Hey,

I have a XR650L and have had all the US emissions crap taken off and had it dynod etc whilst replacing the stock can with something a little more fruity from XRs Only to gain a bit more power.

The only things is that oil is leaking out of the air-box. It seems like the engine breather tube now feeds directly into the airbox rather than being fed through all the emissions stuff that I have taken off. I am sure that this is not a problem - more a ´charachter´type thing of the bike (as long as I keep an eye on the oil level etc) but am interested to see if anyone thinks differently.

In terms of quantity of oil coming out - after a days ride there is about 10 drops leaking from the air box cover.

Cheers for any advice

Try to route a longer pipe or maybe an oil separator like the CB900 of old used to employ. It depends a lot on how the pipe is run, how much space you have for mods and how much oil comes out into the airbox but it's best kept where it comes from.
If space is a concern: I once made a separator myself welded from ss tube and sheet and stuffed it with a bit cut off a steel pot scrubber to make it more efficient. Cut a piece out of the breather pipe and hoseclamped it in between

Cheers for the advice and suggestion. I will break out the toolkit and give it a try.

Many thanks.