I had an oil leak from the oil tank in my mc21, also had a problem where the bike doesnt accelerate smoothly, instead at higher revs it 'stutters' and loses power.

I took it to a bike mechanic in Melbourne to look at it, he said it was running too rich, he fixed the oil leak, replaced the spark plug and gave it a 'tune' to make it run leaner. Cost me close to $200au.

Now i notice a problem that when i start riding it, i hear 'pops' now and then from the engine and it loses power for a second. After 5 minutes of riding this issue disapears. However i still have the problem where it wont accelerate smoothly if i gun it, just accelerates smoothly for a bit and then stutters, and sometimes stutters at low revs also.

Anyone know what the issues could be, so when i take it back to the mechanic i can have some idea what im talking about.

Thanks.