Im trying to fine tune my carbs on my 1999 zx6r, but I'm having trouble taking the first step. My current mods are Muzzy full exhaust and K&N filter. My jetting is 145 mains, 120 pilots, and needle on the 3rd clip. Idle air screws are 3 turns out. At idle it is a a tad bit notchy, but not noticeable unless you try hard to here it. When I blip the throttle the RPM's do not dip before it revs or hangs before it comes down, it has good throttle response but It smells like its running rich. Also when I'm cruising at around 7k RPM I notice the tach slightly fluctuating like it is struggling to go over 7k RPM but when I snap the throttle it responses fine. What should I adjust or change. I was told the needles a long time ago, but I want to be sure first because the last time I touched one I broke the jet holder.
Need help adjusting my carbs
1 - 4 of 4 Posts
Joined
·
8,243 Posts
Is this a G or an E model
pilot jets are not a 120 either, so look at those again.......... you may be talking the pilot air jet, not the pilot fuel jet
idle mixture screws are for fuel not air....
Did you synchronize the carburetors?
Are they actually completely clean throughout all the circuits, not just new jets installed?
You don't specify loads or temp etc as to when these conditions are most prevalent and if they get better or worse as the temperatures rise.
How many miles and have the valves ever been adjusted, and when was that?
Do you know whose needles (dyno jet, factory pro, Muzzy etc....)
pilot air jet size
pilot fuel jet size
needle
needle jet
main air jet
main fuel jet
can you say what all these are?
pilot jets are not a 120 either, so look at those again.......... you may be talking the pilot air jet, not the pilot fuel jet
idle mixture screws are for fuel not air....
Did you synchronize the carburetors?
Are they actually completely clean throughout all the circuits, not just new jets installed?
You don't specify loads or temp etc as to when these conditions are most prevalent and if they get better or worse as the temperatures rise.
How many miles and have the valves ever been adjusted, and when was that?
Do you know whose needles (dyno jet, factory pro, Muzzy etc....)
pilot air jet size
pilot fuel jet size
needle
needle jet
main air jet
main fuel jet
can you say what all these are?
its a G2 model. I cleaned the Carbs well. Not my first rodeo with Carbs. I jetted and cleaned my FZR 600 and that was a total b#$%$. Im just new to Kawi. I went to a kawi dealer and they looked up the stock jet sizes and they gave my the stock numbers. We talked and discussed the bike and they swapped my old jets with the new jets. I dont know what brand name but I know they were for Mikuni Carbs. The G1 and G2 came stock with needles that are adjustable http://www.partzilla.com/parts/sear...00-G2+Ninja+ZX-6R/CARBURETOR+PARTS/parts.html I noticed the problem around 73 degrees with my bike temp on the 3rd notch. There was no real load on the engine because I was cruising on the highway in 6th gear, i just keep the bike at 7k so I could duplicate the problem. And I know the main jets are 145 and the other jet is one step up from 12.5. I synched the carbs and I held back on the valve adjustment because I bought the bike in November and rode it through the cold months with no hard starts with 18000 miles on the clock and it now has 21000.
Joined
·
8,243 Posts
Alright;
So what has been done to warrant going up 3 sizes/2sizes on main jets? it came with 137.5/140 (pipe and air filter aint it)
Are the new jets Genuine Mikuni or some aftermarket piece of shit jet with different flow characteristics and thus who the fuck knows how it compares to the Mikuni real deal?
Why go up from the 12.5 pilot fuel to a 15 pilot fuel...........it has to be just absolutely pig rich at idle, especially at 3 turns out
So oem needles on the third clip..........I will have to look at the service manual on that one- I have not worked on a G-model in atleast a dozen years
73 degrees outside air temp?.........what about bike temp?--did it run better when cold or when hot?--if you do not know.......go ride it right after it has been sitting for overnight while the engine is cold, and see if it runs better then or once it gets fully up to operating temps---
7k in 6th gear is what 90 mph....so a reasonable amount of wind drag load, not just "coasting" type load..........any uphill at all or downhill--tail wind---headwind?
My guess..........based on what you did provide---------it is pig rich at idle and just off idle,
it is likely still too rich up top with the mains you have in (a pipe and air filter wont warrant those changes- the bikes are already too rich with the oe spec'd main jets on every bike that has ever been made in the past 30 years.... you can easily go back down to 140-137.5-even 135's and true main jet jetting would be more than adequate fuel supply
The oe needle if indeed it is the oe needle, and say the load at 7k is super light (ie slight downhill or slight tailwind or just a lower gear) I would say you have a lean miss there, but it could other things too, not even related to the carburetors
OE needles are notoriously late to start the taper, have too large of root diameter and don't taper fast enough......... Thus why 99% of the time they are throw away parts if you truly want to garner the right jetting throughout the range
You need to do the valve service adjustment pronto............ The very first service is by far out and away the most critical to do, as the valves move the most then.....if they are tight by more than a little bit- it will adversely affect performance and running in all areas of the rpm band
So go do your homework, and maybe you will have a decent riding bike when you are done.
So what has been done to warrant going up 3 sizes/2sizes on main jets? it came with 137.5/140 (pipe and air filter aint it)
Are the new jets Genuine Mikuni or some aftermarket piece of shit jet with different flow characteristics and thus who the fuck knows how it compares to the Mikuni real deal?
Why go up from the 12.5 pilot fuel to a 15 pilot fuel...........it has to be just absolutely pig rich at idle, especially at 3 turns out
So oem needles on the third clip..........I will have to look at the service manual on that one- I have not worked on a G-model in atleast a dozen years
73 degrees outside air temp?.........what about bike temp?--did it run better when cold or when hot?--if you do not know.......go ride it right after it has been sitting for overnight while the engine is cold, and see if it runs better then or once it gets fully up to operating temps---
7k in 6th gear is what 90 mph....so a reasonable amount of wind drag load, not just "coasting" type load..........any uphill at all or downhill--tail wind---headwind?
My guess..........based on what you did provide---------it is pig rich at idle and just off idle,
it is likely still too rich up top with the mains you have in (a pipe and air filter wont warrant those changes- the bikes are already too rich with the oe spec'd main jets on every bike that has ever been made in the past 30 years.... you can easily go back down to 140-137.5-even 135's and true main jet jetting would be more than adequate fuel supply
The oe needle if indeed it is the oe needle, and say the load at 7k is super light (ie slight downhill or slight tailwind or just a lower gear) I would say you have a lean miss there, but it could other things too, not even related to the carburetors
OE needles are notoriously late to start the taper, have too large of root diameter and don't taper fast enough......... Thus why 99% of the time they are throw away parts if you truly want to garner the right jetting throughout the range
You need to do the valve service adjustment pronto............ The very first service is by far out and away the most critical to do, as the valves move the most then.....if they are tight by more than a little bit- it will adversely affect performance and running in all areas of the rpm band
So go do your homework, and maybe you will have a decent riding bike when you are done.
1 - 4 of 4 Posts
Join the discussion
