Mystery oil leak
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- Settled in member
- Posts: 77
- Joined: Sun Jul 12, 2009 9:34 pm
- Bike owned: NC30
- Location: Bath
Mystery oil leak
My NC30 has developed an oil leak, but I can't work out where it's coming from. It's not constant and only seems to happen after the engine has run and is cooling down (I think). Say i go for a ride, come home, put the bike back in the garage, it won't leak oil then but if i come back to it 12 hours later there will usually be a small pool of oil - between a tablespoon and a teaspoon on the ground. It normally collects in the front of the bellypan and drips out there. I can't see any oil trace of oil above the front of the bellypan so don't think it's coming from a head / cam cover and it doesn't leak when I'm riding it. I have noticed that the sump has some oily residue on it, some of it above the gasket / where it joins the engine but it doesn't appear to be leaking. Also, it's not overfilled or coming out a breather (as far as I can tell). Any ideas where it could be coming from?
- Cammo
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Re: Mystery oil leak
Take the lower fairing off and have a good look.
If it's coming from the front it could be to do with the oil filter itself, other areas to look at are both engine side covers.
It's hard to tell until you have a good look with a torch, it will always drip off the lowest point it can run to. Usually it's because something a fastener is loose or threaded/broken.
If it only drips when the oil is hot (thinner) it shouldn't be a massive issue.
If it's coming from the front it could be to do with the oil filter itself, other areas to look at are both engine side covers.
It's hard to tell until you have a good look with a torch, it will always drip off the lowest point it can run to. Usually it's because something a fastener is loose or threaded/broken.
If it only drips when the oil is hot (thinner) it shouldn't be a massive issue.
"It's just a ride" Bill Hicks
- superlite
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Re: Mystery oil leak
Might also be worth checking that the oil level is not overly high. Could be evacuating via the airbox and overflow pipe into the belly pan. Unlikely, but doesn't hurt to have a look.
'Take it to the Back'
- banoffee
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Re: Mystery oil leak
fairing sides off, clean the engine then go for a blat and then come back to the bike when it's cooled down - should be able to see where it's coming from (with a torch if necessary as above)
mine was weeping out of the generator cover (small crack). was a pain to find to start with
mine was weeping out of the generator cover (small crack). was a pain to find to start with
attention 2 detail - bike valeting and more
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- Settled in member
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- Joined: Sun Jul 12, 2009 9:34 pm
- Bike owned: NC30
- Location: Bath
Re: Mystery oil leak
Cammo - checked the oil filter and it doesn't look like it's leaking but I will definitely check anything that could be lose.
Banoffee - Will go for a ride and check it out, i just hope it doesn't decide to leak when it's running, although from what I can tell it's something small as it's only dripping a tiny amount out.
Thanks for the advice
Banoffee - Will go for a ride and check it out, i just hope it doesn't decide to leak when it's running, although from what I can tell it's something small as it's only dripping a tiny amount out.
Thanks for the advice

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Re: Mystery oil leak
I'd take a paraffin gun to the block and make sure it was spotless.
Then Parked it with a newspaper underneath to find the leak.
Then Parked it with a newspaper underneath to find the leak.
xivlia wrote:i dont go fast on this bike so really do not need a rear brake.. /
vic-vtrvfr wrote:Ask xivlia for help, he's tackled just about every problem u could think of...