Oil disappearing from sight glass

[declan]

As posts says I'll fill my engine up and after maybe a minute or 2 of running the oil will disappear off the sight glass and I'll have to put another 200ml give or take to get it back on the glass it had a bad right hand crank seal but that's all replaced now it's no longer burning gearbox oil I have no oil in the radiator any ideas I know it can't be vanishing but im not too sure

[Calum]

@declan I mean, I don't know what to say. 200ml is a lot to lose in a couple of minutes. Are you sure that the glass isn't just not clear. I never use the sight glass. Just 750ml and forget about it.

[DTR+NSR]

May have miss understood, but are you checking the oil level with the engine running?

[declan]

I measured my oil yesterday and I only got around 200ml out of my engine even though I filled it up to the sight glass then topped that up twice I've checked my crank seals no issues there my Water pump seal was pretty much gone but no oil in the rad I'm gonna try measuring my 750ml out and go from there when I install my pump seal if it disappears again the only thing left is the case halves aren't sealing and gearbox oil is leaking into the crank case but with the amount of oil missing you would think it would be a smoke show and spewing gunk out of every orafice but it doesent ,I'll keep you posted seal comes in Monday I think

[declan]

@dtr-nsr no filled on a cold engine and left for a few days and the oil doesent return, I'm hoping that for whatever reason the oil is getting trapped in the clutch cover so it looks on the sight glass that my oil is full but when it runs the oil is going through to the rest of the engine this doesent make much sense though since the oil passage ways all look clear

[SpookDog]

@declan
Filled from cold and left 2 days, without running? If so it’s impossible for it to have gone into the crank. It would of hydro-locked the crank, and/or been impossible to start...
Also are you saying you got only 200mls when you drained the oil?...

[Calum]

@spookdog It wouldn't hydrolock, but I know what you're saying.

Obviously on four strokes, the valves close and the fluid has nowhere to go. On a smoker it would come straight out the exhaust and make a right mess!

[declan]

@calum I think i have sorted the "issue" I haven't ran the bike but I'm pretty confident I wasn't putting enough oil in I measured the new oil 750ml and about half way filling the engine the sight glass started to fill so before I would have stopped this time I didn't and kept going I'm assuming you are supposed to fill the engine with the measured amount run the engine then check the level on the sight glass and top up if necessary I've never ran into this on my dtr but I've always measured the oil for that
engine

[declan]

@spookdog and no I were running the engine

[SpookDog]

@declan
You don’t even need to top up, the gear oil doesn’t get used up like a four stroke engine does. It has nowhere to go unless it’s leaking.
Just ‘fire & forget‘ 750ml into it ...

[declan]

@spookdog I know but depending on how much oil there is or isn't in the bottom end you may need to the manual calls for 800ml if you have rebuilt the engine so it depends what work you have done or how long it's sat without oil

[Calum]

@declan what

No just drain the engine oil. 750ml and then don't worry about it.

Can't say I have ever had a problem.

[declan]

@calum that's what Haynes says but anyways it should be good to go now

[SpookDog]

@declan

I know, but the sight glass is problematic. I’ve seen posts where people thought the oil had disappeared but really had gone above the glass

If my gear change feels smooth, I’ve got oil