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Build up Causes?

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Well my 04 cr250 runs pretty decent, but never they way my 01 cr250 did. It doesnt like to idle very well. It also seems to build up a little if lets say im putting around then go to take off it has to clean out slightly and even more so if i come out of the woods in some of the tight technical trails i ride it has to clean out even more so. What can be some causes of the building up? I know jetting can be one. I run 32:1, 30 pilot, 410 main, needle at 2nd air screw 1-1.5 turns out gnarly pipe, shorty, and v force 3. I have never re packed the shorty could that be a cause of the bad idling/buildup? I never really looked into it b/c when my silencer went on my 01 i had no power and terrible running conditions and my current bike doesnt have any of this

I used to run the 32.5 pilot in the summer but it seemed kinda messy on the bottom end and when i put the 30 pilot in it idled better and was more crisp. I do get some running on in the motor when its cooler outside, but if i go up to the 32.5 i get the poor bottom end or atleast did in the summer. It seems like nothing i do can get this thing to run perfectly. Could going down to 1st clip needle help then back up to 32.5 pilot or start with checking the shorty? Im not very good at jetting so i do not know what symptoms mean what changes in the carb. I have looked into articles about what ranges are affected by what items in the carb but i have never been able to get it right.

Any ideas?

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I had none of those problems with my old Mikuni, they can be made to run pretty clean and well. But I agree with the above, get the PWK A/S, it will run cleaner, more consistent, add bottem end with better throttle response. It really transforms the '02+ CR's

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Gotta put that clip at the top of the stock needle. Trust me , makes a world of difference. The stock carb works good, just takes time to get jetting dialed. I do agree though, the thing will not idle at all. But most of my race bikes (two-strokes) that ran perfect, didn't idle, or just barely idle.

Main 410-420

Pilot 30

Needle 1st position

Air Screw 1.5 turns out

The thing will rip.

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yeah, i def do not have the money for the A/S conversion, so right now im more so looking into either messing with this jetting, or going with a JD kit.

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i put a kehin carb on my bike with a jd jet kit.. the bike is 10X better.. well worth the money.. it idles better, the power is much more crisp and responsive

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yeah, i def do not have the money for the A/S conversion, so right now im more so looking into either messing with this jetting, or going with a JD kit.

I'll sell you my JDJETTING kit. IT's the JDH005 kit - Honda CR250R (04-07). Complete, and all parts & instructions still in original box. $45 shipped.

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Gotta put that clip at the top of the stock needle. Trust me , makes a world of difference. The stock carb works good, just takes time to get jetting dialed. I do agree though, the thing will not idle at all. But most of my race bikes (two-strokes) that ran perfect, didn't idle, or just barely idle.

Main 410-420

Pilot 30

Needle 1st position

Air Screw 1.5 turns out

The thing will rip.

I have a feeling this advice is pretty good.

although I don't have experience with the 3rd Gen Honda's I know the 2 mikuni eqipped 01s I've messed with needed to be leaned out so much on the needle it wasn't even funny (2 needle jets leaner and clip in 1st position was JUST enough at sea level), unfortunately I do not believe your needle jet is replaceable.

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I have a feeling this advice is pretty good.

although I don't have experience with the 3rd Gen Honda's I know the 2 mikuni eqipped 01s I've messed with needed to be leaned out so much on the needle it wasn't even funny (2 needle jets leaner and clip in 1st position was JUST enough at sea level), unfortunately I do not believe your needle jet is replaceable.

jet needle or needle jet, both are replaceable in the TMX

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jet needle or needle jet, both are replaceable in the TMX

The term replaceable might be confusing in regards to the needle jet in the 04'-07' vs. the 01'-03' TMX. Yes there is a part in the 04' carb called the jet holder that looks similar to the main nozzle (needle jet) in the 03' carb. And yes the jet holder can be removed, so it is replaceable, but there isn't a different size available so it isn't tunable like the main nozzle in the 01'-03' carb.

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The term replaceable might be confusing in regards to the needle jet in the 04'-07' vs. the 01'-03' TMX. Yes there is a part in the 04' carb called the jet holder that looks similar to the main nozzle (needle jet) in the 03' carb. And yes the jet holder can be removed, so it is replaceable, but there isn't a different size available so it isn't tunable like the main nozzle in the 01'-03' carb.

I see. Naive of me to assume 02s were the same as 04+ carburetors. Thanks for clearing that up.

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