Now where is this oil leak coming from?

Johnnymac · Nov 24, 2011

Happy Thanksgiving everyone. pulled my Amals and cleaned them up last night and replaced the gaskets. Took her for a Thanksgiving spin around the block this afternoon. She was running much better than before but when I got home, I had a lot of oil dripping from under the motor. I got down on my hands an knees and it looks like there is some sort of leak coming from where the chain sprocket is. The guy I bought my bike from said that there were no leaks other than the chain oiler. Well, looks like at some point the chain oiler was plugged up. Can someone advise where this leak could be coming from? My chain is completely soaked. I guess this is why i thought that my primary cover was leaking.... certainly not coming from there. Thanks!

Hobot · Nov 24, 2011

If one over fills to manual spec level the gear box will puke out lube till it seeks its natural level, so supsect that. If the main shaft sleeve bushs worn/busted up then theres a free path right onto the sprocket. If primary over filled to manual spec or level plug then it will puke oil out until it reaches its natural innate level just touching bottom of links at bottom of chain run. If primary chain too tight it might be straining the main shaft to open oil gap even more permantely now. This assumes chain oil is blocked and not oil coming forward of sproket being blown back.

pete.v · Nov 24, 2011

Take out the level plug on the primary and see how much oil comes out. May need a crank seal and a reed valve on the breather. The felt washer may also be toast but that is the effect of the cause.

Smell it to see if it is motor or gear oil.

JimC · Nov 24, 2011

If you don't have a PCV valve in the breather line it WILL leak oil, somewhere.Them old Norton case don't like pressure.

Johnnymac · Nov 24, 2011

JimC said:
If you don't have a PCV valve in the breather line it WILL leak oil, somewhere.Them old Norton case don't like pressure.

I think i will try the pcv valve first... Anyone have any pic of the valve installation on an MKII?

Matt Spencer · Nov 24, 2011

Thats NOT an Oil Leak . ! Its Just a Drip . Carefull , or youll have it rusting !

:shock: :roll: :wink:

DogT · Nov 24, 2011

I don't have a pcv in my stock 69 and I only get a drip out of the very bottom of the engine once in a while. I'm sure it's the crank flange leaking when it wet sumps. Doesn't leak at all on the road. But the pcv is a good idea, but that's a pretty healthy leak. If it were mine I'd have the primary apart and check out the bushings on the GB mainshaft and the felt seal in the inner cover. Not a quick job, but hey, it's getting on to winter.

Dave
69S

Torontonian · Nov 24, 2011

Obviously should never have pulled the Amals...

Sweenz · Nov 24, 2011

I have seen oil leak out the end cap of the swingarm spindle on the primary side & run over the back of the chain case..
Just another potential cause.

Sweenz

Matt Spencer · Nov 24, 2011

Probly been sitting on the prop stand . Better to be on the level .

AussieCombat · Nov 24, 2011

G'day Johnny,
Unfortunately we can all guess as to where the oil is coming from, but it's a guess.
Clean it all up as best you can, try to eliminate different things.
Are you certain the breather/overflow to the chain is not dripping. Try placing a plastic bottle over the end.
Take the chain off and run the engine in gear for a short time, this might show a main shaft seal leaking.
Have another look.
Primary cover, clutch, running gear and inner case removal is not a difficult job, wip it off and have a look inside.
Then you will be sure. It could be a crank shaft seal. Who knows.
AC.

drones76 · Nov 24, 2011

As AC said, clean it up real good. The next thing you can do is spray some powdered foot deodorant around the areas that you suspect. Or just sprinkle it with talcum powder. Take it for a ride and see where the wet spots are.

Hobot · Nov 24, 2011

Don't bother with the power if ya can't just blast clean first then ride a 100 yd or so at a time then peek around, rather annoying obnoxiously closely. Meanest leak trick on me was the fork seal blowing back on head then down and back from there.
Most dangerous leak was the front mastercylinder leaking blowing away until no brake one good squeeze to the next nothing at all.

Guido · Nov 25, 2011

Johnnymac said:
JimC said:

If you don't have a PCV valve in the breather line it WILL leak oil, somewhere.Them old Norton case don't like pressure.

Click to expand...

I think i will try the pcv valve first... Anyone have any pic of the valve installation on an MKII?

Johnnymac · Nov 25, 2011

Thanks guys. It is probably best if take it apart and see where it is coming from... So I went by my localshop today and got a complete commando gasket kit including various seals - including the ridiculous felt ring seal. I also picked up the clutch compression tool to pull the clutch off the bike. I thought that i had everything i needed to pull off the chain case but in looking closer at the shop manual, looks like I still dont have the sprocket puller (060941) and the clutch tool (061015) Is there a work around or do i need to go back up the the shop to get these as well?

Hobot · Nov 25, 2011

A stout steering wheel puller, ie: slotted bar for two bolts with big center bolt and a torch first will pull the crank sprocket off. When I went into my first Combat, only, because, it was leaking, not smoking, I found enough wrong it took me 5 yrs to recover and I ended up a changed being inside and out. Best wishes it all goes like the manual says, except where its wrong of course.

drones76 · Nov 25, 2011

Johnnymac said:
Thanks guys. It is probably best if take it apart and see where it is coming from... So I went by my localshop today and got a complete commando gasket kit including various seals - including the ridiculous felt ring seal. I also picked up the clutch compression tool to pull the clutch off the bike. I thought that i had everything i needed to pull off the chain case but in looking closer at the shop manual, looks like I still dont have the sprocket puller (060941) and the clutch tool (061015) Is there a work around or do i need to go back up the the shop to get these as well?

I was able to work around the clutch tool by having someone hold the back wheel while turning the alternator nut.

A cheap $10 puller from the local autoparts will do for the sprocket puller. A thread with picture is here:

post129687.html?hilit=sprocket%20puller#p129687

JimC · Nov 26, 2011

I think i will try the pcv valve first... Anyone have any pic of the valve installation on an MKII?

DogT · Nov 26, 2011

You can make a proper clutch tool with a large pvc end cap and the proper bolt/nut. For the rotor, you really need a puller, they can stick like crazy, give it pressure, taps on the end of the puller bolt, heat and sauce all help. The Norton tool is not the only one that will work. You should have these items anyhow.

Dave
69S

Norton-Villier · Nov 26, 2011

johnnymac, When you put it back together smear some RTV silicone around the stater wire exit hole. I had some leaks from there leading me to believe thay were coming from somewere else.

Phil

Now where is this oil leak coming from?

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