Pilot Circuit Question

[Desert CRF]

OK, I'm trying to dial in my pilot circuit but my fuel screw has almost no affect on carburetion. I can screw it all the way in and all the way out without changing RPM or throttle response perceivably. Is my pilot jet too big or???

Bike is an ’06 CRF450 with otherwise stock carburetor settings. Thanks guys.

[Wayward Son]

too big.what fuel screw are you using?

[SmallMonkey]

I'm having the same problem....

'03 WR450 using the "Storm Cycles" fuel screw (they're just up the road from me.)

The idle is eratic when set low, but smooths out when set too high.

I was using 50p then down to a 48p and even a 45pilot, but that didn't seem to help. Bike pulls like a raped ape everywhere else.

Bad Fuel screw? Smaller pilot again? (I don't think many guys are running a pilot smaller than 45.

TIA, Burned!!

[Wayward Son]

if the bike continues to ilde with the fuel screw full in,the pilto jet is to big.

[Desert CRF]

too big.what fuel screw are you using?

Zip Ty.

[wwrider]

if you look at the small stem on the zip ty fuel screw, the part that meters the fuel. it is shorter than stock, probably atleast a full turn. having same prob. try stock fuel screw.

[Chetaf]

I tried adjusting my fuel screw on my 2006 yz450f (stock jetting) last night and had the same problem. The bike came from Las Vegas and I am now operating it in Northern Utah at about 4500'. It pops a lot on deceleration, so I read the instructions on this forum on adjusting the pilot circuit and warmed up the bike. I was able to screw it all the way in to the seat, and while the idle slowed slightly, it continued to idle.

I assume this means I need a smaller pilot?

Eddie, what pilot jet do you normally use on a yz450f in Denver?

Thanks,

Chet

[Wayward Son]

stock fuel screw?

[Chetaf]

Yes, stock fuel screw.

[Wayward Son]

you sure it has the stock pilot jet? visually confirmed? some dealers think installing a bigger pilot jet is a cure for a bog.

[Chetaf]

I will double check.

[Chetaf]

I checked and it has a 45 pilot and a 170 main. I think a 160 main is stock for a 2006 yz450f, so I will probably need to go down a size or two.

So, generally speaking, does the popping on deceleration indicate a bike is rich or lean? I would think it would mean that it was rich.....but I have read a few posts on here that say lean.

Thanks,

Chet

[p505]

How hard is it to replace clogged pilot jet?

[p505]

It is in a wr250f 2005 model

[William1]

With the right tools and if you know what you are doing one minute. If you never did it before, it could take 30 minutes.