172 - problem high revs in first.

[stu_00]

I have a 2001 phase 1:

When going above 5000/6000 RPM in first The engine makes a sound that sounds like it is being restricted in someway, but no loss of power.

I have listen to some you tube videos and seems to happen in some other 172's.

Any Ideas, I am in London & so far away from the good garages. I might try and pay visit to Carlton garages as they are ace & carried out the cambelt change.

Thanks in advance