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Leak Jet?

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Ok, so I poured through the jetting database trying to figure out why my wifes '05 WR250 runs so badly. It ran fine a year ago, so I checked the valves which are at the tight end of tolerances so i'm reshimming tommorrow. The bike flat won't start cold unless i spray carb cleaner down the plug hole. Took carb apart, seems clean. When i do get it running, choke must be on to start it again when warm. Then it runs like crap, bogs, chokes, won't idle, etc.

Here's what i've got in it currently,

Needle, Stock

Main 172

Pilot 42 Stock

Starter 72

Leak 95 (!)

Leak jet seems twice as big as it should be compared to others in Oregon are 40-42 for same year bike. BIke won't idle and bogs when throttled.

Ordered JD jet kit so i can use their needle and bigger main (175-185)

Any help would be appreciated, thanks.

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try 50 leak jet. Hard starting is most likely caused by the tight valves. Once they get tight sometimes the only way to start them is to push start them until you re-shim the valves.

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I just fixed my WR250 03 today by cleaning all the passages and getting a "FUEL MIXTURE SCREW" and I had to play with it a bit but i got it to run with no bog only thing is that the screw is almost all the way out...gonna try to get a 50 leak jet later this week.

Pm me if you need more info.. on my phone atm

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I just had the same problem with a "new to me" 05 250f. It was crackling and popping and bogging and only running with the choke on. I pulled the pilot jet and cleaned it out and it didn't solve the problem. Then I pulled the whole carb off and removed the pilot, leak and starter jets (I even pulled the needle) and sprayed cleaner through the passages until I could see the stream of spray coming out the other side. Then reinstalled all the jets and after spraying other potential sticky spots, I put the carb back in the bike. I knew right when I started it up that I solved the problem. Runs great again. This bike had sat un-used for over a year so it might have been a little more goey in there than yours (wifes). Good luck.

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I have a 2009 WR250 and it has a very serious bog when you’re riding the bike aggressive. When you come out of a turn grab a hand full of throttle and whack the clutch it falls on its face sometimes completely stalling the engine. It’s been this way since new and the dealer I bought it from said it comes jetted to lean. I changed the main and pilot jets the same as a YZ and it was no help. Has anyone else had this experience and would the leak jet be a factor at that power range?

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I have done all the free mods, I ride in NW Ohio at about 500 feet above sea level. I'm going to put a #40 leak jet in and test my AP. I'll let you know what happens?

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Ok, it's been a while but I thought I'd update you. I wound up going to a larger main jet. I think a 48? It took care of the bog

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Not a main jet, a 48 is a pilot jet and will make hot starts or restarting after a stall more difficult. You are way rich at idle now. That is the wrong way to resolve your problem. Pilot jet and fuel screw are for idle only.

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