Jay_G
13-10-2008, 04:29 PM
Guys i am looking for some advice on what to do about tuning my Mikuni's
background info.
kwak GT750 (basicly gpz motor) wiseco 810 kit 10.25:1 CR, 30 thou off the head, Mikuni BS34 carbs(factory fitment)with unifilter pods, 4-2-1 exhaust cut down yoshi, stock cams.
Engine has a big flutter/hesitation between around 3-6k rpm pulls quite hard after that if not a little bit fat with the fuel.
from memory i am running 42.5 pilots, drilled out mains to 1.6mm quite possibly a bit big, float set to specs in the book set with verniers then checked with the tubing off the bottom of the bowl, balanced the carbs with a mercury balance set and made fuck all difference. I advanced the ignition a bit the other day and it made it a little better, i found it was running a bit cleaner on 95 octane than 98 but have not run 95 since advancing the ignition as i think the static comp may be a bit high for an aircooled engine the run the 95.
My thoughts are that the cam timing may be out slightly or the float too high, i slotted the sprockets due to taking the 30 thou off the head but set them by eye with the notches in the end of the cams. and if you are familiar with the kwak cam setup there is a runner in the top of the cam cover the presses down in the middle of the chain and changes the timing, i set them with that in mind. i just have not got the gear to dial them in properly.
i am going to cut up an old cam cover to make a tool to press down the chain whilst still being able to see the notches and have another look at it.
I am going to throw it on a dyno in at bikecare in Newy shortly but want to get it reasonably close to start with so i dont end up with a $500 dyno bill.
I aso have clutch dramas but thats for another thread , so if you are familiar with kawasaki clutches the input is appreciated.
background info.
kwak GT750 (basicly gpz motor) wiseco 810 kit 10.25:1 CR, 30 thou off the head, Mikuni BS34 carbs(factory fitment)with unifilter pods, 4-2-1 exhaust cut down yoshi, stock cams.
Engine has a big flutter/hesitation between around 3-6k rpm pulls quite hard after that if not a little bit fat with the fuel.
from memory i am running 42.5 pilots, drilled out mains to 1.6mm quite possibly a bit big, float set to specs in the book set with verniers then checked with the tubing off the bottom of the bowl, balanced the carbs with a mercury balance set and made fuck all difference. I advanced the ignition a bit the other day and it made it a little better, i found it was running a bit cleaner on 95 octane than 98 but have not run 95 since advancing the ignition as i think the static comp may be a bit high for an aircooled engine the run the 95.
My thoughts are that the cam timing may be out slightly or the float too high, i slotted the sprockets due to taking the 30 thou off the head but set them by eye with the notches in the end of the cams. and if you are familiar with the kwak cam setup there is a runner in the top of the cam cover the presses down in the middle of the chain and changes the timing, i set them with that in mind. i just have not got the gear to dial them in properly.
i am going to cut up an old cam cover to make a tool to press down the chain whilst still being able to see the notches and have another look at it.
I am going to throw it on a dyno in at bikecare in Newy shortly but want to get it reasonably close to start with so i dont end up with a $500 dyno bill.
I aso have clutch dramas but thats for another thread , so if you are familiar with kawasaki clutches the input is appreciated.