CB77 305 Sprung a Leak

[akpasta]

Pulled the k/s cover off today and about a double-shot glass worth of oil spilled out of it, did not look good. The oil seemed to be coming from the area in this picture.



The area further back there was a bit oily and sludgy in the 200 or so miles since I last had the cover off, but not wet the way this area was, so I imagine the leak is coming down to somewhere around the circled area. What is behind the stator that could leak? Is it a crank seal leak? I put the exhaust back on and carefully idled the bike to see if I could observe, but I saw no leakage. Is this a hard seal to replace?

Is there much harm in running the bike just around town for now as long as I keep an eye on the levels and the leak doesn't turn into something major?

How could this happen on a bike with 1500 miles on the rebuild? Should I be looking elsewhere for the cause of the problem besides just a faulty seal? What should I look for when ordering a replacement of whatever I need? Are some good some bad? Diff types for diff serial number series'?

thanks.

[rzgkane]

Crank seal or starter sprocket seal. Same as mine. Be prepared to replace them both. I submitted a writeup of this process not too long ago.

http://www.honda305.com/forums/post52860.html#52860

Not impossible to damage one or the other upon reassembly even if they were new.

Pulled the k/s cover off today and about a double-shot glass worth of oil spilled out of it, did not look good. The oil seemed to be coming from the area in this picture.



The area further back there was a bit oily and sludgy in the 200 or so miles since I last had the cover off, but not wet the way this area was, so I imagine the leak is coming down to somewhere around the circled area. What is behind the stator that could leak? Is it a crank seal leak? I put the exhaust back on and carefully idled the bike to see if I could observe, but I saw no leakage. Is this a hard seal to replace?

Is there much harm in running the bike just around town for now as long as I keep an eye on the levels and the leak doesn't turn into something major?

How could this happen on a bike with 1500 miles on the rebuild? Should I be looking elsewhere for the cause of the problem besides just a faulty seal? What should I look for when ordering a replacement of whatever I need? Are some good some bad? Diff types for diff serial number series'?

thanks.

[akpasta]

Hm, removing the stator. Looks simple but I'm sure deceptively so, or maybe not?

Is the picture you show with both seals removed? Does the crank seal fit into that metal area around the crank arm? Would it be worth finally tracking down a manual before tearing into this?

I've never removed a stator from a motorcycle, only mopeds (ha). I imagine taking it off is gonna mess up the timing, or does it fit back on the crank in such a way that it stays the same?

So you need a rotor-pulling tool, eh?

[rzgkane]

Removing the stator from the point you are already at requires only the removal of the three bolts at its perimeter that hold it to the case. Just be careful when removing the bolts so as to not let the stator slam around against the rotor or engine case.

The crank seal is a large seal that goes right in that big hole you see im my pic. It actually seals the crankcase to a surface of the starter clutch sprocket. The shaft of the crank is actually sealed by the small seal inside the starter clutch sprocket (this is the one that did the majority of the leaking in my bike becuase it was crusty old). It can get damaged when sliding over the crankshaft so I put a few loops of electrical tape on the crank as I slid it on.

Not a difficult job. But be sure to remove with an exacto knife some of the sharp metal of the crankcase or you will destroy the crank seal when popping it in. If Davo put that seal in I'm sure he already did this. I think he was the one who recommended it to me.

I also recommend you get some 3M weatherstrip adhesive and put a small ring of it around the exterior of the crank seal 1. to lubricate the installation of the seal and 2. to hold it in there tight.

As for the rotor puller, I guess you can use a hardened 17mm bolt in place of the tool. I didn't do it that way but I have no reason to doubt Hillhudson who said you could.

And nothing in this process affects the timing in any way.

Hm, removing the stator. Looks simple but I'm sure deceptively so, or maybe not?

Is the picture you show with both seals removed? Does the crank seal fit into that metal area around the crank arm? Would it be worth finally tracking down a manual before tearing into this?

I've never removed a stator from a motorcycle, only mopeds (ha). I imagine taking it off is gonna mess up the timing, or does it fit back on the crank in such a way that it stays the same?

So you need a rotor-pulling tool, eh?

[akpasta]

Thanks for the reply. Ok. Not sure how to use a bolt to pop the stator off. I see here- http://www.honda305.com/forums/rotor-re ... r%20puller

16x60 SAE bolt, screw it in to a spot I haven't seen yet, but I'm sure is obvious enough once I pull things apart. I don't have an impact driver, so use a wrench and hit the wrench with a rubber mallet to "impact" the thing and pull it off?

As far as the seal goes. Will this NOS set do the trick? Are all the seals people use NOS? Perhaps that's why some of them fail no matter how well they are installed, 40-year old rubber, you know?

[rzgkane]

I did not use a factory starter sprocket seal. I used one I bought from an oil seal outfit in irvine, ca. I did use the crank seal from one of the ebay kits.

Thanks for the reply. Ok. Not sure how to use a bolt to pop the stator off. I see here- http://www.honda305.com/forums/rotor-re ... r%20puller

16x60 SAE bolt, screw it in to a spot I haven't seen yet, but I'm sure is obvious enough once I pull things apart. I don't have an impact driver, so use a wrench and hit the wrench with a rubber mallet to "impact" the thing and pull it off?

As far as the seal goes. Will this NOS set do the trick? Are all the seals people use NOS? Perhaps that's why some of them fail no matter how well they are installed, 40-year old rubber, you know?

[Hoosier Tom]

Those seals from RetroBikes are not NOS. They are brand new made in Taiwan. I have spoken with Terry personally about this and he also tells me they are working on getting CB77/CB72 speedo rubber gaskets reproduced.

HT