Front sprocket lines


I have changed the front and rear sprockets (new washer on front sprocket) and chain on my WR450 2005 like 500 Kms ago and have been riding with no problems. The chain slack seems to be within spec, I have been measuring it since I changed the chain and sprockets.

I have been riding so far with the lubricant that came with the chain and then eventually I decided to put some Bel-Ray Chain lube on it. Since then, I don't know if it has anything to do with the Bel-Ray chain lube but I was checking the bike the other day and I noticed some sort of weird oily lines (not sure if it is oil though) on the front sprocket. So, I decided to clean the front sprocket and go for a small ride, as I stopped the bike again, I checked and those lines were there again.

I have also checked behind the front sprocket (without removing it) and there does not seem to have any sort of leak.

The lines look like this:


Does anyone have any idea what this could be please.

Any suggestions please.

Thank you.

Im not sure if you have the same problem, But I have a 05 rm125 and the oil seal behind the sprocket had worn and allowed oil to seep through, I just had to remove the sprocket and use a pick to remove the old one, Then grease up the new one and take a socket and a hammer and slowly tap in evenly. I hope this helps!

It is probably just excess chain oil / moisture / water that gets in behind the sprocket, and come out via the splines, and then centripetal force makes that pattern.

Thanks for the replies!

It is a bit weird because those lines only form at certain splines and not on all of them as you can see.

Just to be safe, how would I double check if it is oil from behind the seal or not?

Is it possible to check it without removing the front sprocket or is it better to remove it then check it?

If perhaps it is a oil leak, how bad would it be to ride like this a couple more times?

Thanks again.

I don't think it's your oil seal. I've just replaced mine recently, as it had been slightly leaking for about three weeks. And your's doesn't look like what I had. I think Krannie's right about yours being from the chain oil. If your oil seal was leaking, the complete area would have a light coating of oil/dirt stuck to everything. Maniac

If the seal is leaking, you will know it. Just look at your left boot......!

Thanks for the replies again everyone.

I will keep an eye on the amount of moisture that is coming out of there.

Just in case I need to replace the seal what are the part numbers (OEM) that I need to order? Where can I find those part numbers?

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