Idle tunning

  • Carmstr1
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Idle tunning

10 Jan 2015 04:21
#658238
I've been building my first Kz and im having a problem with my idle after cleaning the carbs I've adjusted my idle screws and they seem to be insyc but it won't idle down does anyone have any ideas the carbs are either a 29mm or 28mm mikuni
This is my first inline bike I've built I've always tinkered with vtwins and my first forum
Thanks

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  • KZJOE900
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Re: Idle tunning

10 Jan 2015 05:06
#658239
There are some possibilities which you will need to narrow down by testing an elemination. First, please post your model and year. Should post that in your signature. Please indicate how the bike ran prior to cleaning if it did at all.

Could be any of the following:

Carburetor still not clean.

Air leak in the intake boots (cracked or not seated properly)

Carburetors out of balance.

Problem with the enrichment circuit.

Leaky shaft seals.

Just throwing these out there for you to consider. Good luck.
Current project 76 KZ900 (This was a Vetter model)
76 KZ900
81 XJ550H SECA (Current Project)
82 XJ550R SECA
Past:
86 FJ1200
74 Z1900
72 CB450

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  • Carmstr1
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Re: Idle tunning

10 Jan 2015 05:23
#658242
Well this bike is truly a Frankenstein lol it's a 1984 kz1000 frame it has a 1982 Kz 1098cc j engine and pre 1980 carbs and 1999 Cbr 1000 rims and breaks and a R1 front end (not sure of the year ) the boots on the carbs are brand new and the carbs looked really clean when I reassembled them I was curious if there are some vacuum lines that I don't know of on 28mm or 29mm mikuni and by balance what do u mean ?

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  • TexasKZ
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Re: Idle tunning

10 Jan 2015 05:42
#658244
Typically, there is one vacuum port on each carb. One should be connected to the vacuum port on the fuel petcock, one should be connected to the anti-polution equipment if it is present, and the other two should be capped off. These ports are also used to balance, or synchronize, the carbs. This is done using a tool that measures the vacuum at each port simultaneously. The goal is to have each one pulling the same vacuum. The carbs also must be providing the same, correct air/fuel ratio. This is adjusted by jet size, needle size and position, fuel level in the float bowl (not float height) and the idle mixture screw. There are some good tutorials on this in the filebase.
1982 KZ1000 LTD parts donor
1981 KZ1000 LTD awaiting resurrection
2000 ZRX1100 not ridden enough

www.kzrider.com/11-projects/620336-anoth...uild-thread?start=24

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  • SWest
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Re: Idle tunning

10 Jan 2015 05:59
#658246
Carmstr1 wrote: I've been building my first Kz and im having a problem with my idle after cleaning the carbs I've adjusted my idle screws and they seem to be insyc but it won't idle down does anyone have any ideas the carbs are either a 29mm or 28mm mikuni
This is my first inline bike I've built I've always tinkered with vtwins and my first forum
Thanks[/quote

The 29 and 28's look completely different. The throttle shaft is in front of the 29 carb and in back of the 28. The idle screw is in a different place too. It's the one with the big dial, that sets your idle. You lower it, adjust your mixture screws to the highest RPM, lower it again, adjust until there is no difference achieved. You should wait ten seconds each time you make the adjustment of the mixture screws so the circuit can catch up. Mikuni International has a page on this procedure.
Steve
Z1b1000 1975 Z1b
kzrider.com/forum/11-projects/598262-kz-...-will-it-live#672882
kzrider.com/forum/2-engine/597654-poser?start=240#704229

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Re: Idle tunning

10 Jan 2015 06:02
#658247
Thank yall so much I'll check those out

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  • 650ed
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Re: Idle tunning

10 Jan 2015 08:56
#658275
One other possibility - if you disassembled the carbs. When you reassembled them did you have the main idle adjustment screw near the center of its range? If it was not, it may not be allowing you enough adjustment to bring the idle down. If that is the case you don't need to disassemble the carbs to correct it. You need to center the main idle adjuster and then lower each of the carb slides an equal amount until the idle is close to normal. After doing that just sync the carbs and you should be able to use the idle adjustment knob to fine tune the idle speed. Ed
1977 KZ650-C1 Original Owner - Stock (with additional invisible FIAMM horn)

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  • Carmstr1
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Re: Idle tunning

11 Jan 2015 06:31
#658398
Thank u 650ed that sounds like it will work cause I never messed with the idle setting when reassembling the carbs and its was all the way out when I tried to tune it the other day I'll give that a shot

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