ZN1100 running poorly

OK guys so I am finally getting around to my bobber project. I jetted it at 130 for the outside cyls and 132.5 for the inside ones, to compensate for the pod filters and 4-1 exhaust, altho this is just an initial starting point. My main problem is it is really hard to start and it runs like it has very little power. Lots of backfiring, 1+2 backfire into the carbs, and 3+4 exhaust pipes get EXTREMELY hot. Not hot enough to make them glow, but after about 20 seconds of operation they max out my infrared thermometer at over 400deg. OK, so something is hinky here.

Does it sound to you guys like my valves are out of adjustment, or is this a timing issue? No unusual engine noise noted, valves are opening and closing on all four cylinders. I want to wait until my repair manual arrives to open up the engine, but any advice to get me thinking in the right place would be helpful. Also, does anyone have the valve clearance data for this bike?

Thanks

"Lots of backfiring, 1+2 backfire into the carbs,"...

You sure you have the correct coil to sparky wiring?
or ignition plate wiring to coils not right...

Old Man Rock wrote:

"Lots of backfiring, 1+2 backfire into the carbs,"...

You sure you have the correct coil to sparky wiring?
or ignition plate wiring to coils not right...

Pretty sure, no book yet but 1+4 and 2+3 are sparked by the same coil, as is my Yamaha. I got this bike with almost no information about the previous maintenance. Is it possible to have switched the ignition-to-coil wires? Would it even run at all if every spark plug was firing incorrectly?

The fact that 1+2 and 3+4 are each experiencing different sets of symptoms leads me to think away from electrical problems, since 1+4 and 2+3 are wired together. Anyone else know differently?

Is there any reason you didn't jet all 4 carbs at the same setting? Why different jets in the outside cyl's vs the inside ones?

oldkaws4ever wrote:

Is there any reason you didn't jet all 4 carbs at the same setting? Why different jets in the outside cyl's vs the inside ones?

i understand his thinking on the different jetting, but i would nt do it.....a motor with good compression all the way across doesnt need creative jetting on a street bike....
as far as his problem, i would verify compression, make sure the battery is good and charging system is up to snuff....valve adj and jet all 4 carbs alike wont hurt...check timing also......are we talking bs34's?

keith1 wrote:

oldkaws4ever wrote:

Is there any reason you didn't jet all 4 carbs at the same setting? Why different jets in the outside cyl's vs the inside ones?

i understand his thinking on the different jetting, but i would nt do it.....a motor with good compression all the way across doesnt need creative jetting on a street bike....
as far as his problem, i would verify compression, make sure the battery is good and charging system is up to snuff....valve adj and jet all 4 carbs alike wont hurt...check timing also......are we talking bs34's?

Yeah I am pretty sure, they were carbs I bought from a kz1000 from a member of this site, arrived in excellent condition but I went thru them anyways. On older bikes whenever I jet for pods and exhaust, I will sometimes start out especially on bikes that are air cooled with slightly larger on the inside two, just because those cylinders run hotter and dont cool as well as the outside ones. Sometimes I switch back to all the same size depending on how it performs. Besides, this is just a starting point, once I confirm the valves and get it at least running evenly, I am going to fine tune the jetting.

The main jets dont matter right now, unless your holding the throttle wide open to get it to idle

If the bike runs/idles at all then it isnt crossed wires.

Deffinately check the timing as suggested, both 1-4 and 2-3 sides.

The 2-3 pipes are getting super hot because they are firing, but they are not receiving a properly proportioned air/fuel mixture, or the timing is way off via ignition, not likely valve timing if other cyls are fine.

What carbs? What pilot jets? What mixture screw settings? Were the throttle bodies/slides balance/same height?

Need more info...

Actually, problem solved. It was a really simple/stupid repair. The PO had taken a can of high temp black spray to this entire bike, spraying pretty much everything that he could. The spark wires were originally yellow, but he painted over them in kind of a confusing way, so that two of the wires started off yellow down by the spark plug, but ended up black at the coil. The other two wires started off black at the plug and yellow at the coil. I foolishly traced the wires based on their colors, which allowed me to miss the mistake that indeed, numbers 2 and 3 plug were switched, which is why the bike was backfiring into the carbs at 2, and the 3 exhaust was getting hot. Now in their correct placement, this bike idles great and has a TON of power. Thanks for the suggestions, the new year will find me tinkering with carb slide shims and jet sizes. Take care all.

1 coil for 2-3, 1 coil for 1-4. The spark jumps from the coil through both plug wires/plugs to meet together on ground (engine case). If either plug/wire/etc is not grounded, no spark will occur at either plug. The plugs fire on both the fire stroke, and the exhaust stroke.

Swapping plugs or plug wires for 2-3 cylinder makes no difference unless there is a damaged plug, plug wire, plug wire cap/resistor. Then the problem would just move to the other cylinder.

Me thinks you have other problems...

OK yeah you're right, I just ran outside in my pajamas to confirm, yes 1 & 4 are wired together, and 2 & 3 are wired together, just like all the other inline 4 bikes I have in my driveway. Bike still purrs like a kitten, revs high and is wicked fast. Exhaust pipes all get within 10 degrees of each other while warming up. I think the previous owner had 1 & 3 wired and 2 & 4 wired, and I changed the wires on 2 with the wire on 1, thus setting everything right. Hes got me all mixed up thanks to this ridiculous paint and I dont know what Im talking about. Yeah Im pretty sure I have it all sorted out. Thanks for the doublecheck.

Careful application of Lacquer thinner might get the PO's "Custom Paint" removed from the wiring.

Maybe a handful of cottom swabs and rags will get the black paint removed.

Thanks for the tip, I think its time for me to replace those wires anyways. This bike needs a number of crappy parts replaced before it can be deemed reliable, I'm just happy that it is running finally.