missing 1985 zn1100

zn1100 engine missing
Took bike to dealership to check engine misfire under load! mechanic syncronized carbs and raised needle to richen mid range and said it was good! I drove home got 2 miles from dealer and started missing so went home. Took back up to mechanic and now he did compression check, it was good, took carbs apart found some rust particles in carb bowl and cleaned all up put inline fuel filter in and assembled back together and said it was good to go. Called me and said it was ready for pickup so i told him be there tommorow to pick up.The next morning i was going to get it and phone rang, mechanic took bike for a spin that morning and to his surprise it started missing when he drove it. When he drove it one direction bike started to miss and when he turned around and went opposite direction it didnt miss so now he thinks its the wind causing a vacuun leak stopping fuel to carb or carbs.its still at shop gong on 2 months. Ive had carbs cleaned, carbs synchronized, replace all intake rubber boots, new needle and seats in carbs, new spark plugs, gas tank drained ,cleaned, inline fuel filter installed. Can anyone help me!!!!! thanks scott

vent clear for the fuel tank cap?

I'm not sure on that. Does this model have a vent built in fuel cap?
thanks scott

pods or airbox?
either case start looking at the ignition side.

Everything on the bike is stock. I sure would think the mechanic working on bike would check them out but not sure at this point. Bike has 17,000 miles on it. I haven't heard anything from the shop in 2 weeks. Shop started working on bike Oct.1,2010. Anymore suggestions would be greatly appreciated. thanks scott

Sounds more like the coil or ignition breaking up to me if it's only happening every couple rides like you stated Electronics are weird like that.

Is there a way that the electrical parts you are talking about can be checked to see if they are the issue. At least then that could be one less thing or things it could be causing the problem. thanks again Scott

If it were me, I'd get some "De-oxit" electrical contact cleaner/preservative and clean all ignition related conectors. This might take a day to throughly do all the connections(one at a time to avoid mixing up circuits).

www.deoxit.com is their website, and it's available at Radio Shack Stores in the U.S. and other electronic supply places. It's a pricey item($15 for a two pack) but good stuff.

I use this cleaner on my bike,home entertainment center cables, and cordless phone charging cradles.

Sounds like a loose or broken wire in the ignition system. Turning loosens/reconnects it...I would look at the wiring and connectors first.

Sounds like a play back of my GPz 750. Shop situation and all. If your the least bit mechanically inclined. retrieve your bike bro. because its just sitting there. It could sit at home with you. for no charge. My problem was an intermittent short in my starting system. went through my bike,cleaned and resoldered some connections. ran beautifully afterwards. Post your progress someone here has been through it believe me..Good luck

In addition to all the above, would assure:

Functioning automatic advancer (viewed under timing light);
Fat blue spark at plug tips;
Good battery, fully charged;
Clean snug battery terminals connections, and integrity of connection where negative battery cable attaches to rear of engine;
Measured voltage being received at ignition coil primary terminals;
Ohm check primary windings and secondary loop (Kawasaki ignition coil electrotester would be even better);
Spray water mist over coils and plug wires in dark garage with engine running (look for sparks = leaking voltage);

Valve clearances to specs;

Check float bowl fuel levels using clear tube method;
Petcock screens should be clean and clear;
Fuel should freely flow from petcock;

Assure integrity of vacuum line from carb to petcock (snug fit with no leaks or cracks).

Good Fortune!

Thanks for all of the advice given. I'm going to call shop tonite and see where that at with bike. Then i will determine whether i go pick it up and pay bill and start trouble shooting all the options i have been given from you guy's. Again i really appreciate all of your help in trying to get my bike back up and road ready! thanks Scott