Weird idle issue  By  superjew78 (Read 1,212 times)

[replyingto=natetheokay]natetheokay[/replyingto]I just got done doing a valve adjustment, they were way off. I set them both to .05mm according to the guide in the sticky at the top of the forum.

Seems to be ok now but the scooter is quite louder. I am gonna dial down the idle a bit and see if its ok

My engine was warmed up and i was trying to do that but i couldnt seem to get it right. I think its running much better now with the valve adjustment however it still sounds a bit loud. Maybe its just louder then i remember. I just started riding it again yesterday due to better weather.

any more suggestions?

the procedure I always us to set the idle mixture is:
make a note of how many turns it takes to lightly seat the mixture screw closed.
open it back to that setting.
( you can now set it back to where it was before if you end up with it running worse... )
set the idle speed to spec after warming up engine.
then close the mixture screw until rpm drops.
stop the engine.
make a note of how many turns it takes to lightly seat the mixture screw closed.
open it back to that setting. ( this is the lean rpm drop off point.)
restart engine.
open mixture screw.
rpm will rise as you go from too lean to the best setting then drop as you go too rich.
stop engine as soon as rpm drops.
make a note of how many turns it takes to lightly seat the mixture screw closed.
( this is the rich rpm drop off point.)
The ideal setting is right about half way between the lean point and the rich point.
tweak it one way or the other according to personal reference....
( a hair more open is where I prefer for easier starting, no dieing at idle when cold, no lean dead spot getting off idle when throttle is snapped open due to no accelerator pump.)
------------------------------------------
if the halfway point is less than 1 and 1/2 turns out you need a smaller low speed jet,
if more than 3 and 1/2 turns out you need a bigger low speed jet.
( if you can open it more than 4 turns with no rpm drop off due too it being to rich,
you have too small of a slow speed jet and the undersized jet is keeping it from ever going rich.)
------------------------------
choosing the diahram needle taper, Setting needle clip position, and setting main jet size also fall under how to tune it...

Like Alleyoop said, it might be running rich or lean.

I had idling issues similar to what you're describing when the needle valve in my carburetor stopped making a proper seal, causing the engine to run too rich.

I had no idea what was wrong, until I checked my air filter and found it soaked in gas and black soot on my spark plug.

I'd check for signs of a flooding carburetor. Maybe you could see if there is a trace of gas in the unit that holds your air filter.

See my post "Carb problem discovered: assembled wrong!"