Please Help. Urgent

[BASS-TREBLE]

My friend has unscrewed this thing (pic) for no reason but put it back in and now the bike won't idle happily and has a little tune which I can only describe as a turbo winding up lol. Kinda windy.

What i need to know what is it and why would it affect the idle etc?

It is 'Urgent' as it is his transport to school.

Thank you guys

[Steam]

That's the Cam Chain Tensioner. It shouldn't be removed. It needs to be correctly tensioned. Did he?

[FilthyLuka]

okay, pay attention

That is you cam chain tensioner, it works on a spring. To install it properly, uninstall it, take of that little rubber end cap, insert a flat blade screw driver. Wind it anti clock wise (i think, might be the otherr way) as far as possible, if you take the screwdriver out it will spring back to where it was orriginally.

Wind it all the way in, keep the screwdriver in place, blot it in, remove screw driver.

Done

[R6_kid]

You must be the biggest pimp in school, riding around with all the chrome!

[BASS-TREBLE]

okay, pay attention

That is you cam chain tensioner, it works on a spring. To install it properly, uninstall it, take of that little rubber end cap, insert a flat blade screw driver. Wind it anti clock wise (i think, might be the otherr way) as far as possible, if you take the screwdriver out it will spring back to where it was orriginally.

Wind it all the way in, keep the screwdriver in place, blot it in, remove screw driver.

Done

thanks. just went to his house and managed to get it right. it has to be turned clockwise to compress the spring.

And about the chrome, its what makes a gn look like at least something, before it all flakes of.