My son as got a CBR125 its an 08 plate with only 2400 miles. we at first thought he had an oil leak as after a ride out the following morning there are oil deposits left on the ground, It is now clear that the oil is coming from the breather. As you would expect the bike is just out of warrenty and the local honda dealer wont even look at it without me parting with some hard earned,  any suguestions to what i should do in terms of fixing it or diverting it so its not dropping into the fairing, my fear is it will splash over the back wheel as I have already noticed deposits on rim                                                                                                                                                                              

Just a thought, oil hasn't been overfilled ?                                                                                                                                                                             

thats one of my first thoughs and wish it had that would be an easy fix , also wounded with wrong grade of oil had been put in so i dropped the oil and changed it, if anything made it slightly worse.                                                                                                                                                                             

Can't say I'm familiar with the engine. Many breathers recirculate thro the airbox, could there be a blockage there somewhere ? Worst case it's pistons/rings causing crankcase compression. Tho it's very low mileage for that to be the case.                                                                                                                                                                             

I suffered this problem but a police caution sorted it out                                                                                                                                                                             

Hi
How long have you owned the bike and is this a recent development?
Check that the breather hasn't come off the airbox. It's unlikely that it exhausts into the atmosphere for emision reasons and should be routed into the air box. If it's breathing heavily (smoke and pressure) it sounds like a mechanical problem, rings and bore. Even with the low milage if it's been over reved the rings could be broken. If this is the case it would smoke heavily from the breather when the engine is running and have a loss in performance.

I was supprised to see the beather is just a tube out of the crankcase into the atmosphere,  but checked on new cbr125s in showroom and it would appear thats how they are , I was woundering if i could do a mod so it does breathe into the air box,  but not sure if all that would do is suck more oil out of the crackcase

have you checked the spark plug for oil leakage past the piston rings .        possible back pressure , does the engine idle ok                                                                                                                                                                              

easy thing to do is put pipe into a plastic bottle to catch the oil, won't cure it but will stop it getting on bike                                                                                                                                                                             

Dont know these engines,if it has a seperate oil pump system the small check valve could be passing so oil collects in the crank then gelts blown out of the breather when running.                                                                                                                                                                             

do a compression check thro the plug hole with a gauge a cheap one is not that expensive (should be able to find the figure in a manual or on the interweb) .A handy thing to do is keep a record of the reading do it every other service or so it will show u any probs as they are developing .You can tell if its valves or rings by sticking a bit of oil down the bore as the reading goes up because the oil temporarily seals the rings .If its running ok and u havn't lost any performance just cable tie the pipe to the swing arm - cheap chain oiler  simples !   Did the comp' check on a cb125 i had in no comp' at all even with oil down the bore took the head off someone had taken out the pistons ha ha ha