Jetting and Throttle

[Tonyklem]

hey guys, couple questions.

1. when i pull my throttle back it sticks there. what are the possibilities for problems? i kno the slide is moving freely. think its the cable/twist throttle itself?

2. my jetting seems to be off. either that or my floats need adjusted. it seems that my bike fouls a plug ebout every ~30 minutes. IIRC it only happens when im 1/2 or more on the throttle. this leads me to believe its the main jet needing adjusted. there is a 172 main jet and a 58 pilot in there right now. should i go higher or lower for the main and should i just move in increments of 1 size?

thanks guys. and does anyone have the stock settings for the carb for an 89 cr250? the air screw is turned out a little over 1/2 turn. and as i said before thers a 172 main and a 58 pilot.

[E-man811]

1. also check to make sure that the throttle itself is free from obstructions.

Is the throttle housing too far on the bar causing the end of the tube to drag on the bar?
Is the end of the tube broken and the grip is rubbing on the bar?
Is there nasty smutz between the tube and the bar?
Is there a problem with the cable wheel inside the throttle housing?

Do not ride this machine until you find and remedy the problem.

Oh yeah, a dirty airfilter can cause your throttle to stick as well...

[crazyrydermx]

I'm pretty sure I have had ALL of the problems that these two have mentioned so far, at one time or another. There are so many possibilities, but make sure you fix this problem. Remember the Doug Henry crash....that was bad, and you don't want that!
Tell us what it was when you do fix it!

[Tonyklem]

will do

[Thumprding]

Check to see if there is dirt under the throttle tube also. Jetting. 1/2 on up and it fouls a plug. Is this after you have ridden below half throttle for a long time or does it happen when you open the throttle past 1/2.

The first case is too rich of a pilot jett and air bleed setting.
The second case is a combination of Main jet size and needle position/taper/diameter.

My suggestion is this. You can play with this for a while but if you purchase a JD jetting kit you will be done quick.

[crazyrydermx]

Originally Posted by Thumprding

Check to see if there is dirt under the throttle tube also. Jetting. 1/2 on up and it fouls a plug. Is this after you have ridden below half throttle for a long time or does it happen when you open the throttle past 1/2.
The first case is too rich of a pilot jett and air bleed setting.
The second case is a combination of Main jet size and needle position/taper/diameter.
My suggestion is this. You can play with this for a while but if you purchase a JD jetting kit you will be done quick.

It's not that his bike is revving crazily, it is that his actual throttle is stuck at being pulled back...like his hand is on it.

[Tonyklem]

yep, thats true crazyrydermx. also i got on it the other day and when its idleing there is a slight clunking/slapping sound. what do you think this could be?