Topic: 350F: countershaft seal requires splitting cases?

[ADW]

I sure hope not. I've developed the tiniest little niggling leak that is coming from the countershaft seal on my 72 CB350F. Should be no big deal to take off the sprocket and put in a new one from the outside, right? Maybe not...

The parts diagram shows a bit of a "nub" on the outer diameter of the seal, and it sure looks like it's supposed to fit in a mating drilling in the case half.

Then when I look at the Service Manual in the Countershaft section, on page 27 it says "Install the oil seal with its dowel fitted into the pin hole in the upper crankcase".

Can any of you 350F owners or those otherwise-knowledgeable on this confirm or deny the ability to change out the countershaft seal on a 350F withOUT splitting the cases? (Looks like the shifter seal can be done without splitting, that also may be where the leak is). Thanks.

[IBleedHondaRed]

i have this same issue on one of mine. anyone?

[iron_worker]

I know on the 750s there is no "nub" and it can be pressed in with the cases together. However the crank seal behind the points does have a shoulder on it and needs to be put in place whilst the cases are apart ... which I figured out the hard way when I forgot to install it the first time I put my cases together. While researching if I did truly need to split my cases again I talked to Ken at Cycle X who said that he had heard of people cutting the shoulder off, pressing the seal in, and "staking" it in by raising some dimples around it with a hammer and punch. He said, though, that he has never done it himself but heard it does work in a pinch.

As for your specific seal ... I can't say for sure.

Hope this helps a bit.

IW

[IBleedHondaRed]

the diagram in the manual shows installation with the cases split :/

[lucky]

I sure hope not. I've developed the tiniest little niggling leak that is coming from the countershaft seal on my 72 CB350F. Should be no big deal to take off the sprocket and put in a new one from the outside, right? Maybe not...

The parts diagram shows a bit of a "nub" on the outer diameter of the seal, and it sure looks like it's supposed to fit in a mating drilling in the case half.

Then when I look at the Service Manual in the Countershaft section, on page 27 it says "Install the oil seal with its dowel fitted into the pin hole in the upper crankcase".

Can any of you 350F owners or those otherwise-knowledgeable on this confirm or deny the ability to change out the countershaft seal on a 350F withOUT splitting the cases? (Looks like the shifter seal can be done without splitting, that also may be where the leak is). Thanks.

If it has a dowel pin to keep it from spinning, you will have to split the cases.

[ttr400]

Also a very important thing to note is the nub is to locate the seal in the correct position. As if you look at the seal there is a small oil hole that is fed oil direct from the small secondary oil pump, this small hole must align with the feed hole in the casing.
The small secondary oil pump feeds the counter shaft, main shaft and clutch etc.

I prefer to use an OEM seal. if using an aftermarket seal always check that this hole is not blocked.

So yes split the casing to replace.

Kevin

[ADW]

Kevin, it's not the answer I wanted to hear, but is the information I needed to know! Thanks.

[IBleedHondaRed]

I VERIFIED ALL OF THIS ON A CASE I ALREADY HAVE SPLIT AND EXAMINING THE SEAL THAT CAME OUT

[ADW]

I VERIFIED ALL OF THIS ON A CASE I ALREADY HAVE SPLIT AND EXAMINING THE SEAL THAT CAME OUT

Thanks for the verification!