Signs of a rear main seal needs replacing

[Vespa no more]

Can experienced eyes confirm that I should be ordering a replacement rear main seal before the clutch is pulled.


And if this is leaking, I assume I should be replacing the front seal as well.


Thanks

Guy

[Motorhobo]

For what it's worth, and I might be wrong, but when my buddy did my RMS back in 2008 I seem to remember him mentioning that you could tell from the sling pattern whether the oil in the bell housing is from the RMS or another source. I seem to remember (that's my standard disclaimer since it was a long time ago and my memory sucks) that the slung oil was concentrated in the area in front of the clutch assembly closer to the sear itself, because that's the source of the leak and most of it is slung before it can travel past the clutch housing.

Did you smell it and confirm that it's engine oil and not gear oil? If it's gear oil, then you have a bad clutch pushrod seal which is a helluva lot easier to deal with than the RMS.

[Scott_]

If the clutch hasn't been pulled before, I'd bet that at a minimum the clutch nut o-ring is bad(purely from age), and not necessarily the rms.
Either way you have to split the clutch pack(MAKE SURE YOU MARK ALIGNMENT OF THE 3 FIXED PARTS, not including the friction disk) to get to the o-ring.

[Snowman]

When I did my clutch I did the main seal, it wasn't leaking. I just thought that I am this far in anyway I may as well. The way my luck goes it would have started leaking 100 miles down the road if I hadn't.

[Martin]

Replace the seal and the "O" ring otherwise if it leaks you will be kicking yourself. Replacing the seal and "O" ring is well documented. Apparently you can now get the "O" ring in the correct size ( make sure you get the correct size) in Viton which is a lot better and cheaper. The seal is also available non OEM. As stated mark all clutch components an reassemble with the marks lined up . You will also need a driver to replace the seal check that you have the correct depth. Various home made solutions for driver have been used. A large 1/2" drive tension wrench is also needed and a method to hold it while you tension it.
Regards Martin.

[Vespa no more]

Thanks everybody
The gear actuator / selector rod rear seal is dead (think I killed it). But given the age of the bike, the rubbers are either at or near the end of their life(s).
Will mark up all parts before removal
Motobins order being organised.


In the mean time, I'll continue cleaning the outside of the motor before I open it.
Am happy with petrol / gasoline, fine gauge steel wool and compressed air.


Will call the local abrasives place and get a quote on bead blasting.
Any thoughts / experiences on this front?


I don't really want to strip the whole bike and repaint - yet.


Regards


Guy

[technostructural]

When I opened up my bell housing, I noted almost the exact same looking residue.


I did a bit of an investigation and reasoned that it was caused by excess spline lube.


Not sure if this helps.

[Vespa no more]

In my last post here, I stated I was happy with the petrol / gasoline and manual cleaning.


Spoke to the local abrasives dude and after talking himself up for five minutes, told me not to use the petrol... as it affects the outside surface of aloominum. Long story short, he said use what the truckies use if going down this path.


Will find out what is recommended.


I don't want it spotless - rather original. Oh and I am a tightwad.


Guy