KZ1000 Miss at 3800 RPM

nope...didn't fool with the carbs...but musyt have messed something up...

continuing on....checked the timing with a strobe light and the advancer is working fine. The fault tree in the KHI Manual seems to infer there is a coil issue if you have spark and the advancer is working. Any thoughts on that? Assuming this is an electrical problem also.

grumpy56 wrote:

continuing on....checked the timing with a strobe light and the advancer is working fine. The fault tree in the KHI Manual seems to infer there is a coil issue if you have spark and the advancer is working. Any thoughts on that? Assuming this is an electrical problem also.

could be a coil issue, but i dont get how it would clear up in upper rpmS....battery good? a bad coil is bad all the way through i would think..assuming shim job is good, i keep thinking fuel.....when it stumbles, what comes out exhaust?
i would guess if its a coil prob, you should be spitting a little black out the pipe...gas smell?
just trying to help...keep us posted.....

mine was a coil wire that worked free from an after-market dyna coil......but it could have been any thing i did a second then thrid visual with a wiggle the wires to look for loosey goosey's and still could not find anything.......only upon a fourth... one piece at a time elec teardown did a burned inner color(copper green) alert me... before this last time coil wire connectors has been the previous culprit a few times and only removal and reconnecting has helped find the bad spot/spots...i'm repeating info i know....just that i've had similair demons of late and now am riding again....really hope you find it bro...probably somthing simple...mine was...good luck

thank you guys...i will run one of the tests in the manual to kind of check the coils and also ensure all the wires are connected properly...the only funy thing i noticed when i changed the plug wires was all this "dust" (fried connector I think) that emptied out of the coils..don't think that is healthy, but as ketih mentions, everything coming back loud and clear when really revved is weird...will keep you guys posted

grumpy56 wrote:

thank you guys...i will run one of the tests in the manual to kind of check the coils and also ensure all the wires are connected properly...the only funy thing i noticed when i changed the plug wires was all this "dust" (fried connector I think) that emptied out of the coils..don't think that is healthy, but as ketih mentions, everything coming back loud and clear when really revved is weird...will keep you guys posted

check your battery....see what ya get across terminals with bike off, get it running and if ya can get it up to around 4k , read across batt again with headlite off....you can get a cheapy digital multi-meter...harbor freight has one for like 5 bucks...i just grabbed one to replace my sunpro that crapped out...i was using a wally mart special, but its tough to tell where ya are
with the way the numbers are set up on face...good for ballpark...keep us posted....

my recent sputter would leave when i speeded up and return at part throttle or when picking up speed from stopped to full traffic speed again....or if i pulled in the clutch and blipped the throttle it would kinda clear up ...but then it would start again under load when the clutch was out....making me think,,,,fuel starve,,,ign advance,,,,
the wire could still get a jumping spark to fire sometimes but was an inch out of the coil......yours may be somthing totaly dif but sounds like what i found to be a coil not firing right.....any lttle info the guys gave me helped..... food for thought....craig

Grumpy, may sound silly, but does your' timing light remain constant when you hit the flat? I've seen cdi type ign's which either lost spark or timing went erratic at certain rpms. Painless dio. could at least point you in a direction. Luck G Anouther silly thought, If running stock airbox, make sure intake is clear. I once had my bandit try to swallow a tank bag strap and had similar effect.

Does it do this at the same throttle position each time? If so, what throttle position is it? 0, 1/4, 1/2, 3/4, WO?

Battery might be failing or undercharged. If not already done, would assure fluid levels are correct. and charge it overnight and load test it. As known, voltage measurement alone does not assure full charge and ability to hold full charge.

Would assure clean tight terminal cable connections, and good ground connection where negative battery terminal attaches to engine/frame.

With known good fully charged battery and tight terminal connections and ground connection, as keith1 suggested, would measure voltage across battery terminals at low idle (look for 12-13 volts) and at 3000-4000 rpm (look for 14-15 volts). This will help determine condition of charging system and functioning of regulator and rectifier.

Then measure positive voltage actually reaching each coil primary winding, which should be equal to or almost same as voltage measured across battery terminals.

Good Luck!

Appreciating the help guys and here is further info/questions.

The first thing I did was to replace the battery since I knew the old one was tired. Didn't help. Also, the timing light fires as expected even when the engine is sputtering. I had the pickup on cylinder # 1. Could I use the timing gun to check for juice at my problem RPM area by attaching the pickup to each cylinder and seeing what happens?

Airbox is clear and the miss appears to be rev dependent, not throttle position, so that would lead me to think it is an electrical issue. Will measure the coils tonight and see what I get.

Boy, haven't had this much fun since I spotted some attractive honeys on the Daytona Beach back in 1976, decided to give the old Z-1 a bit of throttle, and zzzzrrrrreeeeeewwwww...Z and me on the sand! Memorable moment.

just to verify something, have you sprayed water on the ex pipes when running to see if you have a cold cyl or two,I would do this at idle and athe rpm where the stumble kicks in.