Topic: Oil Leak in Points Housing

[aaguilar3]

Hello,

I have a 73' CB 350F and I had been noticing a few drops of oil leaking from the points cover on the right side after a ride. I opened it up yesterday since I was planning to do the tappet adjustment. I found in the center bottom there's a small puddle of oil. From what I've researched so far it could be a bad oil seal that's part of the connecting rod in the crankcase. Any thoughts? I will probably look more into it this weekend but just wanted to start the thought process of what my be involved. Any help would be appreciated.

[flybox1]

Yes.  there is a crank seal there....  It has a lip on it and is best replaced by splitting the cases, however, you can remove the points plate and advance unit, clean it really well, wipe it down with acetone, and then give the seam a few thin coats of permatex black non hardening sealant.
That'll hold it for quite some time until you NEED to pull the engine.

Just be sure to mark your points plate on at least 2 posts, so it can be easily relocated without major fussing with the ignition

Oil Seal, 30x42x8 Cb350f Four 1972 Usa
fits:
Honda
product number:
91201300003
CMS product number:
HO0134.0821

[Deltarider]

It's not unusual to see some oil there, the more if bike sat a long time. It's no big thing. I have good results running Castrol High Mileage 15W-40. Some blends make those rubbers swell just a little bit more. Riding the bike more also helps.

[aaguilar3]

So you're saying for the seam to go ahead and clean up and follow up with permatex? Also, order the oil seal and replace that too right? Is that pretty straight forward? I appreciate all your help.

Yes.  there is a crank seal there....  It has a lip on it and is best replaced by splitting the cases, however, you can remove the points plate and advance unit, clean it really well, wipe it down with acetone, and then give the seam a few thin coats of permatex black non hardening sealant.
That'll hold it for quite some time until you NEED to pull the engine.

Just be sure to mark your points plate on at least 2 posts, so it can be easily relocated without major fussing with the ignition

Oil Seal, 30x42x8 Cb350f Four 1972 Usa
fits:
Honda
product number:
91201300003
CMS product number:
HO0134.0821

[aaguilar3]

Thanks for the input. It's very much appreciated.

It's not unusual to see some oil there, the more if bike sat a long time. It's no big thing. I have good results running Castrol High Mileage 15W-40. Some blends make those rubbers swell just a little bit more. Riding the bike more also helps.

[aaguilar3]

Or do you mean  part# 91201300003 is the one you need to split the cases for?

So you're saying for the seam to go ahead and clean up and follow up with permatex? Also, order the oil seal and replace that too right? Is that pretty straight forward? I appreciate all your help.

Yes.  there is a crank seal there....  It has a lip on it and is best replaced by splitting the cases, however, you can remove the points plate and advance unit, clean it really well, wipe it down with acetone, and then give the seam a few thin coats of permatex black non hardening sealant.
That'll hold it for quite some time until you NEED to pull the engine.

Just be sure to mark your points plate on at least 2 posts, so it can be easily relocated without major fussing with the ignition

Oil Seal, 30x42x8 Cb350f Four 1972 Usa
fits:
Honda
product number:
91201300003
CMS product number:
HO0134.0821

[flybox1]

correct....

I included the seal part number just for reference, in the event you choose to pull the engine out of the bike, and split the cases.
The seal has a small lip on it, which fits in a groove in the case. 

Clean and seal it up for now.  See how it does.  The oil in there really wont hurt anything.  If you continue to ride without fixing it, just check and top off your oil once in a while, and wipe out the oil from the inside of the points area.

[aaguilar3]

Got it! That makes sense now. You've been helpful. Yeah it's not much that it leaks.

correct....

I included the seal part number just for reference, in the event you choose to pull the engine out of the bike, and split the cases.
The seal has a small lip on it, which fits in a groove in the case. 

Clean and seal it up for now.  See how it does.  The oil in there really wont hurt anything.  If you continue to ride without fixing it, just check and top off your oil once in a while, and wipe out the oil from the inside of the points area.