My buddy changed my sprockets on my 07 zzr 600 and its been leaking oil ever since does anyone no what it could be maybe a seal?

Well you have a leaking somewhere that is allowing the oil and coolant to mix, you may need to tear the engine down to find it. Does it have an oil cooler, if so that may be the source as well.

The easiest way to find an oil leak is to start with a clean engine. Clean the engine with a good degreaser (I've found the citrus based cleaners to be very good) while engine is warm (not hot) and let the degreaser sit on engine for a few minutes (follow instructions on bottle). Rinse off engine with high pressure water and let dry. Watch engine while a helper starts bike. The oil leak should be evident. The most likely culprits are a loose oil filter, oil pressure switch or an oil line, so pay particular attention to these.

You probably did.Don't know how,but you probably did somehow.

If you are having the bike on an upright position and you can see the oil level glass, then most likely it is correct. Check out for leaks.

Try blowing the radiator out from the engine side with compressed air to get rid of bugs and other debris. Make sure the fan comes on when it's hot. Check the filler cap seal to make sure it is building pressure in the cooling system. Worst case is leaking combustion products getting into the cooling system through a leaking head gasket or similar. There is a chemical test available that checks for that problem. Hope this helps!

Check you seal around there, most likely need replacement. Good luck.

It has standard threading. Turn counter clockwise to loosen.

hi buddy add 440mls of medium fork oil to it and go onthis site to show you how to strip them http://www.motorcyclistonline.com/howto/replace_fork_seals/index.html

hi buddy this is the oil seal on the shaft easy repair just take the front sprocket off and get a flat head screw driver dig it out and replace with a new one just dab some oil on the seal and slide into place thats it also clean around it because you dont want any dirt getting into gear box also replace engine oil

is their oil leaking down if so you blew a fork seal if not yes springs are worn or damaged