[HondaNAM400ex]

Good day

I have a 06 450r, seemed to be running fine but a little while ago, it started missing on wot. Fiddled with the fuel screw but nothing. Took it out without the airbox lid and performs like a beast. The moment I put the airbox lid back on then i get a bog on wot, only under load though.

Any ideas as to why it may be doing this?

The packing is burning up like it's not even there, 5hours and poof its tinny. I guess the fuel setting is too lean but I've got the fuel screw in at about 1.75 turns. Think i should go up a jet?

 

[SlammedRanger]

Well if it runs better with the lid off you are adding more air which would be leaning it out. So for what ever reason you rich on the main cercuit. Your mixture screw isnt going to make a difference at WOT at all so i would put that back where it was. If its idling smooth and starting easy at 1.75 turns out you need a smaller pilot jet but im betting it idles smoother and starts easier with the mixture screw further out. I would be checking valves and for air leaks on the carb also for why all of the sudden it wants less fuel on main jet. My .02

 

[misterclean59]

Your needle and it's jet/holder are probably worn from all the wear through the years. Or you are oiling the air filter differently than you have in the past.Perhaps the float is out of adjustment. It is running rich and these are some things I thought of real quick.

 

[retro]

I'd clean the air filter good and check any carb vents for plugged up hoses too. If they are all clear I'd look at the float height setting and the float valve for wear/leaking. Check that the SE valve hasn't stuck open, if yours is equipped... While the float bowl is off check every screw-in jet for any that may have loosened up and blow through the air bleed passages to clear those.... Have a looksee at the slide for heavy wear and if it looks like its wearing check the needle jet/jet needle for any oval-shaped wearing at the top where the needle pulls out of. If the needle shows a lot of wear the jet will be worn a lot worse...

Let us know what solves it if ya can...