hey all... bought a dyno jet kit (fmf) useing the 146/148 (under 3000 feet) have a somewhat modified air box (not big holes but some small ones) cut the rubber flaps..and a DG excelarator full pipe idle circuit is great.. get to about 1/4 to 1/2 throttle and it starts breaking up by full throttle is puffin black smoke and backfireing i moved the needles up and down and with them at 1 slot from the top (2nd notch) it still does it... i know its to rich but.. even with the airbox lid off its still huffin and puffin... help please.. (btw yamaha if your listening... 2 CARBS SUCK A$$ on a SINGLE CYLINDER.. design it better next time!!!!!!

p.s. i followed the directions to the T the pilots are turned 3 out... no new pilot jets.. (yamaha dealer gave me the wrong ones)

 

One of the reasons for the dual carbs is that you get better throttle response with a dual setup than with a single larger carb.

It sounds like you right and are rich. The 146/148 dj setup is typically reserved for raptors with no air box lid and an aftermarket air filter. What needles are you running? Are they the stockers or dj needles and what size?

 

they are the DJ needles and whatever comes with the stage 2 kit.. and i do have aftermarket filter proflo?? or pro something...(foam) and what do you suggest.. the 144/146? maybe before making any adjustments i will clean the filters and apply the oil correctly to them.. just to make sure it isnt that.. but other jet combo's/needle settings will be gladly listened to

 

sounds more like a clogged main to me. If not that then inspect your carb boots real close for a tear especially along the area where you clamp them down.

/Jon

 

ok cleaned and checked carbs... even took the air filter right out.. still the same prpoblem with the 146/148 ??? ignition??? ughh i hope not.. anyones thoughts please

 

ok so im a frigin idiot.... while i was doing the jetting.. i also bought a ims direct shifter and have the sprocket gaurd and all that off currently.. well.. my dumb@$$ unhooked the reverse rev limiter cut off that was grounded to the case via the sprocket cover... DUHHHHHHHHHH