Idle adjustment

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maddiedog
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Idle adjustment

Post by maddiedog »

LancPA_PCX asked in another thread (http://hondapcx.org/viewtopic.php?f=2&t=509#p7420) how to adjust the throttle. I did some research and read the service manual, here's a summary of my findings.


The PCX's idle is part of the fuel-injection system, in a component called the IACV. There is no traditional idle screw like on carbureted bikes.

Here is all the Honda / Helm Service Manual has on the subject:
engine idle (4-13).png
engine idle (4-13).png (261.93 KiB) Viewed 8469 times
And after the jump to that IACV...
IACV (6-46).png
IACV (6-46).png (326.25 KiB) Viewed 8469 times
What is an IACV? IACV = Idle Air Control Valve. This little thing measures air coming in, calculates the pressure of air coming into the engine, and using the RPM readings from the ECU, controls the air intake to set your idle.

You should never have to adjust your idle, or be able to. If your idle is off, either the throttle body or the IACV is malfunctioning.


If you're idling high, make sure your throttle isn't stuck slightly open. If it's not slightly open and you feel your idle is still too high, take it into a shop and have them measure with a tachometer (it should be 1600-1800rpm idle). If it is out of range, they will probably just replace your IACV.

One more thing -- the throttle body on the PCX is factory-adjusted, so if you think the throttle is stuck slightly open on the engine side, it might need replaced or cleaned.
Currently ride: 2011 Honda PCX 125 - Upgraded windshield and seat, keeping this one mostly stock
Previously rides: 2005 V-Strom DL650, 1974 Vespa Ciao, 2011 Honda PCX 170 (tons of mods - takegawa 170cc big bore kit, gears, etc), 1996 Honda Nighthawk 250, 1987 Honda Spree, 2000 KTM 125SX, 2003 Honda Silverwing, 2007 Genuine Buddy 125, 1998 Honda PC800, 2008 Buddy 125 (white), 2008 Buddy 125 (red), 2001 Honda Reflex, 1987 Honda Elite, 1988 Honda Spree, 2007 Yamaha Vino, 2007 Honda Metro, 2x 125cc pure-chinesium dirt bikes