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Did the 05 YZ250f have a lean pilot stock?

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I just bought a barley used 05 yz250f I mean the thing is showroom and I am not exaggerating.This guy rode it a couple of times in 4 yrs...but he let it sit without the gas drained and when I bought it it would only run with the choke on {with fresh gas] I cleaned out the carb and got it going with the choke off,but it is still backfiring at low RPM [like a lean pilot IMO] what do you guys think? anybody have an 05? also I don't like the damn card clamp where it connects to the motor,I tighten the thing as much as I can and it seems to damn loose to me,wich makes me think I might be suckin air,was this a flaw on these bikes?

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The pilot jet could be plugged up- remove and verify.

As to jetting, we had two 2005 YZ250s. One ran fine with the stock 42, the other one was more happy with a 45 PJ. Your results may vary.

The carb boot may be squashed out a little and need replacement. For your bike, that is not an expensive part (~$15 or less), so no need to fret.

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Mine sat the last 4 years before I bought it. Had to clean the carb 4 times to get all of the goo out of it.

I had to put in a larger main jet, move the clip down 1 notch and put an after market fuel screw to get it to run right.

Now its a beast!!!!

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wire tie the intake boot too the head have seen in the past intake boot fall off from caseing a double and a couple crashes if you look at a 07 and newer they bolt too the head

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Thanks alot guys.Ya know I had an 01 when they first came out and I never even looked at the carb boots and it was jetted fine what a shitty system {the boot] What baffles me is that the bike never had a wrench to it.When I asked the guy if he might have left a rag or something in the airbox he pointed to the air boot and said I've never been in there:smirk:"I had it serviced at the dealer"so I tell him to grab me a 10mm socket,there were no marks on the seat bolts the seat had never been off,I was expecting to see a disaster under there,but what I found was an airbox that you could eat your pasta out of and spotless filter with the original factory oil.So yeah I cleaned the carb out jets etc and this guy never touched the carb clamps thats for sure..and it is shit,that carb shouldn't buge so I'm gonna replace the boot and clamp since I'm pretty sure thats the culprit.I questioned the pilot jet size because my 06YZ450 was way off the mark out of the box.Anyway thanks again guys:thumbsup:

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