Air-screw & Idle-screw problems

Joined
Mar 3, 2003
Messages
629
Likes
0
#1
I have a 98 200 and I have recently cleaned all the carbys components. Now it needs the idle screw ALL the way in for it to idle. Any ideas as to why? Also I have a CEL needle, 42 pilot and 155 main. What would be a ballpark estimate as to where the air / fuel screw should be? 0.5 - 1 turn out or more? I know it depends on alot of factors but just a rough idea will do because I cant get the idle to increase by adjusting air-screw. All I am trying to do is tune the pilot circuit. As always my thanks all for any replies and ideas. tREV
 

CaptainObvious

Formally known as RV6Junkie
Damn Yankees
Joined
Jan 8, 2000
Messages
3,331
Likes
1
#2
The amount of turns out for the air screw is dependant upon the pilot jet used and the atmospheric conditions at any given time. Just because you were 1 turn out on one day (90 degrees with 80% humidity) doesn’t mean that same setting will work when the atmospheric conditions change.

The real questions are…

1) Did you change something (for the better or worse) by cleaning the carb? Perhaps you dislodged some dirt from a clogged jet. Maybe the card wasn’t reassembled correctly. What caused you to clean it in the first place?
2) Has the environment changed to the point where you need a different pilot jet?
 
Joined
Mar 3, 2003
Messages
629
Likes
0
#3
[The real questions are…
1) Did you change something (for the better or worse) by cleaning the carb? Perhaps you dislodged some dirt from a clogged jet. Maybe the card wasn’t reassembled correctly. What caused you to clean it in the first place?

I installed new needle CEL & pilot 42. So I cleaned it all before reassembling. The bike runs very hard in all the circuits but I cant seem to find an increase in RPM by tweaking the air-screw. Because the idle is so low it is hard to tune the air-srcrew without it stalling. So how can I either increase the idle (remembering that the idle screw is ALL the way in) or tune the pilot? I beleive I tune the air-screw for the best throttle response but I would like to fix the LOW idle problem first.

2) Has the environment changed to the point where you need a different pilot jet?

No It was the same day. Same conditions. Thanks alot for your info... tREV
 

CaptainObvious

Formally known as RV6Junkie
Damn Yankees
Joined
Jan 8, 2000
Messages
3,331
Likes
1
#4
Ahhh, found the problem. Don't confuse the airscrew with the idle screw. The idle screw is the one with the spring on it. With the bike fully warmed up, twist the screw until you find the idle you like.

The airscrew only adjusts the throttle response from idle. If you are adjusting it to the point that you are affecting idle you have turned it in way too much.

With the idle set, adjust the airscrew until you get good throttle response from idle (and from a slow, idle roll in second gear). If you find that you have to turn the screw all the way in you need a richer pilot (larger number) jet. If it gets beyond 2 turns out you should consider a leaner pilot jet.

Hope that helps.
 
Joined
Mar 3, 2003
Messages
629
Likes
0
#5
Thanks. I know its definatly the idle screw. Its as far in as it goes and the idle is very low... Im still at a loss !!! Cheers all... tREV
 

CaptainObvious

Formally known as RV6Junkie
Damn Yankees
Joined
Jan 8, 2000
Messages
3,331
Likes
1
#6
Are your SURE you reassembled the carb correctly?
 
Joined
Nov 16, 2000
Messages
20
Likes
0
#8
Mine acted like that when my pilot jet was stopped up. Had to turn the idle screw all the way in to bypass the idle jet just to keep it running. I would pull the new pilot jet out and check or an obstruction in the idle curcuit.

What is your air screw setting now? I alsways start out at 1 1/4 turns out and adjust from there.

Mike