stalling at 3500 R P M S

1977 K Z 1000 A-1 stock 4200 miles has been inactive for the past five years. Had to clean and adjust carbs to factory settings,also tank had to be coated inside. Ran good for 50 miles then started to break up at 3500 to 4000 rpms now stalls out at 35 to 4000 rpms upgrated to DYNA-S electronic ignition but still the same, any info appreciated.

is mechanical advance working?

yes the timing marks move to the proper position when the engine is taken to 2450 rpm.

Sounds like the carbs are running out of gas or the coils may be shorting.

Is there a fuel filter on the line to the carbs? It's possible there is some crud in the gas from the station or from the inside of the tank that could contaminate the carbs.

First thing I would do is drain each carb and capture the drained gas in a bottle to see what come out. After you drain the bowl, turn the gas on for a few seconds to drain more crud out of the bowl.

Do this for each carb and see what comes out. If you have some water, rust, dirt or other crud, it may have come out and solved the problem.

A fuel filter is a required for motorcycles!

Is there a fuel filter on the line to the carbs? It's possible there is some crud in the gas from the station or from the inside of the tank that could contaminate the carbs.

First thing I would do is drain each carb and capture the drained gas in a bottle to see what come out. After you drain the bowl, turn the gas on for a few seconds to drain more crud out of the bowl.

Do this for each carb and see what comes out. If you have some water, rust, dirt or other crud, it may have come out and solved the problem.

A fuel filter is a required for motorcycles!

O K YES I had fuel filters on the carbs I did drain the bowles the fuel came out clear then turned a milky yellow let it sit overnite and it cleared up but a lot of setiment on bottom,so then I took the carbs off again and cleaned them all the jets ect. reassembled got new gas and it fired right up,synced the carbs and got the fuel bowles adjusted and off I went, same problem,I even disconnected the filter same good flow with or without the filter.

How do you check to see if the coils are shorting ?

I was in a hurry when I made my initial response. I would change the fuel filter. A clogged filter will not flow sufficient gas when the engine is under load. It will seem like it flows fine when the bike isn't running and the hose is disconnected to check. I would look for kinks in the gas line. Last, I would remove the petcock and ensure the screen is clear.

It could be electrical. Coils shorting are generally caused by cracks in the coils. Take them off and look for cracks; especially where the mounting bars are located but also across the entire body. The cracks allow the wrappings to be exposed and if there is any dampness in the air, the coils can short. I have a set of badly cracked Dyna coils that behave exactly as you describe but fixed them with epoxy.

I would also clean out the plug caps and dab them with dielectic grease (autoparts store). You may be getting a bit of shorting in the plug caps. I am wondering if the engine is missing, or surging... etc. This might provide some clues...

Try describing the symptoms as carefully as you can.

Hi Wired, I removed the coiles and there was a wax type substance leaking from the ends, one coil was loose,that one was leaking a lot more than the other one. I cleaned them up reinstalled them and still having the same problem. After I reach 3500 R P M's and it stalls it really runs rough sputters and stalls, the only way to keep it running is to use 1/2 choke to get it back home.I wait around 5 minutes and it will start right up idle good. It will not stall at 3500 unless it is under load.Also when i'm trying to get is home I get a accumilation of gas in my exhaust which leaks out of the pipes where it connects to muffler also new plugs get sooty.Any thoughts on the leaking coiles?? I plan on rebuilding the carbs, good or bad choice?

Rebuilding the carbs is probably the wrong way to resolve this problem because it probably won't... brown stuff coming out the coils is NOT GOOD. The brown stuff is most likely the plastic insulation that coats the windings. I suspect it is melted and shorting which causes more heat so the problem will only get worse. You can measure the primary and secondary impedence to see if the coils are in spec. I don't recall what type coils you have (or what bike) but the coils should be somewhere between 1.5 and 4 Ohms primary impedence depending on the model where 1.5 Ohms is found with some electonic ignitions and 4 Ohms with points/other electronic ignitions. The secondary impedence should be 13K-18K or at least in that range. Both coils should be more or less the same. Primary is measured by putting multimeter probes (in lowest Ohms scale) on the two lugs where the power and ignition wire connect to the coil. Do this with the bike OFF. The secondary impedence should be measured by touching probes to the plug wire ends OR better, where the plug wires screw into the coils. You should be in 20K Ohms scale. These are good tests that will indicate a short if the values are outside what I noted.

The gas you are finding in your pipes is from NON COMBUSTION. When you run on two cylinders (or 3), the non-firing cylinders are still drawing gas. This isn't burned and ends up in your pipes AND IN YOUR ENGINE OIL. You had best change your oil.

Fix the coils. Once they are fixed, you are in a better position to evalutate, what, if anything, needs to be done to make the bike run right.

You can get used coils (good luck) on Ebay or buy new ones from Z1 Enterprises ( www.z1enterprises.com ). I wouldn't mess with the carbs - sounds like your coils are shot.