Engine Failure?

Was going on a ride yesterday, when the engine suddenly began running very rough. The exhaust noise increased substantially, and the engine would not run at idle without cutting out. A small amount of smoke also is present in the exhaust. I had noticed that since the valves were adjusted at the dealer, that there was a different top end noise present.
Has anyone run into this situation before?

Aftermarket parts?

My commander III was intermittent causing similar problems.
Check all of your aftermarket parts.
Red Rider

Aftermarket parts.

They did disconnect the Cobra control module, and nothing changed. I guess this would rule out this issue. Thanks for your input!

Engine running on 1 cylinder

Appears after some trouble shooting, that the engine is running only on the rear cylinder.
Pulled the plugs and while turning over the engine I have spark on both plugs.
Bike is at the dealer, but after four hours they cannot seem to identify the problem.
Any ideas?

"Running On One Cylinder";

Hi Crackerjack,

Seeing that your problems seem to have started after your valves were adjusted, I would look at these items.
First,---- I would check the engine compression to see if it is correct,----possiblity of a valve being adjusted too tight & letting compression bleed pass an open valve.
Secondly-----If compression is OK, & you stated you have spark, look at fuel, that being a possible of a bad fuel injector, or a loose electrical connection to the fuel injector,---- seeing they were in there adjusting the valves.
To me this would be two oblivious items to start checking first. Hope this will help you out Crackerjake.

All my best, kritter.

4 hours

If they can't identify the problem after 4 hours it is time for a new dealer.

Really simple stuff. I takes 4 things to fire. Spark, fuel (all the way to the cyl), compression, timing.

Compression is real easy to test. same with timing as both cyl run off of the same crank trigger.
So it is probably spark or fuel. You say you have spark, but is it enough? A bright spark, or a weak spark? If it is questionable, just change the plugs. It could be cross arcing under compression.
If you saw it, it is probably OK, so that leaves fuel.

If it is running on one cyl, that means the pump is working. so the next step is to check for a power and ground at the injector. take a test lite and hook it between the two wires (NOT to a power or to a ground, only between the two wires) If you have a good pulse when cranking, the computer is working and you have a bad injector. If no pulse, the check for power at one wire with the key on. If you have that, the computer is not grounding it.

This should take a dealer less than an hour to do it all.

Work as though you would live forever and live as though you would die tomorrow.


Compresion on both cylinders looked ok. Spark is present, but I am not sure how strong a spark was present. No updated news today, will have to wait until Tuesday now. Thanks for the input!


It does not sound like an engine problem, it sounds like a fuel problem and it has fouled the plugs. Make sure both vacuum lines from the throttle body to the Map sensors are plugged in and maybe even test for codes.

You will probably have to change the plugs also.

Work as though you would live forever and live as though you would die tomorrow.

Map sensors

The plugs look like they have been running a rich mixture and slightly fouled. They did change the plugs. Both vacuum lines from the throttle body were plugged in. Last I heard when they unplugged them they were able to have both cylinders running? Will have to confirm if I understood correctlly tuesday.


This certainly could be a possiblity I will have to investigate. I will scout out the vacuum lines and look into the service manual on how to test for codes. Thanks for the feedback! I wasn't origionally convinced it was a plug as it seemed to come on so suddenly, as I perceived a fouled plug would be something that occured over a time period.

jeffb Again...wonder if

jeffb Again...wonder if dealer did not turn the petcock back on after servicing...a common occurence.

Pet cock.

That did occur to me, however I have travelled through numerous fuel tanks since servicing. Thanks for your input!!

Petcock closed

I have driven numerous tanks already since the servicing so I believe I could rule this out.