just rebuilt top end. valves new. have a fmf power core exhaust and powerbomb header. and all the hop up smog mods. also have the 'r' cam. cant get rid of flat spot. just wondering if anybody knows the correct jetting for this set up. person bought bike from did these mods. not sure if he touched the carb,
need carb help
Started by rasta, Jan 30 2012 04:31 PM
5 replies to this topic
Posted 30 January 2012 - 04:31 PM
just rebuilt top end. valves new. have a fmf power core exhaust and powerbomb header. and all the hop up smog mods. also have the 'r' cam. cant get rid of flat spot. just wondering if anybody knows the correct jetting for this set up. person bought bike from did these mods. not sure if he touched the carb,
Posted 30 January 2012 - 05:09 PM
What part has the flat spot. idle ,low mid, high? That will tell you which part of the carb need to be adjusted.
Read this and you will understand your carb a lot better. After you determine which area the jetting is off in then you need to know what is in the carb to begin with...the jets and needles have markings on them.
Read this and you will understand your carb a lot better. After you determine which area the jetting is off in then you need to know what is in the carb to begin with...the jets and needles have markings on them.
Posted 30 January 2012 - 05:37 PM
Jakeblues, on 30 January 2012 - 05:09 PM, said:
What part has the flat spot. idle ,low mid, high? That will tell you which part of the carb need to be adjusted.
Read this and you will understand your carb a lot better. After you determine which area the jetting is off in then you need to know what is in the carb to begin with...the jets and needles have markings on them.
Read this and you will understand your carb a lot better. After you determine which area the jetting is off in then you need to know what is in the carb to begin with...the jets and needles have markings on them.
Posted 30 January 2012 - 05:47 PM
you have increased the air flow, now you need to increase fuel to match.
You are probably going to end up increasing the size of the pilot jet. Most common increase is 42 or 45 pilot, and/or raise the needle. If the bike is older than 06, does it have the ap mod?
If you read the article you will see the needle circuit and pilot circuit do overlap. Also find out what your fuel screw is set to. Find it on the carb, count the turns as you turn it in til it gently seats. Unsrewing it gives more fuel, tightening less, you may be able to fine tune your flat spot away with the fuel screw, but the range is 1 1/2 turn to 2 out from the seat, less than that and you should install a smaller pilot jet, and more than 2 install a larger pilot jet.
You are probably going to end up increasing the size of the pilot jet. Most common increase is 42 or 45 pilot, and/or raise the needle. If the bike is older than 06, does it have the ap mod?
If you read the article you will see the needle circuit and pilot circuit do overlap. Also find out what your fuel screw is set to. Find it on the carb, count the turns as you turn it in til it gently seats. Unsrewing it gives more fuel, tightening less, you may be able to fine tune your flat spot away with the fuel screw, but the range is 1 1/2 turn to 2 out from the seat, less than that and you should install a smaller pilot jet, and more than 2 install a larger pilot jet.
Posted 30 January 2012 - 06:11 PM
Jakeblues, on 30 January 2012 - 05:47 PM, said:
you have increased the air flow, now you need to increase fuel to match.
You are probably going to end up increasing the size of the pilot jet. Most common increase is 42 or 45 pilot, and/or raise the needle. If the bike is older than 06, does it have the ap mod?
If you read the article you will see the needle circuit and pilot circuit do overlap. Also find out what your fuel screw is set to. Find it on the carb, count the turns as you turn it in til it gently seats. Unsrewing it gives more fuel, tightening less, you may be able to fine tune your flat spot away with the fuel screw, but the range is 1 1/2 turn to 2 out from the seat, less than that and you should install a smaller pilot jet, and more than 2 install a larger pilot jet.
You are probably going to end up increasing the size of the pilot jet. Most common increase is 42 or 45 pilot, and/or raise the needle. If the bike is older than 06, does it have the ap mod?
If you read the article you will see the needle circuit and pilot circuit do overlap. Also find out what your fuel screw is set to. Find it on the carb, count the turns as you turn it in til it gently seats. Unsrewing it gives more fuel, tightening less, you may be able to fine tune your flat spot away with the fuel screw, but the range is 1 1/2 turn to 2 out from the seat, less than that and you should install a smaller pilot jet, and more than 2 install a larger pilot jet.
