parts Sources”