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Selecting the right pilot jets
- toadson
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I've recently read a post on here talking about MAC headers and having to rejet. My bike has a 4 into 1 MAC header and stock airbox. The member said when he installed his MAC header, he had to install larger pilot jets. Once I read this, I started looking into the symptoms of having too small of pilot jets. On a cold start, my bike will not run without the choke being fully applied. Even on a warm day, it still needs the choke. It also does not rev smooth with a small blip of the throttle, or while gradually increasing the gas. It just sounds lean until it has fully warmed up. Once warmed up, the bike runs great. I've also cleaned these carbs multiple times and I know they are clean, so this should not be the problem.
So assuming my pilots are the problem, what would be the next best size to try? On z1enterprises, they only list #15, #20, and #22. Would #20 be too big of a jump? I've always heard of people using #17.5, but I'm not sure why Z1 doesn't list it.
79 KZ1000 LTD. Mikuni VM26 w/ accelerator pump. 4 into 1 header. Stock intake setup. GS1100 Swingarm, My swap thread: kzrider.com/index.php?option=com_kunena&...d=5&id=210872#210872
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- timebomb33
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1973 z1 2-1974z1-a,2-1975z1-b dragbikes1015cc+1393cc, 1977kz1000,1978kz1000,1981kz1000j, 1997 zx-11, 2000 z12r,1428turbo nitrous pro-mod and a shit load of parts thats all for now leader sask.,CANADA
I THINK MY POWERBAND BROKE
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- toadson
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79 KZ1000 LTD. Mikuni VM26 w/ accelerator pump. 4 into 1 header. Stock intake setup. GS1100 Swingarm, My swap thread: kzrider.com/index.php?option=com_kunena&...d=5&id=210872#210872
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- timebomb33
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1973 z1 2-1974z1-a,2-1975z1-b dragbikes1015cc+1393cc, 1977kz1000,1978kz1000,1981kz1000j, 1997 zx-11, 2000 z12r,1428turbo nitrous pro-mod and a shit load of parts thats all for now leader sask.,CANADA
I THINK MY POWERBAND BROKE
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- Patton
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...79 KZ1000 LTD...#15.0 pilot jets...ran lean...pilot jets are too small...cold start, my bike will not run without the choke being fully applied. Even on a warm day, it still needs the choke. It also does not rev smooth with a small blip of the throttle, or while gradually increasing the gas. It just sounds lean until it has fully warmed up. Once warmed up, the bike runs great....
Am thinking oem default pilot air screw position is 1.25 turns out from lightly seated.
Likely already done in this case, but if not, could enrichen pilot circuit mixture by turning IN the pilot screw 1/4 turn and test run for effect. As known, turning IN restricts volume of air reaching the pilot jet, which allows less air past the pointed tip of the screw needle.
Good Luck!
1973 Z1
KZ900 LTD
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- ccrydercu
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- timebomb33
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1973 z1 2-1974z1-a,2-1975z1-b dragbikes1015cc+1393cc, 1977kz1000,1978kz1000,1981kz1000j, 1997 zx-11, 2000 z12r,1428turbo nitrous pro-mod and a shit load of parts thats all for now leader sask.,CANADA
I THINK MY POWERBAND BROKE
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- toadson
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79 KZ1000 LTD. Mikuni VM26 w/ accelerator pump. 4 into 1 header. Stock intake setup. GS1100 Swingarm, My swap thread: kzrider.com/index.php?option=com_kunena&...d=5&id=210872#210872
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- roy-b-boy-b
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1979 LTD Street Fighter.1977 KZ1000
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- Mcdroid
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- Gone Kwackers
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Michael
Victoria, Texas
1982 GPz750
1977 KZ1000A
1978 KZ1000A
1982 GPz1100
1975 Z2A
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- toadson
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McDroid, my air pilots were set about two full turns out, but I'll have to check and see if mine will protrude into the carb throat like you mentioned. I know how it is to mess with these carbs all the time. I bet I've removed and worked on them 15-20 times since I bought the bike almost two years ago.
79 KZ1000 LTD. Mikuni VM26 w/ accelerator pump. 4 into 1 header. Stock intake setup. GS1100 Swingarm, My swap thread: kzrider.com/index.php?option=com_kunena&...d=5&id=210872#210872
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- timebomb33
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1973 z1 2-1974z1-a,2-1975z1-b dragbikes1015cc+1393cc, 1977kz1000,1978kz1000,1981kz1000j, 1997 zx-11, 2000 z12r,1428turbo nitrous pro-mod and a shit load of parts thats all for now leader sask.,CANADA
I THINK MY POWERBAND BROKE
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