Author Topic: Idle circuit adjustments  (Read 382 times)

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Offline tore

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Idle circuit adjustments
« on: July 28, 2020, 08:56:56 AM »
Pilot jets in the Mikuni carbs should be named idle jets since that is the real purpose of those jets. There is a rule that the correct pilot jet is found when engine has the best idle with the air screw 1-3 turns out from lightly seated.
I have experienced that while adjusting the air screw, the idle needs to be maintained (you can not possibly adjust the air screw if the engine stopped running...).  After some adjusting ending up with a nice idle and the air screw 1-3 turns out. Happy...? Well I figured that if the pilot jet is way too big, there is a possibility I compensated by adjusting the throttle to open up too much.  Still with the nice idle maintained. This can easily be checked by flip the choke open. If everything is ok the engine gurgles and die off. If the engine start revving 3k or so the throttles are opened too much. There is a need to install smaller pilot jets!
 
Tore

RD350B (Indonesia) 1975
BMW R1150GS Adv 2004
HVA Roulette 1957
NV 125 1955
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