Recently bought a second hand Honda Wave. It runs well, but I've no idea when it was serviced last. Is it best to have it serviced? e.g. Oil change, spark plug change, chain tightened, change air filter?. A post on here said we can work out if the bike needs an oil change by looking at the colour of the oil on the dipstick. If it's black, then needs changing. I'm not sure about this. Probably, needs changing before that right? (every 1000-2000 km? if you've kept track)
Also, some posts suggesting that if we use a local mechanic (not honda dealer) we should provide the oil then stick around (no pun intended) until the oil is firmly inside the bike. So, I'm wondering where to buy oil. Gas (petrol) station possibly? what kind should I buy?
Also, what about the spark plug and air filter? Presumably, the mechanic will have these to replace. Or should I buy it?
What would be the cost for this type of service? (Some posts suggesting we should ask the mechanic for the price beforehand, otherwise could be in for a shock).