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cleaning the carburetor

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Hi All,

I have done a search and came up with nothing. But I have seen a article someone posted about cleaning the carby with pics and everything on the fcr carb.

Does anyone have any good links?

My problem is that my bike doesnt need the choke to start (and its winter in AUS), i have a feeling it is running rich, but first I want to clean the carb out and start over. I have an adjustable fuel screw coming in the post now, and checked the screw that is currently in there and its at 1 1/4 turns out?

Any suggestions?

PS I havent taken the bike out yet as I am still waiting for my fricken chain to be delivered (taken over 4 weeks now :ride: )

I think the previous owner had a problem starting with the hot start when the bike was hot (possibly still too much fuel :thumbsup: )

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doesnt sound like dirty carb to me.sounds like rich pilot jet.

what bike?current jetting?

2001 yz250f. Stock jetting and stock everything else! I did think it was rich on the pilot jet? what about the pilot air jet blocked?

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Try pulling out the pilot jet & cleaning it with carby cleaner if you want to eliminate it as a possibility. You haven't over oiled your air filter at any point perhaps? If so give it a good clean.

Adjust the fuel screw out to make it leaner if you haven't already tried this. Greater than 2 1/2 turns out would sugest your pilot is too big.

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Try pulling out the pilot jet & cleaning it with carby cleaner if you want to eliminate it as a possibility. You haven't over oiled your air filter at any point perhaps? If so give it a good clean.

Adjust the fuel screw out to make it leaner if you haven't already tried this. Greater than 2 1/2 turns out would sugest your pilot is too big.

I thought I had to screw the fuel screw in for leaner conditions?? So do I have to go go to say 1 3/4 turns to make it leaner? :thumbsup:

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I thought I had to screw the fuel screw in for leaner conditions?? So do I have to go go to say 1 3/4 turns to make it leaner? :thumbsup:

Yeah you're right; IN for leaner on a 4 stroke. (Just the opposite on 2 strokes, because2 stroke is air screw as opposed to a 4 strokes' fuel screw.)

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Great thanks for clearing that up, in for leaner, out for richer!

I bought a second air filter today and oiled it, so I will see if that will fix up my rich conditions tommorow. Fuel screw is on the way as well. is there any way to tel what size jets are in the carb? are they marked at all? I assume it is stock jetting..

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Here's the link with pics for getting to all the jets in your FCR. It's in the tech forums.

http://www.thumpertalk.com/forum/showthread.php?t=309069

Also, let your freshly oiled filter sit for an hour or so before you put it on the bike. This gives the emulsifiers a chance to evaporate. If you run it too soon, it can suck filter oil up into the air jets and clog them.

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just wanted to jump in here. That sounds like what happened to mine. Shortley,after I oiled my filter it has begun to stall at idle sometimes or if I blip the throttle of idle. Could I have over oiled or not waited long enough to run the bike? What is the best way to clean the carb. Keep in mind I never had an idle issue at all until I reoiled the filter.

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1. Remove jets per the link above. (be sure and count how many turns it takes to seat your fuel screw, so you can re-set it on re-assembly, and don't forget it's spring/washer/o-ring in that order)

2. Squirt through all jets and passages in the carb with carb cleaner (including air jets just below the carb's intake bell)

3. Follow up with clean, compressed air.

4. Re-assemble.

5. Ride.

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Hi all,

Just an update on the carburetor clean. Just finished it. Cleaned all main jets, and the two air jets as well. Also installed my adjustable fuel screw.

This is my current jetting:

Pilot jet: 45

I think its the needle jet (the other one next to main jet): 72

Main jet: 175s (whats the s for??)

Pilot air jet: 100

main air jet: 200.

Now bike doesnt stall when my fuel screw is turned in all the way... I think my bike is running rich (doesnt need choke to start in middle of winter here in AUS)

(still havent taken it out yet, I work weekends, but am taking it out on Saturday :thumbsup:

Should I drop my pilot jet down to a 42 or something??

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