MZ/MuZ Riders

Hi
Newbie to the Skorpion need help. Major oil leak. Fired the Traveller up the other morning and soon noticed oil pumping out from the bike all over garage floor. Knocked engine off but was making a few odd noises. Probably ran for no more than 30 seconds. Would guess probably pint of oil on floor.Got some good advice from guys on the Skorpion appreciation facebook page and found that the plastic blanking plug under the starter on the crankcase had come out. Cleaned up the area and replaced the plug using silicone sealant. Left it overnight topped up the oil and turned engine over on starter with no obvious leak. Fired her up and plug popped out with bike making some strange noises.
Question is what is causing the plug to pop. Crankcase pressure perhaps caused by a blocked breather? Other causes? With my basic mechanical skills I guess is the pipe from the bottom of the airbox disappearing to the top of the engine is the breather pipe, and if so it looks like tank off to access. Is there some sort of valve in the pipe or does it vent straight to the air box.
Before the problem bike was running perfectly so am a tad worried by the noise the engine was making (rattling sound) so I hope there is no permanent damage. First venture into Skorpion so was wondering if this is a known problem with 660 engine.
Looking forward to advice from the forum.

Bob

The hose that goes into the bottom of the air box should be coming from the crank case near the starter, and should have a valve/screen in it. Sounds like someone plugged yours maybe. Got pictures?

Hi edfmaniac. Thanks for the reply. Not had chance to remove tank yet, but pictures of pipe to bottom of airbox. Until remove tank can't really tell if it is the same pipe as comes from vent in front of starter. If so it must pass right over the top of the engine. Is this correct. There is also a blanked of inlet right on the bottom of the airbox, not sure what this does or did. Bob

The breather hose does indeed go right over the engine. It has an internal spring reinforcement to help prevent it collapsing in the heat up there. The connection to the bottom of the airbox looks right in your photo. I doubt that a blockage in this breather would pressurise the system enough to blow the blanking plug out unless there was something causing a lot of blow-by. Sorry that isn't very helpful, I'll take a look at mine later tonight to see if I an come up with anything else.

Both my crank case and CV carb diaphragm were vented to the atmosphere. There is no need to plumb the crank case to the air box other than for emissions.

Thanks Guys. Will check the breather first for blockage. Doesn't seem very promising. What else could cause a pressure build up in the crankcase to such an extent? Maybe connected to the odd noises.
Bob

Checked breather pipe with air line, good flow. Cleaned crankcase breather outlet seemed OK. Reassembled everything using silicone on the crankcase plug. Just turned it over on the starter and could fell pulse from breather pipe air box end as the engine turned. Not fired up as yet, will wait for silicone to go off, is there something mechanical that could knock the crankcase plug out? Thanks for your help. Not sure about firing it up though! Bob

Fired her up and all seems fine. With the breather off the airbox end I can feel a good pulse of air with every firing stroke. Blocked or collapsed breather seems to have been the cause. Have ordered a new one from Grahams. Thanks for the advice.
Bob