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Like most bikes, it has to idle high to warm up before cracking the throttle to full!
Not exactly :)
All properly-jetted petrol engines need extra fuel when the metal is cold as the fuel tends to simply run along the cold metal surfaces as droplets which won't burn. Adding fuel or decreasing air richens up the air/fuel ratio to provide a volatile mixture that will burn regardless of the unvapourised fuel. Higher idle is a useful side-effect of this as it allows the engine to warm up faster, at which point all of the fuel is properly vapourising and creating a mixture that is far too rich for efficient combustion.
 

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My 1998 VFR has this as well. The '98/99 VFR's didn't have the fast idle circuit like the 2000 and up ones did.

I thought it was a choke at first as well, then I realized that was not possible. Then I read that it was actually just a fast idle (don't remember where) and it made sense.
 

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Not exactly :)
All properly-jetted petrol engines need extra fuel when the metal is cold as the fuel tends to simply run along the cold metal surfaces as droplets which won't burn. Adding fuel or decreasing air richens up the air/fuel ratio to provide a volatile mixture that will burn regardless of the unvapourised fuel. Higher idle is a useful side-effect of this as it allows the engine to warm up faster, at which point all of the fuel is properly vapourising creating and a mixture that is far too rich for efficient combustion.
Certainly a more in depth explanation. Note that there are no jets though. :)
 

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Certainly a more in depth explanation. Note that there are no jets though. :)
No, I was merely using the term "jetted" generically for fuel metering :)
I originally wrote "properly-fueled" but I figured that would confuse some :)
 

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The science: The hotter the engine runs the more efficient it becomes and the smaller the fuel/air ratio needs to be to have optimal burning.
If you have had a slightly rich carb engine and managed to get it hot like going up a mountain you may have fouled plugs by the time you got to the top, as air became thinner, engine hot from climbing, and accelerating out of hairpins without reaching high speed. 2stokes were notorious of this, and much more sensitive.
The venturi and jets in the carb do the same as the injector, they atomize fuel so the mixture becomes a uniform vapor/gas. As bladercr said this mist doesn't like cold metal which de-atomizes the fuel and makes it back into liquid drops, so the remaining mixture is actually too lean to burn at that temperature and pressure. The choke or enrichment circuit in EFI provides the additional fuel in the mixture so even when droplets form in the chamber there still is plenty of atomized fuel to burn.
You blip that throttle when the RC is cold (same thing has happened on blades) and you better have an other set of plugs if you want to go somewhere.
What I do is start it up and monitor rpms and don't let them go too high and keep lowering the knob to maintain about 1500rpm. Even in the summer it is good to use it as singles and twins run too erratic in low rpm for Efi and sensors to make up the difference and even if you can't read it they may hickup between 400-1000rpm. If they stall while the ernichment circuit was 100% they may also foul plugs.
You want a steady idle for the injection to work its best and to have that you need a few more rpms than warm idle.
 
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