air screws

S

slim

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Joined
Feb 13, 2005
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15
Location
ontario
last year i put end dumps on my sxr and put some weight in my primary and jetting. raised my needles half space to 2 1/2 position. my air screws were only turned out 1 1/2 turns and i had a small
burple in mid range. this year i got some clutch info [thanks Turk] just wondering if i should drop my needles a half space or by opening air screws to 2 turns will this help my mid range.
 
Well those screws should be fuel screws as most yamaha's are, turning out the fuel screws will give you better throttle response and fix the low end bog when you slam the throttle open from idle. Personally, I have mine out to 2.5 turns out and it cleaned up the bog really well... don't think it did much for the burble. To fix that you should do some more work with the needle jet.
 
classic need for the reed stopper notch or reed spacers to cure the infamous yamaha triple midrange burble. How do your plugs and piston wash look after doing an extended midrange run and shutdown?
 
my mistake change up is right i meant fuel screws. i have reed spacers in it. plugs and piston wash looks good at full throttle chop. plugs look a little rich in mid range and sled feels a little boggie at half throttle when you punch it. i think i should drop my needles but that puts it back to stock settings and with pipes they should be richer i thought. maybe i'll wait and see what the 89l weights and 14.5 rollers do to it. there installed now but i havn't tried it yet. still waiting for some snow.
 
In my opinion (for what it's worth, remember I ask more questions than I answer) a little rich at this time ain't bad. Remember winters just getting started and it's gonna get a whole lot colder before it gets any warmer.
 
also, raising needles a 1/2 notch makes a huge difference on yamaha carbs. I'm not sure what the specs are for the end dumps but it may be too much fuel. Maybe someone else knows their specs for the needles, all pipe manufacturers are different.
 
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