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· Registered
401 Posts
Kinda hard to see what you are referring to... The dark black bolt? If so, I am pretty sure that bolt is bolting that ground cable to the engine. I don't think it even seals any oil in the engine.

What is probably happening is oil from your engine air filter is dripping down from the airbox onto the engine. Not to worry, mine does this too after I put too much oil on the air filter. But just to be sure, take a rag and spray on some degreaser, and wipe down everything inside that area, including the oil you see. The engine and the airbox. This way you can see if it continues to leak.

Then if it is actually from the air filter (which has oil on it by design) you probably just need to open the air filter slot on the side of the bike, slide the filter out, and clean the inside of the airbox with a rag, and wipe down the excess off the filter.

If I am totally mistaken, could you take more photos and add some circles or arrows to point to exactly what is leaking and where the oil is going?

Hope this helps!

· Registered
656 Posts
As Mike noted - there's no seal or amount of oil held by that bolt.

Clean it off, check that it's snug, and see what happens. Check the air filter and airbox as noted. Most likely, it dripped from there.

Keep a close eye on your oil level. If you run on the hwy for an extended period, especially in hot weather, you will lose some oil into the airbox from the crankcase breather system.

It's probably the most common cause-of-death of the little Ninja.

· Premium Member
84' Goldwing Aspencade, 91' EX500, 98' Ninja 250 w/ 17' 300 engine, 07 EX500
224 Posts
All the Kawasaki parallel twin engines use oil, especially the 250/300s. Due to high rpms at cruising speed.

So some oil is perfectly normal, you need to check the oil level all the time, low oil is the number killer of these engines.

Font Parallel Rectangle Art Diagram

Also note part #92192A is attached properly, this hose let's the oil drain back into the crankcase.
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