Whistling noise new bike

[greenman]

Hi I'm currently hearing a noise on my grubbee skyhawk 48cc Gt2b
Cant quite describe the noise like a high pitched whistling.

I think I hear it most a low revs and high,
When I have the clutch pulled in and WOT no sound whatsoever

I'm hoping that eliminates alot of possible problems.
And I tryed the search function but people with similar problems seemed to have it despite the clutch being engaged/disengaged.

Thanks in advance for any help, first post hi.

 

[greenman]

yes only when under load thanks heaps for the quick response, have a friend whos a bike mechanic will suggest these things.

 

[Venice Motor Bikes]

Head gasket?