How far to screw carb jets. 78 kz750
- Lwassner
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How far to screw carb jets. 78 kz750
23 Sep 2015 08:13
I have a 78 kz750 twin with stock carb and jets. I just put pod filters on and am adjusting for for fuel. I move the clip on the needle from 2nd to 3rd notch and now am trying to figure out how far to screw the two jets that unscrewed out of the inside and outside of the bowl to clean.
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- 1977-Z1-A1-LTD
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Re: How far to screw carb jets. 78 kz750
23 Sep 2015 09:59
The pods air filters allow more air flow through the carbs, and normally require bigger main jets in order to compensate for this added air flow. Need to increase main jet size to get the right air/fuel mixture and increased performance (I'm assuming that's why you installed these filters). Dynojet makes a kit complete with instructions that will help you in your mission to get better performance using these air filters. The main jet is in the bowl of the carb, your manual should have details on how to remove the bowl and the jet. If the bike was running great before you put on the pods, you might consider going back to the stock set up. Best of luck!
1977 KZ1000 LTD
1990 FXR
1998 KTM 300 EXC
1974 CBR 350
1990 FXR
1998 KTM 300 EXC
1974 CBR 350
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- timmythecop
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Re: How far to screw carb jets. 78 kz750
25 Sep 2015 19:28
If you are referring to the idle mixture screws here is how i have had good luck:
Start and idle for a while. one carb at a time, go backwards (anti clockwise) from a lightly seated adjuster. take note when the idle gets higher. dont worry if it is too high, just go back and forth until you have the most rpm. now re-adjust the idle back to around 1200rpm. do the same on other carb, until you have the fastest idle. re do the idle adjuster, and your screws are set.
for diagnosing problems, it helps to know that idle mixture screws on the airbox side regulate air and if it is on the engine side, it regulates fuel. also remember that this adjustment handles idle, an a fraction of off idle, so dont fiddle with them when there is a problem with any other rev range.
good luck
Start and idle for a while. one carb at a time, go backwards (anti clockwise) from a lightly seated adjuster. take note when the idle gets higher. dont worry if it is too high, just go back and forth until you have the most rpm. now re-adjust the idle back to around 1200rpm. do the same on other carb, until you have the fastest idle. re do the idle adjuster, and your screws are set.
for diagnosing problems, it helps to know that idle mixture screws on the airbox side regulate air and if it is on the engine side, it regulates fuel. also remember that this adjustment handles idle, an a fraction of off idle, so dont fiddle with them when there is a problem with any other rev range.
good luck
Can I convince you to paint it flat black?
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- 650ed
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Re: How far to screw carb jets. 78 kz750
26 Sep 2015 03:28
The '78 KZ750 came with CV carbs, so I suspect you have your work cut out for you. I hope you didn't toss the airbox. Ed
1977 KZ650-C1 Original Owner - Stock (with additional invisible FIAMM horn)
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- bountyhunter
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Re: How far to screw carb jets. 78 kz750
26 Sep 2015 10:27On mine they run best at 2 turns out (CCW) from all the way in. I have stock airbox.Lwassner wrote: I have a 78 kz750 twin with stock carb and jets. I just put pod filters on and am adjusting for for fuel. I move the clip on the needle from 2nd to 3rd notch and now am trying to figure out how far to screw the two jets that unscrewed out of the inside and outside of the bowl to clean.
1979 KZ-750 Twin
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- Randombeat
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Re: How far to screw carb jets. 78 kz750
26 Sep 2015 12:55
1980 kz750h, UNI pods, 3turns out... (runs great, but wasnt so great with cheapo pods)
1980 KZ750H LTD-- pods-- vance & hines 4-1 --speedo/tach/blinker/switch deletes -- brat style
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- Topper
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Re: How far to screw carb jets. 78 kz750
26 Sep 2015 13:21
I think he's asking about the jets in the bowl. You screw those all the way in until they're tight. As stated by others, stock jets aren't going to cut it with pods though.
Permanent and perpetual noob.
1979 KZ750 Twin
2009 Kawasaki Versys
1979 KZ750 Twin
2009 Kawasaki Versys
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- Randombeat
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Re: How far to screw carb jets. 78 kz750
26 Sep 2015 13:25 - 27 Sep 2015 03:51
yessir. i went from stock (125/68/35) to 140/70/38 on jetting, seated fully snug... dont be“ieve it wuld be a good idea to run jets loose, atall... i was speaking about pilot air/fuel screws.
1980 KZ750H LTD-- pods-- vance & hines 4-1 --speedo/tach/blinker/switch deletes -- brat style
Last edit: 27 Sep 2015 03:51 by Randombeat. Reason: correct slow jet to 35
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- undiablo
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Re: How far to screw carb jets. 78 kz750
26 Sep 2015 13:41
Randombeat:
Are you using slow pilot jets #38 from JetrUs? some time ago, keihins cv34 slow pilot jet where only obtainable form Kawasaki dealer and only #35.
Are you using slow pilot jets #38 from JetrUs? some time ago, keihins cv34 slow pilot jet where only obtainable form Kawasaki dealer and only #35.
Kawasaki KZ 750/4 LTD 1981
Kawasaki KLR 650 2011
Argentina - Buenos Aires
Kawasaki KLR 650 2011
Argentina - Buenos Aires
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- bountyhunter
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Re: How far to screw carb jets. 78 kz750
26 Sep 2015 23:08 - 26 Sep 2015 23:09I believe the 78 750 is essentially identical to the 79 and has BS-38 carbs. For stock aiirbox, best pilot jet size is 45 - 50 and you run the mix screws about 2 turns out. For pods? Good luck, I don't have those.Randombeat wrote: yessir. i went from stock (125/68/38) to 140/70/38 on jetting, seated fully snug... dont be“ieve it wuld be a good idea to run jets loose, atall... i was speaking about pilot air/fuel screws.
Pilot jet type is BS30-96.
1979 KZ-750 Twin
Last edit: 26 Sep 2015 23:09 by bountyhunter.
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- Randombeat
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Re: How far to screw carb jets. 78 kz750
27 Sep 2015 03:49 - 27 Sep 2015 03:50undiablo wrote: Randombeat:
Are you using slow pilot jets #38 from JetrUs? some time ago, keihins cv34 slow pilot jet where only obtainable form Kawasaki dealer and only #35.
yes, link here: jetsrus.com/a_jets_by_carburetor_type/jets_keihin_3M_slow.html
1980 KZ750H LTD-- pods-- vance & hines 4-1 --speedo/tach/blinker/switch deletes -- brat style
Last edit: 27 Sep 2015 03:50 by Randombeat.
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- kanexx
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Re: How far to screw carb jets. 78 kz750
15 Oct 2024 21:05
I have the same set up as you , i finally got it to idle great now I need to get it to run good after I let up from wot. After I let up on throttle it revs high and I will down shift and then up shift the it settles down , but every time I open up does the same thing, any ideas ? Thank you
kane
kane
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