I bought a 07 zx14 this week, ran great on test drive and loaded it up.

It's stock except M4 pipes on it. I was only on it for a bit but it had a small backfire when backing off throttle.

It wouldn't start after I got it home and sat for a few days, I pulled the plugs and they are black. I'll replace them in the morning I think that'll fix the issue but want to make sure this doesn't happen again.

I read about the PC but am concerned I'll mess up the programming as I'm not a Mecanic or tuner. Is there a more ample fix or any insight would be awesome.

Thanks guys,
Aren

* Last updated by: dsspro on 2/26/2017 @ 5:35 PM *

I'm going to bet that is #4 since that is the easiest one to reach.

Here's my plugs after ~47,000 miles of service in my 08.

#4 looks worse and they get cleaner as they go toward the left. The bike ran just fine with these plugs. Installing new plugs didn't make a bit of difference (although I'm glad i did it).

You may be running rich in places if you got a backfire at partial throttle. 0 throttle deceleration, it will pop around 3500 rpm with aftermarket exhaust. You might be able to tune it back some if you use a different map. You don't need to be a tuner to change maps, just a few clicks of the mouse. Maybe you have a full system map in there right now.

If it won't start, I think you have something else going on. Battery at normal voltage? i think it should be over 12v. About 14 is normal for when the bike is running. Fuel pump clogged, maybe?

I pulled all 4 plugs and they looked the same. I'll go snap a photo of the bottom of the pipes to see if there factory or aftermarket, I think he just did a slip on.

It would crank fine, It wouldn't kick over but did have a popping sound here and there with some backfire sounds.

The guy I bought it from only drove it a few times and it sat, it was dropped in the truck when he loaded it up to his cabin once.

I filled the tank up with fresh gas, I brought the battery up to batteries plus and it had 170cca and read at 12.7.

Sorry I haven't bought a PC yet, just read some posts where people have used them to fix the popping.

Too bad you can't check compression. Change the plugs. Change the air cleaner. Say it looks rich and the air cleaner is how clean? If say it was oil passing the rings and not dry looking like Rook's #3 plug, the threads would be more wet. Only 200 miles or less and if the porcelain tip is wet = Poor compression, aka, ring seal.

Those aren't burnt, they're fuel- or oil-fouled. Fuel-fouling doesn't happen too often with EFI engines, so I would suspect the integrity of the piston rings. Some new plugs and a change to full-synthetic motorcycle oil might help.