normal?jetting off maybe?

[JKWGA400EX]

hey,i have no idea what kind of jets im runin in my 450,the guy i bought it from had another guy do i t for him and he doesnt know what size he put in or anything.ok i dont know if this is normal or not,but here goes.if i run in about any gear and let it deacelerate theres a slight backfire(nothing loud just a little back fire like big old loud trucks sometimes have at deaceleration)kinda like a slight pop and crackle,it sounds really good too,but im wondering if this is normal.also when idling if u jam gas as hard as u can( in nuetral)and as fast as u can realease it it will bog alittle or die.but while riding i dont think it ever bogs.is this nothing to worry about and normal or should i screw around with the jetting?
oh,and how do u replace the spary plug on a 450r?i pulled the "cap" off the spark plug,and this long blue tupe came out,is it in there,how to get it out?srry for the long post.

-jared

[quadwanter]

hey i just got my used R the other day and mine does the same thing, my friend says its just the air/fuel screw that needs to be adjusted not a big deal or anything. If you get yours fixed tell me what you did...i'll do the same:cool:

[JKWGA400EX]

k,i think i'll take a look today after work.

thanks,
-jared

[bwamos]

If the air/fuel screw doesn't change it enough.. you may need to go up 1 size on your pilot jet.

[450R_lover]

Turn the air/fuel screw out about a half a turn and see if that fixes your de-accel pop. Mine was doing it this summer when it got hot. I just backed out the air/fuel a little and it worked. but i've also got a 50 pilot jet so... if it doesnt stop before you get to about 3/3 and a half turns out or so.. then you may need to bump up the pilot to a 50.

[Pappy]

That slight crackle on decel is right where ya want it