Suzuki gt380 running on 2 cylinders carbs clean main jet clear could it be the coil but their seems to be a good spark

Be sure the ignition wire from the coil, the spark plug, and the plug boot are all in good working order and spark is present with the engine cold. Remove the carb that seems to be the problem. Make sure the fuel from the tank to the carb is not restricted at all, check any filters, screens, petcock valves, etc. Pull the float bowl from the bottom, remove the float ratainer pin, float assembly and shut off needle valve. Blow through the passage with compressed air to make sure it is clear of debris. Now remove the jets from the carburator body. Usually a small flat head screwdriver, and/or a 6mm-8mm wrench is needed. One is located directly under the needle jet, and the other will be close by the first. There may be 3 jets but without seeing the carb I cannot say for sure. If so, remove the third as well. Hold each jet to light to be sure it is clear of debris, used compressed air to clear the passages in the carb body. Assemble and install the carburator and run the engine. If the problem persists, find out if your engine has hydraulic lifters, if so the lifter may not function correctly until you oil warms up and is thin enough to pump through the lifter. This would keep the valve from opening or limit how far it opens, restricting the fuel from entering or exiting the cylinder correctly. Once it warms and the oil thins out the lifter would begin to work properly and the engine run normal. Some might suggest the timing but that isnt likely since the probpem isnt consistent after the engine is warmed up. This could be a sign of a failing gasket on the cylinder, since the engine cold may not pull enough from the intake to draw fuel in, then once the engine is warm, the cylinder expands closing the gap at the place where the gasket is failing, causing it to pull from the intake normally. A leak down test will answer that for you. That would be the last thing to check however. Hope this helps.

lots of reasons check spark again and fuel to what filter carb? engine problems basically are gas and spark so tells me its gas pull plug squirt some gas 2 stroke make shure its oil/gas 4 stroke gas only in cylinder use a eyedropper or a clear gas line of fuel to put fuel in cylinder put plug back in fire up if starts problem in carb if no start may have jumped timing check air filter may even have a mouse nest in it most people don't drain gas out of carbs for winter drop carb clean bowl with pure white vinegar clean all jets pilot / main reasemble

Make sure the battery is fully charged and check your charging system to make sure you are putting out 14 volts or so. If yes then check the spark plug wires for defects, then check the spark plug itself if black or wet looking then it may be from a fouled plug or weak spark. If you can switch the coils to see if that has the opposite effect.

just coz you put youre thumb over the hole and you have compression does not mean that you have good compression find out what the maximum pressure is supposed to be and get a porper compression tool.
oil from the exhaust is odd i think this could be v/v guides but it would not explain why exhaust is not getting hot.

There are several possibilities. Check for spark on the bad cylinder. Remove the spark plug then hook the plug wire to it and then ground the metal side of the plug against the cylinder head while the engine is running. Is there spark present? If not, the ignition coil is probably bad. If spark is present, your bike has CV carbs. there is a chance the diaphragm in the bad carb has a pin hole, crack or tear in it. This would prevent the slide in the center of the carb from raising. Also possible is a stuck float needle not letting gas into the carb. Another possibility is trash in the carb plugging up the main jet. Go ahead and inspect the carb and clean the carb. Please rate my answer.

Have you checked for a spark? This sounds like an ignition problem. Check your points are set correctly for that cylinder as well.

How good did you clean the carbs? The idle jets usually have small holes along the side, and if they are blocked with dirt or bad fuel, it won't idle. Make sure ALL of the passages are clear, and all jets are clear, through the center and holes in the sides of the pilot jets.

the carbs need to be cleaned out, the front carb has a stopped up low speed jet. If you have already cleaned them then they need to be synchronized. Cleaning means removal and dis-assembly, you cannot get to the jets by spraying cleaner in the air intake.

What have you done if anything to check out this problem?
Several causes could be: 1. Not getting fuel do to clogged jet in the carbs for those cylinders. 2. Fould plugs in those cylinders. 3. Not getting spark to those cylinders/bad coil 4. no compression in cylinders that don't fire.
So run the bike and determine which cylinders are not firing for sure. use a squirtgun and hit the header with some water. running cylinders with smoke the water. non running will not. Then remove and replace the plugs.(look at old ones, all oily=bad) See if they are wet and shiny but not black...Not shiny=no fuel. Tear carbs apart and clean. Check to see if you have spark leave spark plugs unintsalled from motor but installed in spark plug boot. see if they spark when you start it. Do a compression check. wet and dry. could be rings or valves.
If the bike was sitting for a while then probably clogged jets...This is where stabil comes in handy or else drain the bike at the end of the season.

First thing I would do is change the battery and spark plugs. start there.