cb350 leaking gas/oil?

[ronmexico]

Hey Guys,

So, 1st post here...

I have a 71 Honda CB350 with 12,000 miles that I've been running most of the summer without doing much more to it than an oil change, new battery, and spark plugs. The bike runs pretty strong, but I noticed what appears to be a gas/oil leak coming from the where the breaker assembly is located on the bike. From the pic you I think you can see the moisture from right above the spark plug cable. Head gasket? Any ideas? Any help is much appreciated.

 

[Flugtechnik]

Does it smell like oil or gas?

There is an oil seal that goes around the spinning eccentric shaft behind the advance mechanism which is behind the points. It is probably worn and needs to be replaced. I don't know if you have to take the points housing off to get it out because I don't have a 350. Anybody know?

 

[crazypj]

That's usually a bad thing.
Usually it means lubrication break down to cam bearings.

To change seal.
First remove points plate, then, you have to take advance mechanism off cam end, its only one 6mm bolt (10mm head)
It should slide straight off. don't pull cam off advance mech though, only fits properly one way.
dig out old seal.
De-burr hole, slide new seal into position.

PJ

 

[DrJ]

I've changed this seal. Yes, you can do it without disassembling the top end. The points housing will slide out only if the left piston is at TDC and both valves are closed, you can tell by wiggling them through the tappet covers. If they are slightly loose, both valves are closed and piston is at TDC. But you'll need to recheck valve clearance and points timing after reassembly.

 

[Wee Todd]

as stated pull the points and auto advance,,drill or punch a small hole in the seal with a scriber and thread in a ,,,,,,,,,,wood screw tear it out with dads 30 yr old vise grips,,match the outer diameter of the seal to a DEEP socket...lube the cavity, gently tap in the new seal in place, if it tears on the outside of the seal,have a second seal handy,,,it shouldn't, it's being driven into a blind hole in the casting unlike seals affixed in split cases (tighter tolerances),,,honda seal is directional(spec) generic seals work fine,,,but some do weep oil,,,,,,,,,good ruck

 

[Stella CB350]

Im having the same problem with my 72 CB350. Oil is everywhere but the bikes run fine until about a week ago, now it sputters at idle and when gas is cranked it dies completely. I have called around about the seal and have been told the part is discontinued and unavailable, and that I will need to make a replacement. Can anyone tell me what this seal/gasket is called and possibly post a link to where it can be purchased. Thanks alot for all of your posts, i dont know that I can fix it with my experience, but its nice to know what the dang problem is.
Dylan K
Eureka, Ca