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Running on 2 Cylinders

8.3K views 10 replies 6 participants last post by  Just_Nick  
#1 ·
2003 GSXR 600, It's running on only the outside cylinders. I'm hoping I haven't blown the motor, but I'm not too optimistic. Fuel pressure is 43 PSI, Flow test is to spec as per manual, I got spark on all 4 cylinders, only thing I can think of other than that is out of time, or I blew the rings... Anyone got any ideas on what else it might be? I'm pretty much out of stuff that I know how to do, and I'm going to drop it at the dealer and see what they can find out. I've gotten 16,000 miles out of it this year so now I'm just hoping I can get it back to running right and put 20 on it next year. Any feedback would be much appreciated.
 
#3 ·
^ What he said.

Fuel, air, spark are what you need.

Since you have spark your next step is to check if you have compression. It does not have to be fancy, you are just making sure it is not near zero in the center cylinders.

Did this happen suddenly?

Did it happen after you worked on it? (I'm thinking the ignition coil leads on #2 & #3 may be switched)
 
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#4 ·
I don't see how the leads could be switched as they are set lengths. I have suction on all 4 cylinders when I put my hand over the throttle bodies when it turns over. I believe that tells me that I have compression on all 4... I assume that a gauge would tell me better than that.
 
#5 ·
Having suction on all throttle bodies sounds reasonable as a check. I've never done it that way. I usually just put my thumb over the spark plug hole but of course that is near impossible on these engines.

I'd spend the $$ to get a compression tester set. They seem readily available for about $20. High accuracy is not a big factor as the important part is to compare the readings on all the cylinders.

You might also check your local auto parts store for a loaner tool.

Most problem solving is by the process of elimination and you really want to eliminate a mechanical issue right at the start.
 
#6 ·
Agree with previous.

By 'only running on the outside cylinders', just how are you determining that?
If you 'have spark' on the inside cylinders, and fuel flow, and suction/compression?
Are you seeing if the headers are getting warm/hot on those cylinders?
Sorry for not knowing, but is the 03 600 FI, of Carb?

With any properly serviced bike, oil changes, etc. which I"m sure yours is
Rings don't just wear out quickly, and when they do, usually all wear fairly evenly too?

Did you recently do any work to the bike? Did it happen kind of suddenly.
 
#7 ·
I'm guessing you've done the "swap the running two to the non-running two" test, as well? IE, spark plugs, coils, and fuel injectors?
 
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#8 ·
Yeah, I did that and still only got the two outside cylinders to run.
The 03 600 is fuel injected.
The issue happened just after I changed the spark plugs... I haven't been able to get it right since then. I really don't know what else to do with it, I gave up and took it to the dealer and they're going to run through the bike and see what they can find for $120. Right now thinking that I should just get an 03 1000 and use this one as a parts bike....