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Sudden change to terrible performance
- ottothecow
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Started up sunday morning reasonably well, rode on the freeway a bit followed by a stop for an hour, some more freeway, and then some stop-and-go city traffic to my office. It seemed great for this time as well. I went into the office for an hour, came out, and the bike was acting horribly. Had a rougher idle, wanted some choke and has no power on the low end. You can feel it kick into gear at maybe 3.5/4k and it has power although it doesn't necessarily sound good. Getting her moving from a stop though requires me to pump the clutch and try to keep the revs up (but it doesn't really like it until full throttle. Lots of back firing and if I put my hand on the carbs, I can feel it backfiring back into them (which can't be good). It just bogs down really bad at low RPM and then you can feel it all of the sudden pick back up past a certain RPM On the road back home going about 50, I couldn't really get any acceleration in 5th or 6th gear.
I noticed it was a little low on gas and switched to reserve which didn't make it better...put in 2.9gal (how big is the tank? my last fill was more like 3.1) and switched back to normal and still no improvement.
It still idles ok without choke and I tried spraying wd40 at the carb holders and air intake boots and didn't see any change in idle.
What do I need to check next? it literally sat for an hour after working great and went bad.
1979 KZ400
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- P21
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made a BIG change in my bike starts right up no stumble
just an shot
Kawasaki KZ 1000 Police (2002) P21
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- Motor Head
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- FIX UP YOUR BIKE RIGHT AND CHEAP
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1982 KZ1000LTD K2 Vance & Hines 4-1 ACCEL COILS Added Vetter fairing & Bags. FOX Racing rear Shocks, Braced Swing-arm, Fork Brace, Progressive Fork Springs RT Gold Emulators, APE Valve Springs, 1166 Big Bore kit, RS34's, GPZ cams.
1980 KZ550LTD C1 Stock SOLD Miss it
1979 MAZDA RX7 in the works, 13B...
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- ottothecow
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Here's a video I recorded of the sound the bike is making on a short ride (it had already been running for a little bit, this wasn't a fresh cold start.
I start moving at about 0:10 and you can hear the engine finally open up at about 0:20. There are several more starts and stops before I shut it off at around 3:50.
Can you tell anything from the sound it makes?
1979 KZ400
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- Motor Head
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- FIX UP YOUR BIKE RIGHT AND CHEAP
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1982 KZ1000LTD K2 Vance & Hines 4-1 ACCEL COILS Added Vetter fairing & Bags. FOX Racing rear Shocks, Braced Swing-arm, Fork Brace, Progressive Fork Springs RT Gold Emulators, APE Valve Springs, 1166 Big Bore kit, RS34's, GPZ cams.
1980 KZ550LTD C1 Stock SOLD Miss it
1979 MAZDA RX7 in the works, 13B...
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- MFolks
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1982 GPZ1100 B2
General Dynamics/Convair 1983-1993
GLCM BGM-109 Tomahawk, AGM-129A Advanced Cruise Missile (ACM)
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- Motor Head
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- FIX UP YOUR BIKE RIGHT AND CHEAP
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www.z1enterprises.com/Ignition-Kit--Kawasaki-KZ400-4477.aspx
1982 KZ1000LTD K2 Vance & Hines 4-1 ACCEL COILS Added Vetter fairing & Bags. FOX Racing rear Shocks, Braced Swing-arm, Fork Brace, Progressive Fork Springs RT Gold Emulators, APE Valve Springs, 1166 Big Bore kit, RS34's, GPZ cams.
1980 KZ550LTD C1 Stock SOLD Miss it
1979 MAZDA RX7 in the works, 13B...
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- bountyhunter
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Mine used to do that when there was crap in the tank that would work it's way down and plug a jet:ottothecow wrote:
Started up sunday morning reasonably well, rode on the freeway a bit followed by a stop for an hour, some more freeway, and then some stop-and-go city traffic to my office. It seemed great for this time as well. I went into the office for an hour, came out, and the bike was acting horribly. Had a rougher idle, wanted some choke and has no power on the low end.
Fuel system clean?
Good inline fuel filters in place?
1979 KZ-750 Twin
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- Old Man Rock
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Almost sounds as though someone jacked with your KZ...
Might want to check/verfiy there isn't something stuck down the exhaust pipe blocking flow.
First thought outside of gunked carbs came to mind is the points with emphasis on the condenser (ignition).
Check plug wires/plug caps.
1976 KZ900-A4
MTC 1075cc.
Camshafts: Kawi GPZ-1100 .375 lift
Head: P&P via Larry Cavanaugh
ZX636 suspension
MIKUNI, RS-34'S...
Kerker 4-1, 1.5" comp baffle.
Dyna-S E.I.
Earls 10 row Oil Cooler
Acewell 2802 Series Speedo/Tach
Innovate LC1 Wideband 02 AFR meter
Phoenix, Az
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- ottothecow
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I don't think the points are very old (from the spare/old parts I got with the bike, it looks like they were replaced) but I have no idea what the gap and dwell look like.
Tank looks visibly clean but I haven't taken out the petcock and I don't have an inline fuel filter (any suggestion on one to buy if I should have one?).
I am thinking this is probably something stuck in one of the carbs...but it wouldn't be a bad idea to become familiar with these other things while I try to fix it.
1979 KZ400
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