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KZ400 Idle issues. I'm stumped.
- SWest
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- 10 22 2014
Steve
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- Patton
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www.z1enterprises.com/ItemDetails.aspx?i...00&item=16065-1002x2
Good Fortune!
1973 Z1
KZ900 LTD
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- DoctoRot
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- SWest
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Steve
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- DoctoRot
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The bike now runs as good as it ever has with the idle issue seemingly gone, although i haven't ridden it much. after a short 10 minute ride i pulled the plugs and the #2 cylinder is still rich while #1 looks perfect. I pulled the carbs off again, and meticulously compared the jets and housings. everything appears to be identical. has my spark plug cap/wire gone bad? Im still baffled by the timing as well. Could it be that the cam chain has stretched out and is no longer giving a reliable time? the bike still feels boggy in the middle/upper of the RPM range. starting at about 5500.
The good news is i have become a pro at getting the carbs on/off this bike. :ohmy:
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- DoctoRot
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- Z650Spirit
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Pablo.
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- DoctoRot
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adjusted valves,
cleaned and lubed advancer.
set point gap
set timing
new battery
cleaned carbs THROUGHLY
carbs completely rebuilt, with OEM pilot jets
new diapraghms in carbs
replaced jet needle holders with used good condition ones off ebay
carb floats set with tube
carbs synced
replaced carb holders
Air box boots are hard but appear to be in OK condition, doesn't seem to be any leaks.
New OEM air filter
compression is good 150PSI on both
tested spark plug wires - good
new spark plug caps
new spark plugs
stock exhaust with new gaskets, no leaks.
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- Z650Spirit
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www.kz400.com/Workshop%20manual%20bilder...nual%20p.150-155.pdf
Something is obviously still wrong in the rich running carb. Makes no sense though that you are able to get a blue flame through the Colortune on both carbs. I suggest you clean the plugs from carbon and test again.
Check out thoroughly that everything is there as described in the manual, jet sizes, o'rings, etc (with special attention to the o'ring and washer behind the spring in the pilot screw). and adjusted to factory specs.
Pablo.
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- DoctoRot
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Is it possible the needle is not seating right in the holder? i guess i will switch them and see what happens. It still doesn't explain the erratic idle. Im tempted to buy a used advancer off ebay and new points/condenser so i can rule that out. There is something strange going on there. Could my cam chain be stretched out? I adjusted the tensioner and there doest seem to be any particularly tight/loose spot.
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- Patton
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DoctoRot wrote: New plug caps in . . . tested spark plug wires - good
new spark plug caps. . . .
Presupposing a perfect air/fuel mixture into each combustion chamber, incomplete combustion may result from weak spark due to excessive resistance in the secondary loop.
How were the plug wires tested?
An ohm-check isn't an adequate test, and won't show leakage of high tension voltage through old hard, cracked, worn-out insulation on the wires.
Are plug wires solid core or suppression core?
What spark plugs are fitted?
Am thinking that spark plugs for the model at hand are supposed to be NGKB7ES.
And NOT "R" plugs such as NGKBR7ES.
The caps are likely resistor style caps, having built-in resistance.
If there's going to be any resistance at all in the secondary loop, it's important that resistance be in only one component, such as resistor style caps OR "R" plugs OR suppression core plug wires.
Resistance in more than one secondary loop component results in weak spark and incomplete combustion.
Could install new Dyna solid core plug wires (they come with caps already built-in) and new NGKB7ES spark plugs.
Dyna solid core plug wires are available from Z1E:
Click here > Black
Click here > Red
Good Fortune!
1973 Z1
KZ900 LTD
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- undiablo
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Best regards from Buenos Aires.
Kawasaki KZ 750/4 LTD 1981
Kawasaki KLR 650 2011
Argentina - Buenos Aires
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