Oil leaks

[BrianDowning]

Hi All

My largest oil leak appears to come from the area around where the gearbox and chain cover meet. I can't see anything between, as the area is too tight. Any suggestions as to what might be the most likely cause? I'm thinking of removing the chain cover to inspect, as the leaking oil seems much dirtier than the gearbox oil. Both the gearbox and engine sump lose oil, but the sump loses oil more rapidly. The leaking oil is dirty, seemingly as dirty as the sump oil.

Cheers, Brian

[ChrisTheChippy]

Hi there is a seal right at the back of the gearbox. It requires removing the gearbox to get at it. Mine (g2) was leaking from there. The seal is avaliable from Villiers spares at least that's where I got mine from. I'm not absolutely sure but I don't think the club stock this seal . Sorry I can't help with a part number it was a few years ago. I think that may be your problem at least it stopped the leak in that location on mine now it leaks from around the gear lever (sigh ). There are a few remedies for that but at the moment I'm too busy to try them.

[BrianDowning]

Thanks Chris

Is the seal at the back of the chain cover or is it part of the gearbox?

Brian

[g80csp11]

is it this oil seal ?
https://www.amoc-parts.com/store/comersus_listItems.asp
Main bearing oil seal -lightweights
http://archives.jampot.dk/book/Spares_l ... s_List.pdf

Im only guessing as I don't have a lightweight , but its listed under gearbox section , and if so in stock in spares department

[SPRIDDLER]

The leaking oil is dirty, seemingly as dirty as the sump oil.

I know little about L/W models but if the oil is as dirty as that I wouldn't expect it to be coming from the gearbox.

[Les Howard]

Is there a breather hole/pipe located in that region that is blowing out old engine oil? Although I have owned the light-weight model I cannot remember that detail

[BrianDowning]

I do suspect that the problem is either the seal at the back of the chain case or a breather pipe, or both! I don't suspect the gearbox, as it was professionally overhauled and the 0il is clean. I guess the only way to know is take it apart.

Brian

[Red Gauntlet]

If you have EP80 in the gearbox, ATF in the chain case and engine oil in the engine, it is fairly easy to determine what is falling out of where by the colour or smell, having said that it may be possibly either overfilled in the chain case (that felt seal is not very oil tight) or it is breathing heavily, i.e. worn bore and or rings, if the gearbox is rebuilt properly.

[BrianDowning]

I think it's all 50w but that's an interesting idea. Where exactly is the felt seal you're referring to?

[Red Gauntlet]

The one in the rear of the chain case, it is sandwiched between the round metal shield halves, the gearbox primary shaft runs through it behind the clutch. (910101 FLOATING SEAL KIT HEAVYWEIGHT ALLOY PRIMARY CHAIN CASE-- SPOT WELD OR POP RIVET INTO POSITION)