[Ianbruns]

I have a 2006 yfz 450 that I believe is stock besides an fmf exaust and a kn air filter with the lid on air box. It will start up easy and idle okay but once I try to hammer the throttle from an idle it will bog down, backfire and die if I don’t let off. if I ease into it then hammer the throttle it’s fine I figured it was maybe running lean so I checked the jets and it has a 178 main and a 52 pilot jet witch I thought sounded kind of big. Does anyone have any suggestions? Thanks

 

[Ianbruns]

I have a 2006 yfz 450 that I believe is stock besides an fmf exaust and a kn air filter with the lid on air box. It will start up easy and idle okay but once I try to hammer the throttle from an idle it will bog down, backfire and die if I don’t let off. if I ease into it then hammer the throttle it’s fine I figured it was maybe running lean so I checked the jets and it has a 178 main and a 52 pilot jet witch I thought sounded kind of big. Does anyone have any suggestions? Thanks

this is the color of flames it shoots if that helps

 

[kawa110]

Sounds like the famous throttle bog. Lots of threads about it.

For me

Ncqv needle
Jetted for my elevation and mods
R&D carb bowl
R&D fuel air adjuster screw.
Zip tie mod
TPS over ride
Tors over ride
Fuel customs intake.

Zero bog.

Over octaning will also flame out exhaust.


Sent from my iPhone using Tapatalk

 

[Ianbruns]

Sounds like the famous throttle bog. Lots of threads about it.

For me

Ncqv needle
Jetted for my elevation and mods
R&D carb bowl
R&D fuel air adjuster screw.
Zip tie mod
TPS over ride
Tors over ride
Fuel customs intake.

Zero bog.

Over octaning will also flame out exhaust.


Sent from my iPhone using Tapatalk

Does it sound like it’s jetted to high? I’m from Iowa if that is a big deal on jet size

 

[DVickroy]

That 52 sounds huge to me. I'd say it's getting way to much fuel. We're about to re-jet one in OK with a similar setup & starting with a 45 pilot and a 165-168 main. I'm not a jet wiz but with everything I've read and people I've talked to - nobody has suggested going that large with either one. Let us know what you do and how it works out.

 

[kawa110]

I’m at
175
45
90
Almost 1 3/4 out on air screw.

Fuel customs
Sparks exhaust
RPM’s ice cube cylinder

Been riding around sea leval to 3000’ without adjusting. Sometimes may backfire if I’m riding super hard. Head pipe only glows when I’m ripping hard at night. No glow during day.