When my 250 is just idling the oil pump is pumping oil out the overflow tube. I know nothing about oil pumps! Any advice would be appreciated .  Looking at it again the oil seems to be coming from the engine overflow not the oil pump.

Hi BRETTS, i see you have two post going the same. No worries but might be best to pull one. Anyway you have me confused [but i'm old & easily confused to start with].
By engine overflow i'm wondering if you mean the gearbox [Transmission] breather tube & for that to pump oil out the Transmission would need to be full to the top. I've seen it done before so if its that then you're not alone.
If it's something else then more info needed please.

Thank you. I’m of the same age. The oil is coming out of the hose on the front LHS not the oil pump. I thought as well it might be overfull as it is worse on the side stand? What do you think. Thanks Brett 

Out of this hose?  Connects to #13 on the side cover.  That's the only hose on left hand side front I can think of.

Really need pics. But 'now' i'm wondering if you mean the breather on the magneto cover, in which case it must be full [of something] & getting swished around & out the breather--but surely not. If it's fuel then has it gone in to the motor through a carb or fuel tap fault [if turned off & still flowing--plus carb valve leak] then found its way through the crank seal. I'm out of ideas at the mo.
Ha, me & Mark typing at same time again haha.

Thanks gentlemen. That seems to be it but crawling around on the floor is not as easy as it was. I’ll pull it to pieces asap and get to the bottom of it. I’ll check oil levels. I’ll come back to you. Many thanks.Brett 

No it’s dripping from the rear LHS under the air hose between air filter and crb. I wish I knew how to take a photo 

Ok, thought Mark's Guess was spot on--so the plot thickens.
Back to the transmission theory & man she'd be full to the top for that to be able to happen.
So #15 then? has the fitting popped out of the case or the breather hose got off the fitting.
Even with that breather fitting out it still shouldn't do what you say.
Nothing should come out except air in & out if it wants, nothing major, just from gears & stuff whizzing around. Has a baffling sytem of sorts so any oil that gets up near there should be directed back down insde. That's talking 1 liter [1000mls from empty] [Not two liter plus guessing to fill right up.
Does your oil tank still have oil in?--not sure where i'm going with that question.
www.partzilla.com/catalog/yamaha/motorcy...974/dt360a/crankcase

Just came in from the garage. All fixed. Thank you for everything. I’ll see if I can post a photo. Brett 

I hope the photos upload.