hi guys,
just picked up an ebay special?
rode bike home it power drops off topend, it also doesnt wheelie
when bike is at standstill it revs freely and sounds good.

not like other crrms ive had
any advice welcome

Need a lot more info before deciding that a rebore will solve your problems.

1st - Is the powervalve working . - Find out if you don't know.

A compression test is a far more accurate way of ascertaining bore and piston condition, there are far to many other things that could contribute to the symptom you described, such as, gearing, jetting, filter, plug, exhaust condition, etc.etc.
Fairly certain that this has been covered in the past, have a look on the search facility.
Mike

it has a dep front pipe that has been crushed towards frame, does look like it restricts gas flow a little but i dont think enough?

i do have a compression tester, just thought that the answer maybe simple....ill have to take a methodical approach