Topic: Chain ruined motorhousing/cover

[jensk]

I have this old CB550k3 '77 that i am working on restoring. I had to change the front sprocket so i removed the left cover. Then i discovered that the Po once had an chain accident that had ruinet the housing of the motor. So now the is an opening from the front sprocket to where the oil punp is. I could get a new cover but i will have to dismantle the engine to replace the housing. There arent any holes into the gearboks - just to the compartment where the oilpump is - like this

Can i ride the bike as is or do i need to repair/renew the broken housing

As i had the cover off i rinset the remains of old chainlube of everything in there. Then i noticed that the chain had chewed on the plastic part right in front of the sprocket:

It doesn't look like there is comming oil out of it. Do i need to change the plastic part - what ever it is?

[bryanj]

should be ok to use BUT i would get a new plug whilst you can. www.westernhillshonda.net did have some in stock a while back. You have to split the crankcase to change it

[TwoTired]

This damage looks typical of what an o ring chain will do to a cb550.  It's too wide.

If the seal or case is not leaking oil, it should be okay.  Inspect for cracks, though.
 Clean the area well, let dry, and spray a light coat of K2R onto the area.  Let dry and wait several hours.  The powder will wick oil out of any cracks, showing their location.  I've heard spray foot powder works, too.

 I did not replace the seal on mine as the scarring was not that severe.  I did put some of that black plasti-dip stuff over the scar on the seal.  And, I have found RTV in that location on other CB550s.  I'm not certain either is necessary.

Cheers,

[jensk]

Cleaned it up 2 weeks ago and it seems here is no oil leaking - it stays dry. But then again the enigne have been standing still all the time as I am trying to restore carbs etc. Would it sweat oil even if the engine is not used or do I need to run the engine to se if the seal is oil tight.

I think it is more than 10 ago the o-ring chain made the marks on the seal. The bike had been standing stil for many years after PO had a minor accident. The very rusty chain I took of was very worn - stretched a lot - and it wasn't an o-ring chain. I guess that it is more than 10 years ago the marks where made by the o-ring chain.

[TwoTired]

Would it sweat oil even if the engine is not used or do I need to run the engine to se if the seal is oil tight.

A crack would be a small reservoir for oil and it would stay in by capillary action while cold.  The powder would wick it out.  Heat could make it weep, too.

It's probably okay.  What have you got to lose by running it for a while?  Oil drips?  If you don't want to try the powder thing now, you'll find out later if it starts marking its spot.

Cheers,

[supersport_CB400F]

If that plug is made the same way as the 400 plug then its rubber covering a metal core and should not give you a problem unless you can see the metal.

[jensk]

I will wait and see. I have got the carbs on yesterday evening. I hope to have a first go at starting her (first time in 10 years or maybe more) this week. I will have a good look at the plug to se if any oil is running out.

As believe that it is the bare metal of the plug i can se i the groove that the chain has made.
/jk

[Bodi]

Take a look at the sprocket. In the pics I can see a raised area where the holding part bolts on, if the opposite side of the sprocket is flat I would mount it with the flat out. That will space the chain a bit outward. I'm not sure about 500/550 sprockets but I've seen other Honda sprockets that can be mounted backwards and cause chain wear and alignment trouble.
As far as the plug goes, if it doesn't leak then don't worry. I would get a new plug (and a set of oil rings) now in preparation for a future expedition into the main case though, these parts are now fairly easy to find but they'll only get rarer. Even if the metal is showing it may not leak, and the metal isn't going to rust there - it'ss be totally covered with chain lube guck in no time.
The broken out bit into the oil pump cavity isn't a problem except the pump will sure get dirtier than normal. If you clean it up really well (using acetone and/or brake cleaner) you could build a new wall up with JB weld, or attach a sheet aluminum patch with it. Not really necessary but a nice touch.