Misfire

Hello everyone a couple days ago I was riding my xj750r seca in the rain and it began to stumble and run like crap wouldn't go above 35 mph. Now it sometimes runs like its on two cylinders. It randomly dies and now stumbles and runs terrible. And sometimes it'll come back to life and run fime. I have checked the coils for cracks their are none. They meet the ohm spec one being 2.8 and the other at 3.0 ohms. And the pickup coils tested good. When I check for spark all four cylinders have spark. I'm lost any help is appreciated

 

I started reading this thread and it almost started to sound like the time I exploded a piston.

What are your compression numbers like? Any excessive oil consumption? What do the plugs look like?

 

Start it up in the dark. I bet that you'll see a lightshow. Cracked plug wires are more common than cracked coils, and you can't always see the cracks.

 

I have two sets of coils and and both do the same thing ill test tonight to see if their are any shorts. And the plugs are blackish grey. The bike doesn't use a drop of oil

 

Unless you bought one of those sets new, they (and the plug wires) are the same age, and likely have the same problem. But as with all things there are other potential culprits; check the easy things first.

The blackish-grey indicates either a rich condition, or an ignition(spark) problem.

 

Yes that was most likely from when I tried to ride it home. The coils were new and I have now reinstalled the old ones and it did the same thing. Currently it is running great I'm unsure why.

 

Update: my original coils seem to have bad wires (thanks k-moe). And the after market set were not sealed correctly and were getting water inside the unit. I have since gotten new coils, wires, and plug caps. All seems good as of my install and 10 mile ride