Dodgy casings

[wack 63]

Just stripped a mates Rapido down and noticed gear oil around the crank and piston skirt and although the scoot hasn't been smoking badly and gear oil ok there was definately some in the crank case. The seal grips the crank and is less than 1000 mls old,the MB drive plate was tight and the Halite washer was crushed all around as it should be.I read in the new Sticky book that some casings are faulty and will cause the seal to leak after a few miles but does not name the fault.I have looked closely at the casing and can't see anything obvious apart from the screw holes are a tad out when the drive plate is sat in the casing but the screws all go in easy and sit well.Any ideas?

[RICSPEED]

the screw holes are the fault

[wack 63]

So what are my options ? drill new holes in the casing-tricky or take a rubbing and drill and countersink the drive plate?

[Diablo]

Is it definitely gear oil and not grease from the mag flange?

[J1MS]

From memory there are small castings that extend into the sprocket side of the casing which is where the original screw threads are drilled and tapped into, if you tried drilling the case with four new threads elsewhere, then you wouldn't have as much metal as is available with the original pressure plate screw holes to drill and tap into.

[Diablo]

Thats true Mark. I have done it before as a bodge but wasn't happy about it-although it did work.
If all the screws go in easy and sit well then my view is that its unlikely the casing is the problem.
Was there unburnt oil in the cylinder head and on the plug?
One thing to check even though the halite washer is being squashed is that the screws are not bottoming out on the threads. This will be evident if you fit just one screw but are able to move the seal plate. This has happened recently with the MB plates although I don't think it was anything other than a rogue plate.

[Special X]

Could be that as MB plates are (intentionally) very slightly thinner than std ones. Easy fix though - just take a (very) small ammount off the end of the screws.

[wack 63]

Funny you say that as I did compare the MB plate to a SIL one and it is thinner and the spigot that crushes the washer is lower but because the washer was crushed evenly I presumed it was ok.In the shed today so will check the thread depths etc and see.Found that the MEC crank was twisted and the flyweel is way out yesterday and the mag seal doesn't grip the crank so you may be right Diablo and the oil was actually melted grease.Head normal colour really but what made me suspect the drive side was the discolouration and markings on the web as centrifuge had flung the oil out but if the crank is out this could explain it .Thanks