Hi,
i am having a problem with my Machismo 500LB... it's engine is giving a knocking sound when i ride it and sometimes the knocking sound gives way to a loud screeching sound from inside the engine... the motorcycle is year and a half old and has done some 4000Km... all the four free services happened on time... the bike was last serviced in january.. after which it did some 1200 Km... i hv checked the oil and it is in good condition..
I have shown the Motorcycle to a mechanic working in a royal enfield showroom near my place.. he said its a tappet problem and gave me list of things that needed a change..
tappet valve
tappet guide
tamming gear(i dont knw what it is .. bt this hw he said it)
oil pump shaft
and some other small things and gave me estimate of about 4500 rs.

as this is the first major problem i am having with my bike so i am a bit paranoid...
so please someone help me
1. By letting me know is the diagnosis of the problem correct.
2. Does all the above mentioned things need to be changed in such a problem.
3. Is it normal for this problem to occur at such an early stage.
4. And can anyone advice me a good mechanic in Delhi close to the north campus area.

Apart from this i would like to know about some active Bullet Clubs in Delhi that i could be a part of.