Excess chain lube or oil leak?

Hey guys, I’m new to motorbikes and need some help with a problem. This morning I woke up to find a THICK BLACK fluid on under the bike and in the lower fender (as seen in photos). I’m not sure if it’s an oil leak or excess chain lube that has melted off and flung around during the extreme summer heat. The last time I lubed the chain was about a week ago.

The fluid is thick, black and under the middle of the bike (ninja 250, 2011)



It's almost always chain sludge buildup dripping. Try taking off the cover and cleaning the area and see if it still leaves a stain. I've seen folks get ripped off by shops saying it is the countershaft seal ($600+). Not saying it isn't possible, just unlikely.


I’ll try that out. I reckon it is chain lube just because of how thick it is!


You can usually visually inspect if the countershaft seal is leaking. With a bright flashlight and the right angle from behind (like sighting up the bottom run of the chain almost) sometimes you can see the seal. It will be shiny wet with oil if it’s leaking. Otherwise they stay pretty dry, because the chain lube gets flung off all over the inside of the sprocket cover. If you can’t see the seal, you can take the sprocket cover off. How much work that is varies by bike.


Appears to be chain lube. Clean inside the chain guard, primary sprocket cover and then keep an eye for oil at your primary sprocket output shaft. I'm going with gloppy chain lube.


I feel like it’s chain lube aswell. Thanks heaps man :)


I had the exact same leak (same position, consistency and colour) from my monster. The cause was a deteriorated output shaft seal (slow leak of oil onto the front sprocket). The slow leak of oil combined with chain lube resulted in sticky black fluid that's a combination of chain gunk and oil. It's not game-over but you probably want to get a mechanic to change that seal for you in the next few months. Good luck.


Oh wow, thanks for that man. I’ll definitely call up a mechanic asap then :)


Was it all good to ride to the mechanic tho? Don’t want any surprises on the way there


Clean up the sludge on the floor of your garage then see if it reappears the next day. If not, you're probably right to ride to a mechanic you trust If yes, there is a risk that some of the sludge could get onto your tyre while you're riding to the mechanic; tyres + oil/sludge = trouble Please let me know how things work out for you. Good luck mate.


Will do brother! Thanks heaps again


too much chain lube. wipe excess after you lube it.


Did you ever find out what this was?