2008 Crf250r Wont idle

3/24/2021 4:02pm Edited Date/Time 3/26/2021 6:59pm
Hey i'm new here. I've had a 2008 crf250r since about April 2020, and the entire time it was weird starting hot. Finally got into the motor and found the exhaust valves were tight, and reshimmed them. Now it wont idle unless the choke is on or the idle is set uncomfortably high. Ive tried changing the jets, there is a 45 pilot, 178 main i believe, and 68 leak. Both exhaust were shimmed to 0.011, and the intakes were set to 0.004 and 0.005, which i'm pretty sure is within spec. I really don't want to have to do a valve job cause those are expensive i'm and unemployed teenager. I try to do all my own work as well instead of bringing it someplace.
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PNWRider
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Stanwood, WA US
3/24/2021 6:13pm Edited Date/Time 3/24/2021 6:13pm
Did you or the previous owner tear apart the carb?

It’s really easy to flip the floating plate on the slide, and it looks correct when it’s upside down. If you do this, it won’t idle and will run really weird. I only discovered this after tearing my 07 450 carb apart three or four times trying to figure out what the heck I did, lol.
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3/25/2021 4:46am
Since I bought it i have taken apart the bowl quite a few times cause i dont really know where to go afterward. I have no clue what a floating plate is. Is that just the float or...? I dont really know too much about carburetors and how they work. Also i forgot to mention that it has an R&D powerbowl and fmf exhaust if that should make any difference.
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Paw Paw 271
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Benton, LA US
3/25/2021 11:42am
Check your fuel screw setting. Its to be adjusted daily for best performance. Perform a leak test to be sure your valves are sealing. These bike do require valve maintenance from time to time and without it the bike just will not last.

Paw Paw
FGR01
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3/25/2021 12:24pm
Since I bought it i have taken apart the bowl quite a few times cause i dont really know where to go afterward. I have no...
Since I bought it i have taken apart the bowl quite a few times cause i dont really know where to go afterward. I have no clue what a floating plate is. Is that just the float or...? I dont really know too much about carburetors and how they work. Also i forgot to mention that it has an R&D powerbowl and fmf exhaust if that should make any difference.
https://jdjetting.com/fcr-carburetor-slide-and-vacuum-release-plate-squ…

FCR Carburetor slide and Vacuum Release Plate (square end MUST be oriented down)

The Shop

3/25/2021 1:45pm
Check your fuel screw setting. Its to be adjusted daily for best performance. Perform a leak test to be sure your valves are sealing. These bike...
Check your fuel screw setting. Its to be adjusted daily for best performance. Perform a leak test to be sure your valves are sealing. These bike do require valve maintenance from time to time and without it the bike just will not last.

Paw Paw
I've been constantly playing around with the fuel screw but i'll go try some more. I probably dont have the necessary tools to do a leak test. And thanks FGR01 for clearing that up. I'll go look to see if its in the wrong direction.
3/25/2021 2:20pm
Since I bought it i have taken apart the bowl quite a few times cause i dont really know where to go afterward. I have no...
Since I bought it i have taken apart the bowl quite a few times cause i dont really know where to go afterward. I have no clue what a floating plate is. Is that just the float or...? I dont really know too much about carburetors and how they work. Also i forgot to mention that it has an R&D powerbowl and fmf exhaust if that should make any difference.
FGR01 wrote:
https://jdjetting.com/fcr-carburetor-slide-and-vacuum-release-plate-square-end-must-be-oriented-down/ [b]FCR Carburetor slide and Vacuum Release Plate (square end MUST be oriented down)[/b] [img]https://jdjetting.com/wp-content/uploads/pbase/25566126.jpg[/img]
https://jdjetting.com/fcr-carburetor-slide-and-vacuum-release-plate-squ…

FCR Carburetor slide and Vacuum Release Plate (square end MUST be oriented down)

So i went back and took off the carb, i can see the plate. The side of the plate i can see (the side facing he front wheel) looks like the one in the image you posted. I can see the M, and unless im dyslexic, its not a W. The square end is at the bottom.
FGR01
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3/25/2021 3:16pm
Best bet with the fuel screw is to take it out completely and verify the proper installation and orientation of the spring, washer and o-ring. While it is out, blow out the fuel-screw circuit with carb cleaner. If the bike does not already have an EZ-adjust fuel screw, you might as well get one and install it. These are basically a must have on these bikes.



Another thing that is a common prob on these bikes, the hot start plunger gets corroded and gunked up with dirt and old grease. The cable needs to be free with some play and the plunger needs to be smooth and greased and close completely when the hot-start lever is released. If it is sticky or hangs up it leaks extra air and the bike will not idle correctly.
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3/25/2021 3:49pm
Ok thanks I'll try that. It also already has a ez fuel screw.
3/25/2021 4:03pm Edited Date/Time 3/25/2021 4:13pm
Alright i just took off the bowl again and the fuel screw. The only thing that came out with it was the washer shown in the picture. I then got out the spring and only one washer. I can't see that there is or was another in there so I'm going to assume there wasn't. I don't have any carb cleaner on hand but i do have some penetrating oil/lubricant if that will work in its place.
3/26/2021 3:13pm
Okay thank all of you guys for helping me. I fixed it, and it was one of two things. It was either the fact that I forgot to put on the air box vent line, or it was the fact that there were two of the washers and orings on the fuel screw. Either way, it’s done. Seriously I can’t thank you guys enough 👍👍👍
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davis224
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3/26/2021 3:49pm
Keep that air filter clean and oiled, and check the valves religiously. That generation CRF ate intake valves.
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Yeti831
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1/30/2020
Location
UT US
3/26/2021 6:44pm
davis224 wrote:
Keep that air filter clean and oiled, and check the valves religiously. That generation CRF ate intake valves.
I remember everyone and their mother installing Kibblewhite valves and springs out of necessity.
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3/26/2021 6:59pm
I'm just really glad that i was able to ix it. I was literally about to put in a bunch of money (for me at least) for a full maintenance, new plastics, graphics, wheels and tires. Really thought i was gonna have to use that money to fix that. later on i'll most likely do a top end and put some better valves in there. Definitely gonna buy a new air filter cause the one thats in there is pretty dirty on the outside.
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