first up i would check the valve clearances, and reset them to .003" inlet and .004" exhaust.
next, i would drain the china oil out of the engine before it is even started and replace it with some better quality stuff.
10w40 motorcycle oil, must be suitable for wet clutches
here's an example-
Castrol/1 qt. 10W-40 4T 4-Stroke motorcycle oil (12146) | Small Engine Oil - 4 Stroke | AutoZone.com
once it's been checked over,
start the bike up and warm it up for a minute or so, then take it out for a ride.
keep the rev's down to 3/4 throttle maximum
take up up and down through the gears and don't labour it.
vary the speeds in each gear, and take it up a couple of small inclines too.
once you have been out about 15 mins bring it back and turn it off, let the engine cool down for 1/2 hour or so.
it might be worth checking/adjusting the carby mixtures too,
just to make sure it isn't running too lean or too rich.
so on your next ride do the same thing as above, but this time for 1/2 hour, then bring it back and let it cool.
(no need to recheck the carby)
usually the 3rd ride i will give it a bit more revs but don't hold it at wot for long if you can help it.
after half an hour or so, bring it back and let it cool.
once cool, drain the oil.
if you can, i would remove the clutch cover, and check the oil filter screen for filings etc before refilling it and going for the next ride.
now take the bike out and give it a bit every now and then, inclines etc, varied speeds etc.
and after another 1/2 to an hour, i usually consider it close enough to run in.
after another couple of hours i would change the oil again, you could probably stretch it out to 5 hourly oil changes after that.
i dont know if you have one, but you can get a cheap hour meter and stick it to the frame some where that it can still be read.
most are internally powered, and come on automatically when the bike is moved, or vibration etc.
some thing like this-
Inductive Waterproof Hour Meter FOR Marine ATV Motorcycle Dirt SKI Black | eBay
running in the engine till you reach 300miles is ok, especially if you want the engine to last a very long time
it is close on what the Oem Manufacturers (Honda etc) would recommend in their service manuals
but if you are anything like me, i find it hard to hold back,
it could mean i have to replace the rings etc a bit earlier than usual
