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FOULING ONE SPARK PLUG
- bgulsvig
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I idles fine but starts to cut out and stumble when given throttle. Last night I put two new plugs in and let it run (idleing and revving the engine) for about ten minutes. I removed the spark plugs to find the left side plug completely fouled with black soot. The right side was just starting to turn the electrode white. Is this a carb or ignition problem?...also there was much more pressure (exhaust) coming out the left side muffler.....thanks...
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- otakar
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74 Z1-A stock
76 KZ-900 Totaly stock vice MAC pipe
77 KZ-1000A stock
78 Z1-R 100%MINT 500 original Mi.
78 Z1-R Yoshi 1103 kit stage 1 cams Yoshi pipe. Etc
79 KZ-1300 (1400)
80 KZ-1300
81 Scratch built GPz1150R
82 KZ1000
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- TexasKZ
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1982 KZ1000 LTD parts donor
1981 KZ1000 LTD awaiting resurrection
2000 ZRX1100 not ridden enough
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- bgulsvig
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- bountyhunter
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Definitely not normal, there is something very wrong with a carb that does that. Pilot circuit could be hosed up or maybe the choke circuit is putting in enough gas and the bike is running off that?I was tinkering with it last night and tried to adjust the carbs. I let it idle for a full ten minutes. During that time I tried different settings of the pilot screws. At one point I had them both screwed all the way in and seated. There was no change in idle speed. Is this normal? I tried one, two, even three turns out with no change in RPM'S. Would this suggest the pilot passage problem? I again pulled the plugs and found one normal and one completely black
You should first set the fuel levels using clear tube.
The BS-38 carbs on the B models have the jets in the bowl. Drop the bowls (take out the drain screws) and soak them in cleaner and spray them out. If not done' drain and rinse the gas tank. Clean petcock and install filters in gas lines.
BTW: the pilot screws set at about 2 full turns out from bottomed for first adjustment on mine.
1979 KZ-750 Twin
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- TeK9iNe
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bgulsvig wrote:
Definitely not normal, there is something very wrong with a carb that does that. Pilot circuit could be hosed up or maybe the choke circuit is putting in enough gas and the bike is running off that?I was tinkering with it last night and tried to adjust the carbs. I let it idle for a full ten minutes. During that time I tried different settings of the pilot screws. At one point I had them both screwed all the way in and seated. There was no change in idle speed. Is this normal? I tried one, two, even three turns out with no change in RPM'S. Would this suggest the pilot passage problem? I again pulled the plugs and found one normal and one completely black
You should first set the fuel levels using clear tube.
The BS-38 carbs on the B models have the jets in the bowl. Drop the bowls (take out the drain screws) and soak them in cleaner and spray them out. If not done' drain and rinse the gas tank. Clean petcock and install filters in gas lines.
BTW: the pilot screws set at about 2 full turns out from bottomed for first adjustment on mine.
+1
Its not ignition related problem. If spark was weak on #1 plug it would cause identicle issues in the other #4 plug as spark travels through both plugs. If a connection problem exists it shows up on both plugs/cylinders/headerpipes.
Good Luck!
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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