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mblackwell
02-20-2009, 01:41 PM
Please Help! I am having drivability problems with my 86 zl600. Sometimes it will cut out and back in on some (I think two of the cylinders). This happens very intermittently. It cuts all the way out as if it’s killed two cylinders and is running on only two. Then it kicks back in abruptly and will run smoothly for several seconds. It repeats this several times and sometimes backfires in the muffler as if gas is cooking off. Last fall it would clear up then cut out at about 10-13 minutes into the ride. Once it cleared up the miss usually never came back during that ride 50-70 miles. I had the carbs rebuilt but it didn’t go away. There seemed to be a lack of spark (verified (maybe) by timing light) but it wasn’t very definite and I couldn’t check it when it usually happens. I have confidence in the carb guy and think the carbs are like new. Because I thought there was a lack a spark I replaced the coils with used ones (they all checked ok for resistance). I replaced the left one before Christmas and it ran great through January with no problems until last weekend when the same miss/cut out came back exactly like before. Replaced the other coil and no change. It also seems to occur after I sit at a long traffic light and start to pull out. It has new plugs and the gas tank was acid cleaned and coated and the petcock and all the fuel lines replaced with new parts. I also blocked and capped off the suction valve and the ports on the carbs. I drove it again today in the cold and no problems on the 10 mile trip to work. Could it be something with cold weather? It ran great in January when it was cold but It was warmer the last weekend when it cut up again. . Any ideas? And any ideas to do the diagnostics. Thanks<?xml:namespace prefix = o ns = "urn:schemas-microsoft-com:office:office" /><o:p></o:p>

CHRIS
02-20-2009, 01:52 PM
have you checked the sparkplug wires ?

zlMark
02-20-2009, 03:07 PM
Welcome mblackwell!

Spark plug wires, and spark plug resister caps. If one wire or cap is bad then it will affect 2 cylinders. Also check the primary side wiring and connector and ground!

mblackwell
02-20-2009, 07:59 PM
An added note. I drove to work today and the zl sat outside in the cold (for Tennessee that was a high of 40). When I started it to go home I notced that while it was choked and warming up there was a slight miss which I would'nt have noticed except that the neutral light went out very briefly and the tach droped toward zero. After I listened closely to it I could hear a slight backfire in the mufflers like the ones before only very faint. There is something interfering with the ignition that is affected by temperature? Another flawless ride home. I love this bike. MB

kawboy
02-20-2009, 09:02 PM
. . .the neutral light went out very briefly and the tach droped toward zero.

On a 900/1000 I would say that could a junction box (aka fuse box) problem.

Don't know if the 600 is the same, but if so, try tapping on the box when the problem occurs.

The fix is to clean up the board in the j-box and reflow the solder on all the joints.