Idle Help?

[evan_calgary]

Trying to adjust the idle on this bike and its a bit funny so figured I would pose the question.

The bike did not idle previously. Started and runs fine on the choke but dies quick quickly once off idle. I have adjusted the idle knob/screw and it seems to either sit at 3k or dies with a quarter turn of the knob. Further to the right and the idle will move higher.

Any thoughts?

This is a 600 motor in a 88 Genesis. From my reading carbs should be same as 400.

[TomcatMJ]

sure, the 600 carbs are equivalent to the 3en carbs,but with other jetting....maybe you will have to check if the carbs have the correct jetting, and at this point also check for clogging in the jets, jet-needles and needle-jets/emulsiontubes wearing, fuel valveseats and valveneedles wearing,and the gaskets state because you can only read the size of jets when the carbs are opened and then its the perfect time of checking the state of the other carbparts,too

[evan_calgary]

Jetting is fine on the main and the needle. No hesitation or other problems indicating jetting issues. The majority of the items you mentioned would cause problems elsewhere in open throttle positions. No flooding or lean state or leaking fuel, so needles should be fine.

Possible the idle air or the pilot is clogged but I would not expect the idle screw to have any influence at all in that case. Wondering if others have experienced similar conditions.

I didn't really want to take off the carbs but its looking that way. Trying to see if I possibly missed something here.

[TomcatMJ]

Did you try to turn the idle-screw just 1/16th or 1/8th? At my 3BF (the usual US-400) just a 1/16th too much would let it rev suddenly upwards or starve,depending on the direction...best might be let it run to normal temperatur with help of the choke and then wear a glove to avoid burning your fingers and try to set the screw...and check if the choke-mechanics work well and don't stuck somewhere
Other thing: Did you check the carb-boots for possible vakuum-leaks or proper connection?

[evan_calgary]

That's the sort of info I was looking for Tomcat. Thanks! I am actually turning the screw since the whole mechanism is quite tight. If it is just a 1/16th between dying and surging I will have to keep messing with it. That appears to be the case here I just found it odd such a small adjustment would make that difference.
Compared to my GSXR 1100 with 41FCRs, I can make a full turn adjustment and it is gradual versus the more on/off nature of the impact on the FZR.

I wanted to see if this was normal which is appears to be. Saves me tearing off the carbs. May need to get some more penetrating fluid in the mechanism.

Overall I actually find the FZR motor revs very quickly which is nice. These bikes must have relatively small flywheels perhaps?

[Evilchicken0]

Balance the carbs. Sometimes the cable from the idle screw can get a bit sticky so a small turn does very little then it snaps around. Try taking the screw off the mounting so it doesn't kink as much.