Idle Mixture screw Adjustments
#1
Idle Mixture screw Adjustments
Full Yoshi exhaust, Pro Flow & Pro Design foam filter, snorkel removed, 2, 1 3/4" holes in air box lid.
The jetting is 152 & 155 main jets. Needle 4th clip. Mixture screws just a shade over 3 turns.
Elevation 3500 ft.
Bike had a slight popping on deceleration, do not think that there is any exhasut leaks. Bike seems to be running excellent except idle fluctuates up and down a bit. My questions:
1. turning the mixture screws in will richen or lean the idle mixture?
2. What is the proper stagger for the two mixture screws? At factory both were 2 1/8.
3. Which carb would get the bigger stagger, right or left?
4. Jetted to 160 & 165 bike skipped at full throttle, went to 160 & 155 bike still skipped at full throttle.
Went 152 & 155 and bike runs perfect. But plug seems white after running plug check test.
I understand about jetting but I think that I am lean on mixture screws. I think that I need to turn them in to richen the mixture. Any help would be appricated.
03 Raptor
The jetting is 152 & 155 main jets. Needle 4th clip. Mixture screws just a shade over 3 turns.
Elevation 3500 ft.
Bike had a slight popping on deceleration, do not think that there is any exhasut leaks. Bike seems to be running excellent except idle fluctuates up and down a bit. My questions:
1. turning the mixture screws in will richen or lean the idle mixture?
2. What is the proper stagger for the two mixture screws? At factory both were 2 1/8.
3. Which carb would get the bigger stagger, right or left?
4. Jetted to 160 & 165 bike skipped at full throttle, went to 160 & 155 bike still skipped at full throttle.
Went 152 & 155 and bike runs perfect. But plug seems white after running plug check test.
I understand about jetting but I think that I am lean on mixture screws. I think that I need to turn them in to richen the mixture. Any help would be appricated.
03 Raptor
#2
Idle Mixture screw Adjustments
1- lean
2- I go about an 1/8 turn difference
3- Right more
4- At that elevation you shouldn't be rich with those adjustments. Maybe you have an air leak in the intake some where or a pilot jet with some crud in it. If everything is good then you might try 25 pilot jets.
2- I go about an 1/8 turn difference
3- Right more
4- At that elevation you shouldn't be rich with those adjustments. Maybe you have an air leak in the intake some where or a pilot jet with some crud in it. If everything is good then you might try 25 pilot jets.
#3
Idle Mixture screw Adjustments
How much do you think that I should try turning the mixture screws out?
I have some new header gaskets again, so I going to install them tonight and check for intake leaks.
I just had the carbs cleaned at a yamaha dealer two weeks before installing jet kit. But there was not carb trouble.
What do you think of the plug test? Thanks for your help!
03 Raptor
I have some new header gaskets again, so I going to install them tonight and check for intake leaks.
I just had the carbs cleaned at a yamaha dealer two weeks before installing jet kit. But there was not carb trouble.
What do you think of the plug test? Thanks for your help!
03 Raptor
#4
#5
Idle Mixture screw Adjustments
Sixsixt is right, go with a 25 pilot in both carbs. I had the exact same setup as you for a long time. I always had trouble getting the jetting just right until I went with 25 pilots. Made a world of difference. Start with 2.5/3 turns out, try it, move down by 1/2 turn each until you get the popping on decel. Then go back 1/2 turn out on each. That should get you running perfect.
If your headers are not sealed you will know it. You will hear a funny loud higher pitched exhaust sound coming from the front of your engine.
I switched to an Edelbrock carb simply because of the pain in the A$$ of trying to jet the stock carbs.
Good Luck!
RR1
If your headers are not sealed you will know it. You will hear a funny loud higher pitched exhaust sound coming from the front of your engine.
I switched to an Edelbrock carb simply because of the pain in the A$$ of trying to jet the stock carbs.
Good Luck!
RR1
#7
Idle Mixture screw Adjustments
I started the bike cold, let it idle for a couple of minutes. Header pipes were glowing red hot.
Also heard a noise in the engine after idleing for awhile. Could this be pinging?
Checked exshaust for leaks & found one at the left header. Replaced the header gaskets.
Pilot Jets were clean, Do you still think that I am too lean on the pilot jets?
Thanks for your help!
03 Raptor
Also heard a noise in the engine after idleing for awhile. Could this be pinging?
Checked exshaust for leaks & found one at the left header. Replaced the header gaskets.
Pilot Jets were clean, Do you still think that I am too lean on the pilot jets?
Thanks for your help!
03 Raptor
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