1994 Kawasaki Ninja 500 only running on one cylinder. Recommended head rebuild place?

[LCDshovel2007]

Hi everyone, and thanks in advance for your help.

I have a 1994 Kawasaki Ninja 500 (EX500) that only runs on one cylinder out of two. I was riding on the highway when I felt a significant loss of power and lots and lots of backfiring out the one side which ended up being bad. I figure I need a valve job at the very least.

Here's the troubleshooting that I've done so far:

The good cylinder gets 180PSI compression, and the bad one gets none at all. Adding a bit of oil into the cylinder doesn't change the reading. I blew compressed air into the spark plug hole while manually turning the crank with the exhaust off, and it seems like the air is always leaking out of the exhaust. This leads me to believe that something is wrong with my exhaust valves in that cylinder.

Aside from that, I've cleaned the carbs, making extra sure the pilot jets were fine, and set float heights to spec with a digital caliper.

Also did a valve adjustment. All the exhaust valves were a little out of spec (too tight) but the intake valves were okay.

Coils are fine too, although I did trim the spark plug leads and put new caps and plugs just because. Switching coils gets the same result - runs well on the right cylinder, doesn't run on the left. Even replaced the IC igniter.

Unfortunately, I don't have the time to learn how to remove the cylinder head atm, otherwise I'd have a much better idea of what's going on.

So far, I feel like I've ruled out spark and fuel issues, and the zero compression is a huge clue. Correct me if I'm wrong, but I'm looking at a head rebuild to start? If so, where do you guys recommend? I'm located in the Kitchener/Waterloo area but I'm willing to travel. Any stories of similar experiences and time/cost figures would be hugely appreciated! Thanks!

 

[TwistedKestrel]

Hi everyone, and thanks in advance for your help.

I have a 1994 Kawasaki Ninja 500 (EX500) that only runs on one cylinder out of two. I was riding on the highway when I felt a significant loss of power and lots and lots of backfiring out the one side which ended up being bad. I figure I need a valve job at the very least.

Here's the troubleshooting that I've done so far:

The good cylinder gets 180PSI compression, and the bad one gets none at all. Adding a bit of oil into the cylinder doesn't change the reading. I blew compressed air into the spark plug hole while manually turning the crank with the exhaust off, and it seems like the air is always leaking out of the exhaust. This leads me to believe that something is wrong with my exhaust valves in that cylinder.

Aside from that, I've cleaned the carbs, making extra sure the pilot jets were fine, and set float heights to spec with a digital caliper.

Also did a valve adjustment. All the exhaust valves were a little out of spec (too tight) but the intake valves were okay.

Coils are fine too, although I did trim the spark plug leads and put new caps and plugs just because. Switching coils gets the same result - runs well on the right cylinder, doesn't run on the left. Even replaced the IC igniter.

Unfortunately, I don't have the time to learn how to remove the cylinder head atm, otherwise I'd have a much better idea of what's going on.

So far, I feel like I've ruled out spark and fuel issues, and the zero compression is a huge clue. Correct me if I'm wrong, but I'm looking at a head rebuild to start? If so, where do you guys recommend? I'm located in the Kitchener/Waterloo area but I'm willing to travel. Any stories of similar experiences and time/cost figures would be hugely appreciated! Thanks!

If you have actually dropped a valve ... you might want to look for another motor instead, will probably be cheaper

 

[Brian P]

The problem here is that for that bike and given its age, the cost of paying a professional shop rate to do all the work will likely exceed the value of the bike. I learned to do this stuff myself. And it's winter, perfect time for a project.

 

[XenoVibe]

If your valve dropped in the cylinder head, wouldn't you hear it rattling around when you blew compressed air in it? Doesn't a hole in the piston make more sense?

 

[LCDshovel2007]

Hey guys, thanks for your answers. I'm figuring the valve seats might be messed up and/or the valves are chipped? From what I could tell peering into the spark plug hole and poking around, the piston itself is solid. Forgot to mention that it does seem to push air back up when I'm cranking it, just not enough to register anything on the compression gauge. I suppose I could block off the exhaust port and see if that changes my reading?

If I find the time, taking it apart does sound like a good winter project, but that doesn't seem likely with my schedule right now. Should I get around to it though, do you have any recommendations for machine shops?

 

[zeniceguy]

Sounds like a dropped valve. U need to pull the head off

Sent from my SGH-T989D using Tapatalk

 

[kneedragger88]

Just yank the head its a quick one on an EX and should be able to find a used one pretty easy. Like Brian said its a good winter learning project,

 

[LCDshovel2007]

Okay, thanks again for the replies. I'm eager to tear it apart when I get back from out of town. If it is a dropped valve, then that's weird to me because when I last took the valve cover off I saw no damage. The offending cylinder's valves were all there (at least the stems were, lol) and the springs were in place too.

Sorry for the crappy cell phone pictures, I took them before knowing what exactly was wrong and so I didn't focus on the parts I think are broken, but everything looks like it's all there??

 

[TwistedKestrel]

For clarification, an actual literal dropped valve is unlikely. However you do seem to have a valve failure of some sort, assuming you did the compression test correctly (I have no reason to believe you didn't). I find that type of failure on an EX500 unusual, but around here everybody seems to save maintenance for the next guy so who knows what caused it. To observe what's wrong, you're probably going to have to pull the head anyway.