What is this piece on intake?

[HOBO4LIFE]

Can someone explain me what is that piece in the picture, because on my bike there is just shiny bit sticking out. Just wondering because I can't get my bike to idle.

[Mightyman]

Doubt it'll be anything to do with your idling. @Calum knows the rough science behind it but it's supposed to be beneficial for the engine in some way.

[Calum]

YEIS. Yamaha Engine Intake System. It uses the engines harmonic resonance frequency at a recession in the engines combustion phase to draw in a needed supply of oxygen. If it has been removed then you will not benefit from the performance gains. But it needs to be properly blanked off else it will cause a vacuum leak and won't idle

[HOBO4LIFE]

So does it add more hp? Will this fit my dtx? http://www.ebay.co.uk/itm/DT125-DTR-YEIS-Chamber-/122226147114?hash=item1c753eff2a:g:1VgAAOSwh-1W4Dwb

[Calum]

@HOBO4LIFE Oui Oui Oui.

Get the bike back to stock to try and sort it out.

[HOBO4LIFE]

@Calum This started to happen after carburettor was cleaned, by professional mechanic. Also I never had it.

[Calum]

@HOBO4LIFE Well then that sounds like your problem. The carb may not be setup correctly. There is an idle screw on the side that can be adjusted to correct the idle.

The YEIS is there for a reason.

[HOBO4LIFE]

Will that one fit? ebay link

[Calum]

@HOBO4LIFE Yep looks like a great price too