I have a yamaha blaster 2004 it has a new wiseco piston and a uni filter everything else is stock. My friend rebuilt my carb and i think he put the wrong size jets in it because its doesnt run right when going slow. I checked the sparkplug and it was black so im guesing its running too rich i dont know wat size jets it has right now but i wanted to know wat size jets do you guys think i need to put for it can run good again any information will be good thanks.
Yamaha blaster jetting
- Thread starter XxSiNMoCxX
- Start date
Well you should have a 32.5 pilot and a 230 main. I would check the air screw before I took the carb off. Should be at 1.5 turns out from a lightly seated position. Post results.
With an aftermarket filter I would use a #240 main, #32.5 pilot and the needle on the middle clip.
Adjust the float and idle and plug chop.
Float level should 20 to 21.5mm on a stock carby.
you want to turn the carb and hold it on a slight angle to measure the float height, like shown here......
it should just barely be touching the inner needle, not depressing it,
It is possible to check the fuel level by attaching a length of clear plastic tubing to the drain nipple , lifting it up the side of the carby, and cracking the drain screw.
The fuel should show in the pipe to the level of the carb body above the float bowl gasket.
Idle adjusting.
Set float level.
Start with air screw 1.5 turns out.
Set idle screw so that it has some sort of idle. With TORS it is the big screw under seat on top of unit. With no TORS is is the brass screw midway down carb body.
Warm up motor and then set idle screw for a faster idle, 2000rpm+
Adjust air screw either way to get the fastest idle.
Adjust air screw a little at a time leaving 10 secs or until the motor to responds.
Re adjust idle screw for desired idle .
Before you make the plug chop run it is important that the float level is correct, the idle is set correctly and there are no air leaks in the system, otherwise the smoke ring may lie about the AFR.
WHEN ALL OF THE ABOVE ARE CORRECT PROCEED WITH THE FOLLOWING.
Warm up motor to operating temp.
Fit new B8ES plug, ride through the gears and hold WOT in 5th or 6th gear for 10 seconds, or as long as you can safely.
Switch off the motor and pull in the clutch, apply brakes to come to a stop quickly.
Take the plug out and replace the old one for the ride home.
Carefully cut the threaded end off the plug to expose the insulator.
There should be a smoke ring of a cardboard or biscuit colour around the insulator.
If it is non existant or a very light colour, you are lean and require a larger main jet.
If it is a lot darker you are rich and may go down a size in main.
I prefer to run a little on the darker side, I may loose a little power but it is worth it for the peace of mind that I won't need a rebuild so soon.
http://www.blasterforum.com/do-yourself-20/how-plug-chop-38674/
http://www.blasterforum.com/engine-13/plug-chop-how-vid-48226/
This is a good to go plug.
This one is a little rich, but I would run it, I like to be on the safe side.
You have to get up a reasonable speed so that you can get the motor to pull strongly.
Then hold it Wide Open Throttle (WOT) for 10 secs or as long as you can.
The idea is not to get speed but to make it pull strong at full throttle to get onto the main jet circuit.
I find I can safely do it on a short run by applying the brakes some.
If you have not enough room you can use 4th or 5th gear with good results.
Adjust the float and idle and plug chop.
Float level should 20 to 21.5mm on a stock carby.
you want to turn the carb and hold it on a slight angle to measure the float height, like shown here......
it should just barely be touching the inner needle, not depressing it,
It is possible to check the fuel level by attaching a length of clear plastic tubing to the drain nipple , lifting it up the side of the carby, and cracking the drain screw.
The fuel should show in the pipe to the level of the carb body above the float bowl gasket.
Idle adjusting.
Set float level.
Start with air screw 1.5 turns out.
Set idle screw so that it has some sort of idle. With TORS it is the big screw under seat on top of unit. With no TORS is is the brass screw midway down carb body.
Warm up motor and then set idle screw for a faster idle, 2000rpm+
Adjust air screw either way to get the fastest idle.
Adjust air screw a little at a time leaving 10 secs or until the motor to responds.
Re adjust idle screw for desired idle .
Before you make the plug chop run it is important that the float level is correct, the idle is set correctly and there are no air leaks in the system, otherwise the smoke ring may lie about the AFR.
WHEN ALL OF THE ABOVE ARE CORRECT PROCEED WITH THE FOLLOWING.
Warm up motor to operating temp.
Fit new B8ES plug, ride through the gears and hold WOT in 5th or 6th gear for 10 seconds, or as long as you can safely.
Switch off the motor and pull in the clutch, apply brakes to come to a stop quickly.
Take the plug out and replace the old one for the ride home.
Carefully cut the threaded end off the plug to expose the insulator.
There should be a smoke ring of a cardboard or biscuit colour around the insulator.
If it is non existant or a very light colour, you are lean and require a larger main jet.
If it is a lot darker you are rich and may go down a size in main.
I prefer to run a little on the darker side, I may loose a little power but it is worth it for the peace of mind that I won't need a rebuild so soon.
http://www.blasterforum.com/do-yourself-20/how-plug-chop-38674/
http://www.blasterforum.com/engine-13/plug-chop-how-vid-48226/
This is a good to go plug.
This one is a little rich, but I would run it, I like to be on the safe side.
You have to get up a reasonable speed so that you can get the motor to pull strongly.
Then hold it Wide Open Throttle (WOT) for 10 secs or as long as you can.
The idea is not to get speed but to make it pull strong at full throttle to get onto the main jet circuit.
I find I can safely do it on a short run by applying the brakes some.
If you have not enough room you can use 4th or 5th gear with good results.
Thanks for the replys i am new to this and is the air screw u guys are talking about the same one as the idle screw or are they two different things? Also my blaster doesnt idle i have to be giving it gas for it could stay on.
The air scre is the small flathead screw on the side of the left side of the carb. Your idle scre is under your seat. When you take the seat off You'll see a big box on top of the carb. That box will have a big flathead screw on it. Screwing it in (clockwise) raises the idle. Set the air mixture screw to 1.5 turns out and adjust idle.
Idle adjusting.
Set float level.
Start with air screw 1.5 turns out.
Set idle screw so that it has some sort of idle. With TORS it is the big screw under seat on top of unit. With no TORS is is the brass screw midway down carb body.
Warm up motor and then set idle screw for a faster idle, 2000rpm+
Adjust air screw either way to get the fastest idle.
Adjust air screw a little at a time leaving 10 secs or until the motor to responds.
Re adjust idle screw for desired idle .
I put the airscrew out 1 1/2 turns out and took it for a spin it ran really nice that solved my problem when going slow thanks. But when i turned it off i turned it back on and i tryed to fix my idle and now it revs up high and i cant bring it down and the idle screw just keeps on spinning it never stops i ordered a new throttle cable i think thats wat is wrong with it. If my steering is straight it keeps on reving up but if i turn it all the way to the left it stop so im guesing it is the throttle cable?
The cable is adjusted way too tight, I can just imagine what would happen if you turned the bars hard right.
