The carbs have been rebuilt a few month ago and everything replaced. I think I need to wind in the low screws and when I demand full throttle it takes a few seconds to pick up. WOT test?
FOR THE MILLIONTH TIME. THE LOW SPEED ADJUST IS
NOT to be used for ANYTHING except idle. idle is NO: blipping, babying, touching of throttle.
Idle circuit adjustment:
Go to a lake. Strap ski down to trailer. Put on truck parking break. start ski, let said ski warm up for 3-5 minutes.
NOW, set idle SCREW on carbs to what yamaha says, i think its 1250 +/- 50 rpm. aka get a tach.
make sure both carbs are the same # of turns out to begin with.
count all turns.
dont touch it for 20 seconds, if it starts to burble and dies cla clunk, cla clunk, its going rich.
turn in screws 1/4 of a turn or less at a time. see if idle goes up. if it does, turn them in more until it sounds like it wants to die.
turn back out from highest RPM point 1/8 turn.
unstrap ski. idle for 5-10 seconds. pin throttle, should be clean and crisp MINUS the loading of the water box.
POPOFF:
get a damn gauge, theres no way around this. either make one, search the forums, like a million threads on $10 and less adjusters.
go on the jetting page, to start with rough pressures.
rule of approximate thumb, somewhere in the low mid 40's to mid 30s for a single carb with STOCK flame arrestor with no screens removed.
aftermarket f/a is USUALLY in the 30's to mid-high 20's.
POPOFF TEST:
hold 1/4 to 1/3 throttle for 10-15 seconds. PIN THROTTLE, if it dies, or power nearly cuts out, POPOFF is too high, meaning a LEAN midrange.
if it doesnt try to die, but makes a WAAAAAAAAA sound that is no loss of power, but not really a gain of power, popoff is too LOW, meaning a RICH midrange.
once it neither dies nor bogs, low speed and mid speed are taken care of.
HIGH SPEED CIRCUIT:
pin it to win it, like a scrub. let go of the throttle after you kill it and smoothly glide onto your trailer (jk you won't make it on your trailer)
if your plugs look like those black slimy things in your post, you are probably about 2 mains high.
if they are grey, you are 2-3 mains low.
IF they are the color of a Filipino, or a properly TOASTED marshmellow, its good to go.
NOW:
your issue.
turn all screws on the b pipe in all the way except 1/2 turn out on the bottom. this is a baseline.
either get a $12 USB 5mm wide camera on ebay to make sure piston wash is there or pull the head.
pistons should have black built up on them everywhere except thumbnail sized shiny spots by each of the 4 transfers and 1 by the boost port. if the piston is super shiny and clean, it is either: really friggin rich, or leaking a small amount of water in, amounting to a steam clean effect of the piston.
pull the intake manifold and check the reeds for chips or other shiz that doesnt look right like lifting off the cage, cracked reeds, chipped reeds, cracked/missing rubber from the cages etc.
apply a light coating of grease on gaskets when reinstalling manifold and carb base gaskets and such.
