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3 and 4 not firing???
- soccerd31
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thoughts, comments, and suggestions are appreciated!
1981 KZ750 LTD H2
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- jeffasaki
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78 Z1R
78 KZ1000
76 KH500 gone
71 HS1B 90
81 GS 1100 gone
80 PE400
02 KLR
Ontario Canada
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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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Then measure voltage reaching coils. Should ideally equate to battery voltage.
Are spark plug wires old and hard, and perhaps leaking voltage??
Good Luck!
1973 Z1
KZ900 LTD
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- Patton
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And also perform compression test.
Good Luck!
1973 Z1
KZ900 LTD
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- TeK9iNe
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The numbers should be within about 15% of eachother - cold. -less than 10% hot.
Check each of the plugs by laying them on, or holding them against head and trying to start. As mentioned, should be nice blue snappy spark for each one.
Remove carburetor rack.
dissasemble carbs 1 at a time, using a single small strand of stainless steel brush thread, push it through all of the jets and pilot passages carefully. Were not trying to enlarge the holes, just make sure they pass some fuel.
Re-assemble everything. AIR TIGHT!
Turn your idle way up to about 2000rpm.
Get the bike running, off choke, and check the header by quickly tapping each pipe to see if its getting hot.
If you rev the bike up and those cylinders start firing, then your pilot passages are still clogged.
If you turn down the idle and a cylinder (or 2) stop firing, the sync may be way off, or, the pilot circuits are still clogged some.
Turn idle up to point that all cylinders fire.
Remove the gas tank, start the bike, and then pour seafoam directly into the gas line (straight into the carbs). Rev the bike up to 4000rpm and hold it there for a minute to get the seafoam into everything.
Turn off, and let sit overnight.
Next day, just put tank back on.
It will likely run MUCH better after this and idle much lower.
Good luck, let us know!
Likely need vacuum sync afterwards...
Theres way more and other ways of going thru everything, but hey, you just want to ride the darn thing, right!
Motorcycle Shop Owner/Operator
79 Kawie Z1000 LTD
81 Kawie Z1000 CSR
83 Honda VT750C A
85 Kawie GPZ900 A2
86 Zukie GS1150 EG
93 Yamie XV1100 E
Lucky to have rolled many old bikes through my doors
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- JMKZHI
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- Patton
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Would also assure correct fuel level in float bowls via the clear tube test (bike in normal running mode with carbs fully assembled).
Because, where the float bowl fuel level is too high, even otherwise perfect carbs will run too rich. And this is true regardless of perfect compression and ignition.
Point being, the other possible suspects underlying poor combustion should be checked and cleared before addressing the carb internals. And if not done, tearing into the carbs may likely prove a futile exercise, because even perfect carbs can't compensate for deficiencies in the other systems.
So sayeth the peanut gallery. :laugh:
Good Luck!
1973 Z1
KZ900 LTD
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- YUKABODOS
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1. Spark - blue and fat? Check plugs and resistance of spark plug caps. May need to replace a bad plug and or trim spark plug wires.
2. Check the timing and the wires and connections from points/ condensors to the coils. Check all ground wires and check for oxidization. Is the advance stuck? Take the advance off and clean and lube it. Ensure timing is bang on. If required lightly file the point contacts to ensure there is no rust preventing the points contacting one another.
3. After diagnosing electrical ....and still not working...check carbs. Clean and rebuild if required.
4. Check valve clearances.
Fingers crossed that it is only a simple fix like a loose wire ect.
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- Patton
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...
3. After diagnosing electrical ....and still not working...check carbs. Clean and rebuild if required.
4. Check valve clearances....
Good points, but imo valve clearances should be checked and assured correct before addressing carbs.
Even perfect carbs can't compensate for poor combustion due to poor compression resulting from a too tight valve, especially at normal engine operating temperature.
Good Luck!
1973 Z1
KZ900 LTD
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- TeK9iNe
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YUKABODOS wrote:
...
3. After diagnosing electrical ....and still not working...check carbs. Clean and rebuild if required.
4. Check valve clearances....
Good points, but imo valve clearances should be checked and assured correct before addressing carbs.
Even perfect carbs can't compensate for poor combustion due to poor compression resulting from a too tight valve, especially at normal engine operating temperature.
Good Luck!
I have to agree. I should have said this before... :blush:
According to the manuals, this is the first item to be checked as part of regualar maintenence.
It is not very difficult to do, and re-assures you that the engine is not mimicking a carburetor problem, which so often happens.
Always perform all regular maintenence before tackling other problems, it really elliminates alot.
Motorcycle Shop Owner/Operator
79 Kawie Z1000 LTD
81 Kawie Z1000 CSR
83 Honda VT750C A
85 Kawie GPZ900 A2
86 Zukie GS1150 EG
93 Yamie XV1100 E
Lucky to have rolled many old bikes through my doors
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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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