Fast idle plunger
 

This might be one for Kev.........:sign4:
I understand that the fast idle plunger built into the bottom of the throttle body expands and decreases with the heat of the surrounding coolant but am curious as to what exactly happens. Does this allow more air in, or is there another channel that lets in extra fuel when open similar to a conventional carb.?
Thanks guys.

All in the ASK Kev section in detail with photo's

You are right as the coolant temp rises the bellows expands & closes off the pilot air intake port until operating coolant temperature is reached, then the intake port is closed fully & the bike idles off the open throttle plate only.

In the warm up phase air is feed through the idle port & around the throttle plate. The bellows is adjustable & set to obtain the correct cold start idle speed.

Thanks Kev, what would we do without you!
Thats brilliant
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