Only running on 2 cylinders

I have a 77 kz650, it was running great when i got it. Now its not running right. It has 4-1 exhaust, and accel coils and wires. The problem is, it is only wanting to run on cylinders 1 and 4. Its not the coils, ive tested them, and switched them around, and it still doesnt run right. Ive pulled the carbs of many times, and cleaned them, and blown them out with air. It has the dyna ignition, so i switched it back to points. When it is running, cylilders 2 and 3 both have spark. So im not sure why it is running bad. What else could it be? Cam timing? If so how do i check it? Please post any help. or questions.

are you saying when u switched coils 2 and 3 still went hot ??? check condenser and/or points/timing on 2 and 3 and related wiring

If you're getting spark on 2 and 3 when it's running, you maust have no compression, which could be from the rings or valves, or you have no fuel from those 2 carbs. the easiest thing to check right now is compression. check it on all four cylinders. Let us know it you need help with that, and post your test results. We'll go from there.

Ignition timing or cam timing, the odds of losing compression on 2 and 3 at the same time are unlikely, they do both however fire on the same stroke cycle

All cylinders fire a few degrees before top dead center on the compression stroke. However cylinders 2 & 3 are never on the same stroke. When cylinder #3 is firing cylinder #2 is on just finishing the exhaust stroke.

I'd check the valve adjustment and the compression then I'd go back to the ignition as these two cylinders share a coil.

Bill

KZCSI wrote:

All cylinders fire a few degrees before top dead center on the compression stroke. However cylinders 2 & 3 are never on the same stroke. When cylinder #3 is firing cylinder #2 is on just finishing the exhaust stroke.

I'd check the valve adjustment and the compression then I'd go back to the ignition as these two cylinders share a coil.

Bill

". Its not the coils, ive tested them, and switched them around, and it still doesnt run right. Ive pulled the carbs of many times, and cleaned them, and blown them out with air. It has the dyna ignition, so i switched it back to points. When it is running, cylilders 2 and 3 both have spark."

FROM ORIGINAL POST

yes they are not on the same stroke but same stroke cycle, i.e pistons moving at the same time, wasted spark system and all that
ur FSM should have cam timing and valve procedures
u switched back to points, recheck timing on 2 and 3 and points gap and condenser as previously mentioned FIRST then proceed

also when changing from dyna back to points I THINK the coils are different as well

When i switched the coils, i also switched the wiring around from the points.

I thought it was cylinders 1-4 fire at the same time, and 2-3 fire at the same time. I am correct right?

As for the carbs, i am 99% sure they are fine. I hae pulled them off and cleaned them probably 6 times, and there was never any sort of blockages.

I am thinking it is something with valve timing or valve clearances.

anyone know what the timing marks for the cams are, so i can check?

Dylansword wrote:

When i switched the coils, i also switched the wiring around from the points.

I thought it was cylinders 1-4 fire at the same time, and 2-3 fire at the same time. I am correct right?

As for the carbs, i am 99% sure they are fine. I hae pulled them off and cleaned them probably 6 times, and there was never any sort of blockages.

I am thinking it is something with valve timing or valve clearances.

anyone know what the timing marks for the cams are, so i can check?

should be in ur manual
look its simple
if u got STRONG ENOUGH spark and fuel and compression (which u had before) either the spark is firing incorrectly before of after (ignition timing) or the valves arent closing on time with ignition (which would mean not enough compression in cylinder) IMO
your right sort of on the spark 1&4 ,2&3
research wasted spark system, will give u a better explanation
i got got a manual somewhere on my other hard drive if u dont have one let me know,

Timing marks on the end of the cam sprocket, I think. Probably not cam timing if cyl. 1 and 4 run properly. Timing affects the whole system whether it's ignition or valve train. 2 and 3 can't be out of time if 1 and 4 are in time unless something is broken. If your valve clearances are a big enough problem for you not to run, that will show up as low compression. If you have good compression on all cylinders and your basic timing is right, that suggests you still have an ignition problem.

jjdwoodman wrote:

Timing marks on the end of the cam sprocket, I think. Probably not cam timing if cyl. 1 and 4 run properly. Timing affects the whole system whether it's ignition or valve train. 2 and 3 can't be out of time if 1 and 4 are in time unless something is broken. If your valve clearances are a big enough problem for you not to run, that will show up as low compression. If you have good compression on all cylinders and your basic timing is right, that suggests you still have an ignition problem.

thats my guess

well, Now im rele confused, I just pulled the valve cover, and the valve clearances are correct, the cam timing seems correct. So i pulled the carbs again, and checked the rubber things the carbs go into. and they were all tight, and not cracked. Im totally stumped. Could a bad condenser cause this?

Now it is trying to start, but wont.

Lets start from square one. Whats the first thing i should check?

points gap, timing plate are they correct ??? check both sides 1 and 4, 2 and 3 as per manual, coils working properly ??? spark on all cylinders ??, to check for fuel delivery issue, spray starter fluid in air filters to see if it kicks

condenser could be bad, they're cheap and its good to have extras

did u change coils when u changed back to points ??/
I seem to remember on my non metric bike that when this change was made it required different coils due to different ohms, that could likely be true in this case as well, its worth checking

one thing for sure, CHECK ONE THING AT A TIME dont do two things and try to start it, with electrical u must be meticulous