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Oil Leak from engine casing

3K views 10 replies 4 participants last post by  kiko 
#1 ·
Hey I have a 2017 r3 with only 1600miles. I'm leaking oil from the engine casing meet behind the front sprocket. Its very slow but steady. it looks like a small rubber piece sticking out, i think part of the gasket. I wanted to know if any one has recommendation to fix this or do I have to do the whole engine apart and new gasket? Is there any product to seal or maybe weld it? I have seen a couple of people with the same issue but they are no longer online.
 
#7 ·
maybe weld it?
That's a definite no no.

It does sound like a gasket issue which isn't a big or expensive fix. Either than or the torque isn't even on some of the bolts, but that sounds unlikely if you can see part of the gasket.

I recall seeing some similar issues to do with oil leaking where a faulty gasket was the cause. I know you've already bumped an old thread but there are more on this site (somewhere).
 
#9 ·
If the oil is actually coming from the meeting line of the upper and lower engine cases (and not from the adjacent rear main seal that the transmission output shaft goes through), that is a BIG problem, properly solvable only by removing the engine from the bike, splitting the crankcases, cleaning everything up, and then re-applying sealant correctly. Given the significant amount of labour and that the bike is out of warranty ... you might get away with cleaning up the area very thoroughly (the sprocket will have to come off to get proper access to the area) and externally applying a small bead of oil-resistant RTV sealant over the crankcase split. There is about a 90% chance that this won't work but a 10% chance of it working is better than the labour involved in pulling the engine and splitting the crankcases ...

How much leakage are we actually talking about here?

IF this leak really is coming from the crankcase mating line, OR from the adjacent rear main seal ... either way, the leak is above the normal static oil level (engine not running) so it will not leak except while the engine is running.

This may be something that you just ignore. One of my other bikes runs well but it is an oil burner (it has over 110,000 km on it). Could it be fixed by overhauling the engine? Sure. Do I want to spend the money to do that on a bike that is essentially worthless? Absolutely not. The fix? Check the oil level every 1000 km and top it up. Oil is cheaper than a rebuild. Oil is cheaper than a new bike. If and when it actually blows up, that's when I'll buy a new bike.

If the oil leak is significant enough to represent a safety hazard due to oil getting on the rear tire, of course that is a different story. A drip every few minutes and only while the engine is running isn't going to do that.
 
#10 ·
Thanks, so it only leaks very little when the engine is running. It doesn't drip a lot but the area is very oil after riding.I'm gonna to take the front sprocket off. I think it might be the seal on the countershaft like you said. Because there is a small piece of rubber sticking out from that area. Do you think I can get away with sealant on the that part of do I have to replace the oil seal?
 
#11 ·
If it is the seal on the sprocket shaft leaking, then you will need to replace the seal. This is a common problem on all motorcycles that is often caused by tight adjustment of the chain. Many riders adjust the drive chain too tight and this causes stress on the countersprocket seal. Best to fix sooner than later or it could blow out on the road. Best of luck to you.
 
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