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OK so I got this bike recently, had to repair some vacuum leaks and change points to get it running right. Now after about 150 miles on the bike I was out on a ride today, bike ran great for the first hour of the ride, then we parked at a gas station to take a break and get waters, and when I restarted the bike it ran terrible, backfiring horribly, no power etc. Well I revved it out and cleared it out and it seemed to run good again for the next hour of the ride. We got into some hilly terrain and it started bucking and popping under load, higher gear with more throttle. The problem kept getting worse until I couldn't get any power at all. Felt like it ran out of gas but I had 3/4 of a tank. Switching to reserve made no difference. So on the side of the road I made a very crude points adjustment and was able to get the bike running decently enough to get home. Now I realize moving the points messed with the timing so I reset the points, and timing and the bike seems to run OK but still has random misses and the pipes load up and backfire. I also noticed that the 2-3 points were arcing pretty good while the 1-4 were not. The 2-3 coil is new and the points and condensor are brand new. Seems to me the arcing is prematurely wearing my points down. What gives here. I'm pretty frustrated now. Bike ran wonderful until we shut it off to take a break then just didn't. Felt terrible my buddies were walking the dog all day waiting for me.. ideas?

If you can get the spark plug wires to reach you may want to try swapping the coils so the 2-3 coil now controls plugs 1&4, and vise versa. If doing that causes the problem to move to the 1-4 side the coil may be the problem. Do you know for sure that the new coil is the proper type (ohm -wise) for the bike? Ed

It came with it. It looks brand new. Not sure if the ohms are right.. What should it be? Bike is hot I'm gonna let it cool and try swapping coils and check the ohms tomorrow

According to the Kawasaki Services Manual - measured when cold the primary winding resistance should be 3.2-4.8 ohms; secondary should be 10.4-15.6K ohms. Ed

OK thanks ill check it tomorrow!

When was the last time the valves were adjusted? When they get hot the clearance goes away or lack of gets worse.
Steve

I know it's not the valves. 21k miles on the bike. I just checked them and put valve cover gasket on. After it pooped out on the ride i halfassed adjusted the points with a matchbook cover on the side of the road and it rode home ok, timing off a bit but ok. It runs perfect again now that I readjusted the points with a dwell meter and timing light. But one of them cyl 2-3 is arcing bad, and shouldn't be because the p&c are brand new just put them on last week. What I think is happening is maybe a bad coil or something that is causing the points to wear prematurely. It seems like even when it's running good the 2-3 coil is dropping out intermittently at idle because it has a random miss and the timing light skips. With 1-4 its dead even. The 2-3 coil was replaced by the po, but I think 650ed is onto something because the po was my brother in law and he has no clue how to fix bikes and probably just bought any old coil. Gonna ohm them out after work today and see. If the coil is the wrong resistance its my understanding that the points will wear fast

OK here's where I got. Cold coils #1-4 primary resistance is 4.8ohm and 2-3 (new coil) is 4.5. Can't get any secondary resistance readings off either. Started and ran bike. Ran good again till it got hot. Started acting up again. misfiring and popping. Switched coils and no apparent change. But I did notice that the old coil is now barely hitting. Put a screwdriver in the cyl 3 plug boot and held to ground with it running (on 1 and 4) and got very intermitant to no spark. Measured primary's on the hot coils. New coil measures 5.0 ohms old one (weak one) measures 5.8 and irregardless of the coil position the 2-3 point arcs a hell of a lot more than the other. All plugs are clean except #2 which looks fuel fouled but that could be from mile long rich ride home yesterday. With lots of misfiring and what have you. The fact that the older coil dropped completely out when hot tips me that that coil is poop but I'm still worried about the arcing in the points and not being able to get any kind of secondary ohm readings here. Want to make sure if i put a new coil in its not going to fry. Or am I just being overly cautious? Gonna try and post a vid of the arcing

Since #2 plugs seems to be wet with fuel here's something you may want to consider. Your bike probably has a vacuum petcock. Assuming it does, there is a vacuum line that runs from the petcock to a nipple on the #2 carb. The diaphragm inside the vacuum petcock sometimes fails. When this happens, fuel can sometimes be drawn through the vacuum line into the #2 carb and cause a rich or flooding condition on that cylinder. You may want to disconnect the vacuum line and see if it has any fuel in it - it should not. Another thing you can try is to cap off the vacuum nipple on the #2 carb and cap off the vacuum port on the petcock. Then with a clean or new #2 spark plug and the petcock on Prime go for a ride and then see if the #2 plug becomes wet with fuel. Assuming it does not, a leaky petcock diaphragm is very likely creating a problem. Ed

Yea that was my first assumption when I got the bike. Its been capped off and run in prime and no change. Besides the plug isn't wet. Its just carboned from misfiring

It does fire until the bike gets hot then only works partially at idle and part throttle then under load and high rpm it shuts off completely