CRF's Only Forums

hey guys im having some extremly
annoying trouble getting my fuel screw just right.
well i just rebuilt the top end like a week ago. the bikes valve clearences were perfect. i never touched the carb. and its a wiseco piston. same compression. well now the darn bike needs the hot start with choke off then with the hot start in then the choke and then i let go of the hot start and it idles. thats how i have to cold atart it for some damn reason. that tells me its running rich right? cuz the plug is black. well i adjusted the fuel screw and idle until it was idling perfectlty. but as soon as i take the choke in. it dies. it wont idle. and i cant seem to tell whwn the fuel screw is seated all the way in. i have stronger shorter fingers than most ppl so i dont know when i should stop turning the screw in. im afraid to dammage it. please help its very annoying lol

Sounds like you have two problems first is a clogged pilot jet and the other is your fuel screw setting. Do you have an aftermarket or stock fuel screw? Never the less, your problem sounds like a clogged pilot jet. The plug is black because your idling the bike with the choke on. Clean or replace your pilot jet and get an inline fuel filter. Turn your fuel screw in all the way (lightly seated) then turn it 1 1/2 turns out. This is a good starting point. You can't really properly adjust your fuel screw until your engine is at operating temp. When posting your posts make sure you include other mods such as exhaust, air box, cam, etc. Good luck. Let us know how it works out.

Thanks for the reply. The bike is completly stock lol i just put a wiseco piston in it. Only un stock thing in the bike.

Okay so i finally adjusted the screw to the factory setting. And it still does the same thing. I meen its got more power but still needs the hot start when cold and it smokes when cold.

Assuming that the piston and rings were installed correctly the next logical thing would be a clogged pilot jet. You,ll need to remove the pilot jet and blow it out with compressed air. You can remove it without having to remove the carb. Just loosen the carb boots and rotate the carb so you can access the fuel bowl.

Here's a picture of the pilot jet and main jet. Pilot is on the bottom.

http://www.crfsonly.com/forum/viewtopic ... highlight=

Umm awsome i hope thats the prob because the rings were installed correctly. Im 100% sure a clogged jet would still let it run when warm? And smoke when cold?

Well i cleaned the jet. There was a small amount of dirt in the carb. I cleaned it spotless. Then it still is giving me the same prob. It starts Slightly easier, but not one kick like before. And it still smokes when cold

Im starting to hate this thing

you are going to have to rely on the process of elimination at this point. replace the jets with new jets. make sure the fuel screw parts are correct, only one each and installed in the correct order. check your floating valve seal and plate. make sure they are installed in the correct orientation and the seal is not damaged from time or carb cleaner.

Well bike runs pristene like it used too now since i cleaned the jets. Thankyou for that!! I only have one more question. It still smokes when it gets started cold. If i blip the throttle a tad it puffs a little smoke. Once it idles for about 3mins its clean. What could cuase that

that's not uncommon. likely running a bit rich until the motor gets to full operating temps.

glad to hear shes running well again.

ken

Hmm makes sence. Do u think i should fittle with the fuel screw a lil more or leave it? But thank you guys both very much. This forum is the only place i go for questions. And theres not one time when ur wrong lol

yes, always adjust/fine tune the fuel screw based on current temps and altitude.

Will do thanks. How do i know when its perfect?