So I took my friend bike up there to have the oil changed on it it only has about 4,000 Mi on the bike. My friend said he lost the washer on the oil drain plug so it has a little oil leak & it only cost a dollar to replace please have them replace it. I get a call from a mechanic saying he needs to talk to me, I call him back & he said I have it taken apart & I think your oil might be leaking by the sproket but I really think its the oil pan gasket.