new pilot jet, idle way fast: please help

[scottwagnermd]

Well, I just put in a 48 pilot (great service from TT store BTW) instead of the stock 50 on 2004 yz250. bike was fouling plugs like mad. happened to disconnect the tps sensor during carb disassembly. it was my first time into a carb and i won't be making that mistake again. will check it with a multimeter soon but it was marked so i was able to line it up fine.

here's my questions. bike sounds great, but it's running what sound to be 1/2 max rpms. i thought it might be just the carb cleaner and let it run for a while and it never slowed down. i screwed the idle screw WAY out to no avail. on a positive note, i do get some change in idle speed with the fuel screw, which i didn't before. my jetting is otherwise stock, new plug, checked for any leaks and carb is firmly in position. not sure i have the two nuts on the throttle cable on top of the carb adjusted properly...can you change idle speed with those like a clutch adjustment? i also sprayed through my new pilot jet with carb cleaner, but didn't have any compressed air. i don't think that would plug a pilot jet.

i'm going to disconnect the tps later and see if that makes a difference, but i don't think that's th eproblem. i am wondering about the throttle assembly and i'm going to go out and tear the carb apart again if none of you guys have any other ideas. Thanks so much.
cheers

 

[ellandoh]

make sure you didnt somehow cause the throttle cable to stick open at all or get any air leaks in the carb boots

 

[scottwagnermd]

thanks for the reply...throttle cable moves freely and snaps shut nicely. no apparent air leaks that i can ascertain...carb neatly tightened onto boots.

 

[ellandoh]

adjust the air screw in to 1/2 to 1 turn out from full seat and adjust idle screw. if you cant get her right then your new pilot is defective or the old one was the right size and was worn out and became rich. i would go trade in the one you bought and buy a copy of the original, youll get it then either way

 

[scottwagnermd]

all right, i removed the carb again and it looks like the slide on the throttle assembly is not closing all the way as if the throttle cable is not long enough. nice free movement with the throttle, just doesn't close the throttle assembly slide all the way. the adjustor nuts just above the carb are adjusted to provide the most length possible. i can't figure out why this would be the case when it was fine before disassembly. any ideas?

 

[ellandoh]

there is suppose to be an opening even when its closed all the way. if you twist the throttle and let it loose you should be able to hear it slam shut to the stops. if you still believe its not closing all the way, check to see there are no kinks and it is routed exactly the way it was, and the slack is the same as it was . check also while turning the steering all th way side to side

 

[scottwagnermd]

it's not shutting all the way to the stops (slide goes down about 1 cm further when not attached to cable) , routing has not been changed, no kinks and steering moved side to side. I can't give it any more slack as the two nuts on the top of the carb are as high as they can go. ???

 

[ellandoh]

uhhhhh..................check that the cable is clipped into the slide properly? i dont know that is all i can think of. get into the top of the carb and double check everything . also i cant picture in my head but are you sure the nuts go higher for more slack as opposed to closer ?? also when i put a new throttle tube on my rig i had a bit of trouble getting the slack out on that end, inside the tube.

 

[scottwagnermd]

throttle cable inserted into slide properly, took apart the throttle housing on the handlebar and all up to snuff. i just can't figure out how the throttle cable seems to have gotten about a cm shorter when I didn't do anything to it. yes, nuts go higher for more slack. thanks...i would love to get this solved tonight, perfect riding temps tomorrow.

 

[klikboom]

Does your throttle increase when you turn your handlebars? Did you loosen up the cable at the throttle perch all the way? Did you route the cable the same way it was before?

 

[scottwagnermd]

no change in throttle with handlebar positioning, no changes made to cable routing. did loosen the throttle cable at the perch as far as it goes and now i get nice closure of the slide. seems to run fine now, i just can't figure out how my cable mysteriously shortened an inch or so. thanks