GRiSO running on one cylinder?

In an effort to not throw parts at the bike and definitely avoid bringing it to the dealer i figured I would try posting.

While riding down the highway the bike lost power dramatically.  I got it off the highway and found it making far more mechanical noise than usual and it really didn't want to rev.  

Ive searched the topic extensively and everything says replace spark plug boots, well i did that last fall.  I checked for spark and its there.  I pulled the spark plugs and the left side plug was very sooty and seemed a little wet with fuel.  I looked over the wires and boots and installed old plugs i had saved thinking maybe the spark plug has an issue, started it up but no luck.  Still very noisy and revs very poorly.  Both exhaust pipes did begin to warm up, but the left wasn't as warm as the right if that means anything.  

My next thought was to replace the spark plug wires, but figured i would hold off until i checked here.  Any ideas what might be causing this?  Any chance the coil is giving a weak spark?  Any help is much appreciated.

When you replaced the spark plug boots, were they stock boots, or the acclaimed NGK ones?



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NGK's as recommended.

Spark problem is the most likely. You should at least watch the left side in the dark to confirm you're not getting any arcing. Check the connections on the coils as well.


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This, my thought is still spark, it's just so typical.

Any diagnostic suggestions?  My next thought was to switch the wire and plug boot from side to side and see if the issue migrates or stays. That should help prove or disprove the wire/plug boot as the culprit .......hopefully.

Probably a silly question but is exhaust temp a good indicator of how a cylinder is firing?  As I stated the left side exhaust was warm after running but not as warm as the right after idling for 30-45 seconds. I'm looking for an accurate way to tell if the issue swaps sides or not.

Thanks for your help in this topic.

If the cylinder isn't firing properly, the exhaust will run cooler, so yes, it's an indication of a combustion issue.

Any error codes logged?

Swapping the wiring to see if the fault follows is an easy (and good) diagnostic test.


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No error codes

Also if the plug wire and boot swap fails I was thinking of swapping coils from side to side after that.

What year is your GRiSO from?

2012

Has it been rollerized?

came roller from factory.

Than I would indeed toss the right and left ignition parts out. I was a bit worried about the "mechanical noise" part.

Swapped plug wires and both sides seem to be heating up fairly evenly but it's still lacking power and sounds very loud. Then swapped coils same result. I think I might be out of ideas. Unless someone has another idea it may be heading to the shop for a summer vacation.

Check the header nuts haven't come loose.

*Loud*? In what way? Mechanical type loud or 'Frappa-Frappa' exhaust type loud?

If it sounds like an exhaust leak also check the pretzel for cracks and splits. They're near the lambda sensor and will play bloody havoc and mayhem with the closed loop fueling if you're not running an open loop map.

The noise is more mechanical and clunky coming from what seems like the left side not exhaust, but I checked and it's ok. I remember years back starting the bike with one plug wire disconnected (rushing to get finished) and it made a lot more noise than usual. I just can't remember it it was this much. I think I'm starting to over analyze all the symptoms.

Left plug is really dark and sooty I think it got to be spark related. I'm fairly certain it's an issue with the left cylinder. Top end looks ok and when I rotate motor everything seems to be functioning and moving as it should.

Before we go any further can we know what year this bike is?

2012 with factory roller cam

Blow by problem? What's your oil level like? Check for oil in the airbox.

For a start check valve clearance on the both cylinders, (easy job) so we can rule out any problems with the valve gear.

Pete will help you

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The oil level is fine, about half way between the lines on the dip stick.  Right about where i filled it to last November.  Inside the airbox is another story.  Beneath the air filter is clean, but when i opened the inspection cover under the battery it's not only oily but there is grit and pollen in there as well.  

New question, how is dirt getting in the airbox?  If the area under the filter is clean how is it getting in??  Im getting a bad feeling about this......