how to tune keihin pwk 39 carb?

[Toyorider]

alright i really confused about carb tuning. how do i got about doing this. there is 3 things that i can change on this carb (main jet, slow jet, and the needle) also there is the air adjust screw. what do i buy to get this jetting dialed in. should i open up the carb and see what jets are installed then buy the next few up and down. what about the needle do i need to mess with that at all. does anyone know how much a shop would charge to get it dialed in? right now it got a ct 330 on it with a fmf pipe and im pretty much ride around sealevel to 1000ft.

[Toyorider]

also how do you measure the idle to adjust the air mixture.

[beerock]

try my setup...

i believe youll be a bit rich, what size carb etc, i need to know your motor specs and pipe etc ignition...

[Toyorider]

its a ctracing 330 kit with 39mm pwk keihin carb, fmf fatty gold series low end pipe and power core silencer, aluminum air box.

[beerock]

try my setup with a 173-175 if they make a 73 if not 172 or whatever

dgh needle,one clip from the top. 50 pilot, 170ish to 178

do all the recomendations then jet for WOT first with say a 175, with a new plug, get the plug tan color then jet for 1.4 to 3.4 throttle with holding the throttle at 1/2 with a new plug. check the plug and drop or lower needle if neccesary

good luck.

air screw should be about 1 3/4 to 2 1/2 out

[Toyorider]

so warm the engine up first then stick a new plug in. or warm it up with a new plug. then rev it to WOT (how long?) and check for plug color? then get another new plug to test the middle. what will the plug look like if its lean how bout rich. how long do i hold the throttle before checking?

[beerock]

NOOOOOOOOlol

get into like 3rd or 4th and hold it wot

yes warm the motor up if your smart yes warm it up on a old plug then pop inthe plug. if it starts to pop or bog do not hold it wot, do this until you top out in 3rd or 4th, i eould do 4th and just be rolling right where the pwoer band kicks in and hit wot until you top out then KILL THE MOTOR and coast to a stop and take the plug out to accurately read it you need a magnifine glass and look in the plug where the porcelain and metal meet (very hard to read this way) easiet way is to grind the threads off at the start and see the ring around the porcelain base(I just look inside i know what to look for.


heres a good article if you cant understand me

extreme pm'd me this the other day after i told him how to jet his pilot off the top of my head and i was dead on...

so is my wot jetting......(off the top of my head)

[Toyorider]

beerock wheres the article you listed. so once i hit wot in third or fourth kill the motor. how do i go about doing the middle range. so it looks like everyone still has the stock needle but just changed the clip if anything.

[beerock]

Originally posted by Toyorider
beerock wheres the article you listed. so once i hit wot in third or fourth kill the motor. how do i go about doing the middle range. so it looks like everyone still has the stock needle but just changed the clip if anything.

http://www.duncanracing.com/techfaq/Tech_keihin-carburetion-jetting.phtml

forgot im high on meds from surgery

and no he needles in your carb you need to find out what it is and tell me like i said previously. you should hope for a dgh like in my 330 (read the sig my jettign is in there)