Yesterday morning I left my driveway and about a quarter mile down the road and the bike started sounding funny. Still ran ok, but the sound was off. I turned around and went back to the house and the bike still sounded off. It idles ok but just doesn't sound right. It sounds like its only running on one cylinder. I put my hand over the exhaust and the front cylinder feels twice as strong as the rear one.
I just changed the plugs two weekends ago so I'm hoping its either a loose plug wire or maybe a bad one. I'm also going to check for a cracked intake along with inspecting the plugs I just installed. A compression check will also be done if needed.
The bike ran rough in the mornings when I bought it last month and before I changed the plugs. Afterwards the bike ran great in the morning but Thursday it started back firing thru the intake when it was cold but a mile from the house all would be fine.
Any other suggestions on where I should check?
Thanks in advance for any suggestions!

Sticky valve syndrome?

How did the plugs look when you changed them? Were the ones from the rear cylinder black and carboned up?

davej wrote:
How did the plugs look when you changed them? Were the ones from the rear cylinder black and carboned up?
They were well used, but nothing terrible. The bike has 26k on it and im thinking they might be the origional NGK's

Look REAL close under the tank and make sure there is no metal parts near the flag terminals on the coils. I’ve had the throttle cable bracket on the carbs short on of my coil signal wires before.

I found the new plugs that I installed were black with carbon. I cant help but wonder if the PO messed with the carb after he installed the bak or maybe he didn't and that's the problem.
I've got a K&N filter that was pretty dirty and I cleaned really well last night. Hopefully that will help.
What are the proper carb adjustments when installing a bak?

thatjeepguy wrote:
I found the new plugs that I installed were black with carbon. I cant help but wonder if the PO messed with the carb after he installed the bak or maybe he didn't and that's the problem.
I've got a K&N filter that was pretty dirty and I cleaned really well last night. Hopefully that will help.
What are the proper carb adjustments when installing a bak?

You also have aftermarket exhaust so a rejet would have been required. The jetting he would have installed would have depended on what jet kit he used. The different kits use different brand jets and their sizing numbers are all different. The needles on a couple kits are pretty close to being the same but some others are different in diameter, it just depends on the kit brand. If the filter was real dirty and you cleaned it just ride and see what happens. There is a real good chance the jetting is just too rich and will need to be changed. That wouldn't be uncommon with some of the jet kits out there. If it carbons up after a short time ( a couple rides should tell) you will need to get into the carb to see what size jets were installed. From there we may be able to figure out what kit was used based on the jet sizing and/or brand of jet and do the proper adjustments to get it corrected.

The fact that I'm getting 25mpg and the black plugs lead me to believe the bike is getting more fuel than it needs.
I rode the bike for about 150 miles Saturday with no issues. I'll check the plugs again this weekend to see what's happening.

If you pull the carb apart, get a OEM needle and seat set, to swap out for the originals. If it is the original set, it's time anyway.