Have you confirmed you do not have a vacuum leak between carb and engine? Sometimes it's difficult to get carb seated into intake tube. Have you installed air cleaner assembly back on? These bikes need the intake restrictions to provide enough vacuum to pull fuel in.
Carb rebuild gone wrong
I have a 2007 yz450f, I noticed it was running very lean initially so I back out my pilot screw and I didn’t want to go past three turns out as I have a lost a pilot screw before trying to adjust mixture for it running lean(yes I know how dumb that makes me). However the bike still ran fairly lean. A lot better but a little lean. As well when it warmed up I had a bit of hanging idle(lean condition) and when riding if I let off for more than half a second and went to hit the gas again there was about 1/4 second delay(bog). Because of all this I took apart my carb and rebuilt it. If you want to know how stupidly complex the carb for this bike is in reference to other bikes search up a FCR carburetor. Or watch this video
. After running the carb through an ultrasonic cleaner, replacing all the jets, and reassembling it and the bike(it takes a lot to get a carb out of one of these) it idles good, revs good in neutral, but when I put it in gear and let the clutch out it bogs instantly and dies(I know how to ride a bike it’s not operator error). WTF? Help please. My assumption is my pilot jet needs to go up in size. I’ve played with the idle and air/fuel screw trying to make it run better and nothings working. The only thing is before this I could ride the bike just fine. The thing Hauled ass. Wheelies in 4th gear, some small jumps, tons of fun. Just running lean. I assume that since it’s running WORSE rather than better I messed something up in the carb. For an advanced assembly of the carb watch this video
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air cleaner assembly is back on and looks to be fine. I checked the manual even and it’s assembled properly. Aside from a dirty air filter I can’t see any cause for concern. I intend to clean it but at the moment I have no cleaner. The carb is seated into the intake tube just fine all the way around, however the intake tube is cracked (weather checked like a tire). Nothing big enough that it could cause I leak I don’t think but maybe I should consider that as a possibility?Have you confirmed you do not have a vacuum leak between carb and engine? Sometimes it's difficult to get carb seated into intake tube. Have you installed air cleaner assembly back on? These bikes need the intake restrictions to provide enough vacuum to pull fuel in.
Take some brake cleaner and spray around the carb to engine area. If RPMs increase you have a vacuum leak.
Disclaimer: don't smoke while doing this.
Disclaimer: don't smoke while doing this.
Turns out the needle that came in my moose racing rebuild kit was a needle that is NFLR instead of NFPR. A .5 size difference. Which caused the issue. I changed it out and it’s running again.Take some brake cleaner and spray around the carb to engine area. If RPMs increase you have a vacuum leak.
Disclaimer: don't smoke while doing this.
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