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'04 CR 125 not running right, anyone?

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I have a '04 Husky CR 125 that has started a problem that I just have not been able to find. Idles extremely high on start up (feels like too lean) eventually calms down and after good and hot will not idle (feels like too rich). This problem acts just like a air leak and was sure of it. I have changed the crank seal and no change. I had my dealer do a leak down test on it and it held fine. A little bit about the bike, it has a FBF 135 kit, FMF pipe/silencer, the Sudco magic needle is in it now I believe. I have a '02 WR 125 also and I am going to start trying diferent parts on it like the carb and intake next. If air leaks check out what else could it be besides carb? Jetting is very close to stock and seems not to effect it trying diferent jets. Thanks for the help in advance.

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This is a long shot, but a simple check. My '04 250 had a similiar symptom. The choke plunger was sticking and it would not seat all the way down always. I removed the plunger, used fine emery and oil to clean off the brass barrel, lubed it with a light grease and now it retracts well. It should pull up easily to apply choke. If not, it probably doesn't seat back down well.

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We have two CR125's. Both of them do the following. Upon starting they idle high and then calm down after a couple of minutes which let's me now they have warmed a bit and are ready to ride. The idle speed adjustment is cranked all the way in, I am not able to ge them to idle higher but they still idle good. It seems it is at the last of the idle adjustment screw limits. Still they both work just dandy.

You might have to richen up the pilot a bit to see if it slows down the high idle at cold start up. The bike will run leanest when cold.

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Thanks for the ideas! Flame you have your idle screw turned in that far? Are you running the Sudco needle or stock needle in your 125's? I am going to swap the carbs out to see if there is any diference when I get the '04 back. The '02 WR does not do this and the only diference between the two is the analog ignition and flywheel. I will take apart the choke and check it too. Keep them coming.

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I'm running the Sudco magic needle #2, as discussed in a thread a year or so back, link below. I can't remeber the specific needle # on the Magic #2. Magic needle #1 is also good. Hell stock is good, The bikes run great. The air screw is what you relly need to play with. The bikes are fussy about the screw depending on elevation, temperature and humidity. Easy to change on the trail. I always carry a little screw dirver to adj. the air screw and suspension clickers while out. I just stick it in my boot.

http://www.thumpertalk.com/forum/showthread.php?t=227661

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All my 2st's do this on and off. I use the kill button to regulate that first 10 seconds of miss-behaving. Do you turn the gas off when not riding. I always assumed some gas is pooling in the bottom of the crankcase between rides as causing this. My YZ250 will do this a lot but after that first 10 seconds it's fine.

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I'm big into turning off the fuel before I get back to the truck or shop. Time to die just about the time I get back. I like to run them dry that way as much as possible. Fuel just gums stuff up. I also use a lot of Stabil. I'm never sure how long it will be till I ride that particular bike again.

My sons bike sat for only one month and I swear the gas in the float bowl deteriorated in that time period causing varnish and it ran like sh#t for awhile than finally cleared itself out. You never know how long that gas you bought has been in storage before you bought it.

The guys in the small engine repair shops reccomend stabil at all times and then to drain the carbs when not in use. 95% of their engine running problems are due to varnished up carburators. A customer brings there weedeater in that won't run. They just do a carb clean it it will run fine again.

On my CR125 when I try to run it dry the bike starts to rev, higher as the fuel level gets low. Makes sense because it is entering a lean condition, just like the high rpm's experienced in our starting lean/high rpms condition. I never let the 2T run dry with out a load on the engine to control the RPMS because of this excessive rpms in a lean condition. The 2T's really never get totally dry in there I guess.

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I too have to regulate it with the kill switch when starting up when cold. I do not run them dry and usually do not turn the fuel off. I do drain them quite often though. The thing that gets me is the '02 WR does not do this so thought sure there was a air leak or problem with the '04. I raced the '04 with the problem at the Wisp GNCC and had quite a time keeping it running through the nasty muddy downhills. What a blast on the muddy grass track though with the back in dancing around on the pipe. Nothing else like it. I am going riding this weekend so I will have both to tinker with and test. I tend to agree that the magic needle makes it more pronounced. You only get one shot in the day to idle high when it is cold. After that it does not do it. If I can just get it to idle when hot I will not worry about the cold thing. I may call FBF tomorrow and talk to them.

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Interesting about the pooling in the crankcase. I never really thought about it doing that. I am going to try running it dry and see if it does it the next day turning the gas on before starting it. At least that would answer one part of it.

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