WTF evaporating oil ?

[carlos fandango]

I rebuilt my engine a couple of months ago, just new bearings and seals.
Almost immediately it kept jumping out of 2nd gear, which was odd because it didnt do it before, anyway i tightened the cables and this cured it, with it only doing it when really accelerating hard. So today i thought id get the side of and check the Gearbox and selector. when i drained the oil there was only about 150ml
Now i know i filled the gear box up with a 500 ml of rock st90 and toped it up from a second bottle?
No noticeable oil leak ?
And no smelly black smoke ?
Any ideas ?? ive only done less than 300 miles since the rebuild ?
Looks like the crank will have to come out and change the drive side bearing and oil seal again
The clutch bush is worn quite a bit so ill probably have to change all the rest of the bearings as well

[Toddy]

I rebuilt my engine a couple of months ago, just new bearings and seals.
Almost immediately it kept jumping out of 2nd gear, which was odd because it didnt do it before, anyway i tightened the cables and this cured it, with it only doing it when really accelerating hard. So today i thought id get the side of and check the Gearbox and selector. when i drained the oil there was only about 150ml
Now i know i filled the gear box up with a 500 ml of rock st90 and toped it up from a second bottle?
No noticeable oil leak ?
And no smelly black smoke ?
Any ideas ?? ive only done less than 300 miles since the rebuild ?
Looks like the crank will have to come out and change the drive side bearing and oil seal again
The clutch bush is worn quite a bit so ill probably have to change all the rest of the bearings as well

Daft question Russ are both Level and Drain plugs tight ? Have you taken the Hub off ? any oil in there??

If Not Eden will have syphoned it off while you were asleep

[carlos fandango]

Lol it stands a chance
The hub and drain plugs are ok ?

[Supereibar]

Russ, that happened to me with a Chubby Checker crank.. erm.. a MECeur race crank that I had on a GP200 engine. When using it, I wouldn't smell a thing, nothing, but the engine would still drink up the casing oil right away. I would nottice that I had no oil at about 500kms so yes, more or less the same distance as you. Oddly enough mine used to jump out of 1st gear going uphill with a lady riding pillion :biggrin:

[Toddy]

Lol it stands a chance
The hub and drain plugs are ok ?

One of our lads had a dodgy casing side plug which didnt seat correctly and lost oil , rear hub was wondering if seal had gone or Bearing spinning in casing mate

[dave wheeler]

my gp would stand all winter without so much as a drop on the floor but a 250 mile thrash was enough to loose half the chaincase capacity, ive now fitted a 1mm thick chaincase gasket as it seemed that the chaincase seal was fine when cold but a combination of thinner (hot) oil and heat expanding the gap in the chaincase was enough to loose oil

[carlos fandango]

We'll got the crank out and the oil seal looks fine it, was a double lip one, I've changed it anyway.
So I'm still scratching my head ?
There are only three reasons for the lack of oil that I can think of ...
1. Operator error, i.e. not putting it in in the first place. I'm Deffo I did , as the empty oil bottle is still I'm my bench, and as id just rebuilt it there would be no oil in what so ever.
2.leaking externally from a gasket , oil seal or crack... No signed of an oil leak ?
3 leaking internally. Drive side oil seal, or possibly rear hub. . Again no signs of oil any where or oil seal damage , the only thing I've found is a bit shaved of the layshaft O ring but no signs of oil around the brake area ?
Oh well , I'll put it back together. It's just another thing to worth about ! Lol

[Toddy]

My moneys still on Eden takin it

[cezeta]

there is a fourth, twisted crank will let the oil through a good seal

[carlos fandango]

there is a fourth, twisted crank will let the oil through a good seal

Hmmm I hadn't thought of that.
I did check the crank after I rebuilt it, but the bodgers method with a screwdriver in the end of the crank, and all seemed fine