Is She Runnin Lean?
 

I had a suspicion for a while that the gix has been running lean. I noticed the end of the exhaust is always dry and no carbon build up. Pulled the plugs and they're bone dry. These are all the same plug pulled from the 3rd cylinder from the left if your sitting on the bike. Way to lean?

Bike is stock with only a TiForce slip on.

What do the other plugs look like?

I only pulled the one.

I'd check the others too just to be sure.

What's her name?

Stop using 87 octane. At high RPM the cylinder pressure will cause detonation. Even if it's not detonating the fuel burns too fast. 93-94 will burn slower and richen the mix.

Ok so I pulled them all and they're all the same.

Yep, I'm gonna do this for NJMP on the 20th...see what happens.

I think they are OK, just slightly on the lean side. If the suggestion to run higher octane doesn't change anything, I would look into richening the fuel/air ratio via power commander or similar device. I am with Raplh though, why would you run 87 octane on the track?

Higher octane in and of itself is only delays ignition, it does not increase the fuel/air mix. Detonation is an issue, but if the bike does not have a detonation problem, raising the octane level really won't change anything. The ratio is still the same. Lean.
When you put the slip on pipe onto your bike, the back pressure dropped in the exhaust. This allows more volume of air to move through the engine, the fuel was not adjusted and now the air ratio is slightly higher than the fuel at stock settings.
Some pipes can be run with nothing adjusted. Some can't.

You can also put in a fresh set of plugs and the OEM can to see what happens when you increase the internal back pressure to the exhaust. It will become more rich because of the lessened volume of air going through the motor.

Horsepower is a direct result of moving the most fuel and air through the motor in the least amount of time. Pipes, cams, pistons, and all related engine work is dedicated to this goal.
When you put a slip on system onto a bike, generally all that happens is the bike has lower exhaust back pressure and you get an increase in sound, and internal engine heat from burning a higher volume of air. Burning more air without increasing the amount of fuel is the definition of a lean mixture.
Richening the mix will cool the motor and increase power output, it also drops your fuel economy. On a track bike this is not really a concern.

Demand for octane is a result of higher compression ratios. A motor with high enough compression or residual internal engine heat can detonate fuel just based upon compression in the cylinder (like a diesel engine) which generates heat on the compression stroke. New fuel enters the cylinder at the begining of the compression stroke with the piston coming back up and a low octane fuel runs the risk of detonating prior to the piston reaching slightly before TDC where the spark plug kicks in. Detonaton is harmful to the engine and robs serious power from a motor. Detonation attempts to push the piston back down prior to getting to TDC while its still rising on the compression stroke. Due to piston location, the compression is terribly low and that stroke fails to make power. The detonation itself is harmful to the piston, rings, connectiing rod, crank and combustion chamber.
Simply adding higher octane won't cure the issue of a lean mix, it will just prevent the risk of detonation. The amount of fuel still has not increased sufficiently to enrich the mixture going into the motor.

Another indicator is the engine temp. With stock exhaust, take note of the engine temp. With the slip on, it should read a somewhat higher operating temp if its lean and the plugs will be darker.
http://www.dansmc.com/Spark_Plugs/Sp...s_catalog.html
Ken

Higher octane in and of itself is only delays ignition, it does not increase the fuel/air mix. Detonation is an issue, but if the bike does not have a detonation problem, raising the octane level really won't change anything.

It burns slower therefore riching up the mixture.;)

Chris,
a fuel that burns slower does not enrich the mixture. The FI system throws in a pre-determined amount of air/fuel. A higher octane fuel just prevents detonation nothing more. Unadjusted, the amount of air and fuel remain the same, lean. The bike left the factory with settings lean enough to pass emissions. Adding a less restrictive exhaust just allowed for more air to pass through but not more fuel unless intentionally increased which in this case it was not. Not every bike computer can handle the drop in back pressure and "self adjust" adding more fuel for the performance pipe.

To richen up the mix, you have to adjust the FI system to allow for more fuel to air that's going into the motor.
A slower burning fuel in an insufficient quantity will still result in a lean mixture. There's nothing magical about high octane fuel. You still have to add more of it to the engine to call it rich. I would bet that if Joe simply switched to high octane a new set of plugs will come out looking pretty much the same.
If not, I will buy you a beer...;)

Ken

Ok,but I want the beer either way.:drink:

Power Commander, that is all.

Done, congrats on the CCS Championships this season!
Ken

Ok so I had to take care of something and was near WCW...stopped in to show Ron the plugs. Hey said they look just fine, no need to add more fuel...'specially that it has a stock air filter. Also said 87 is just fine but won't hurt anything to see how it reacts to other octanes. Out of curiosity, I'll try some 93 at NJMP and pull the plugs to see what they look like(fresh plugs obviously.)