running lean

[icemanec63]

hello all ,just wanted to ask ,if anyone has put on a set of slip on cans ,[i put muzzys on ] and a k/n air filter,with out a power commander on ?does anyone think this would hurt the motor ,i have done this on my 2005 fjr .it seems to be running a little better off the bottom end ,but just a little bit weaker on the top end,mpg seems to be a lil better .i had to turn the idle up just a little bit .but it seems to be running just fine .some one told me i could burn a hole in a piston .does any one think this could really happen!!

 

[joebiodiesel]

hello all ,just wanted to ask ,if anyone has put on a set of slip on cans ,[i put muzzys on ] and a k/n air filter,with out a power commander on ?does anyone think this would hurt the motor ,i have done this on my 2005 fjr .it seems to be running a little better off the bottom end ,but just a little bit weaker on the top end,mpg seems to be a lil better .i had to turn the idle up just a little bit .but it seems to be running just fine .some one told me i could burn a hole in a piston .does any one think this could really happen!!

Can you hole a piston by running a 4 stroke lean? Absoutely.

Will slip on cans lean your FJR out enough to cause that to happen? I don't know.

If it did happen it would do it while you were topped out, and you say that's where the power has changed...

 

[SkooterG]

I think many around here have added slip-ons and K&N without remapping of any kind. I think the conventional wisdom is that it really doesn't change much adding those items. And remember, lots of FJRs (especially Gen I) run lean without any mods.

Personally, I think your butt dyno is off. I don't think adding K&N and slip-ons really increases the FJR's HP much if at all

 

[wfooshee]

But the K&Ns do increase the grime intake for the engine.

HaulinAshe has information for you on that.

 

[C&C]

If your O2 sensor is working I wouldn't think your engine would run any leaner than the computer is programed to run it.

 

[ionbeam]

If your O2 sensor is working I wouldn't think your engine would run any leaner than the computer is programed to run it.

Unless you are droning down the highway the engine is in the closed loop mode so little that the O2 sensor is out of the picture most of the time. If the engine is lean enough to be a problem the exhaust pipes may blue from the heat, the headers may glow brightly at night, the engine may knock and the temperature gauge will run on the high side.

Look at the plugs, if there is any problem you will see it when you look at the plugs. A white, glazed looking center insulator is not good, any hint of melting is bad, erosion of the center electrode or ground strap is not good. If the plugs are a normal tan color and the electrodes are normal then things are fine. Bring the engine up to operating temperature, try to keep rpms over 3k, pull into the driveway and immediately shut off the engine. This will give you a pretty accurate color on street engine plugs.

 

[SkooterG]

But the K&Ns do increase the grime intake for the engine.

HaulinAshe has information for you on that.

Agreed about the K&N. I didn't use mine for very long before I went back to OEM air filters.

 

[Geezer]

I have been running a full Muzzy 4-2-1 system and a UNI oiled foam air filter for more than 50k miles on my '05 with no changes to the fuel delivery. No Power Commander or other aftermarket product. Not even the Barbarian jumper mod. There are no signs of lean running on the spark plugs and no knock in the engine.

 

[charismaticmegafauna]

Maximum heat is produced when the engine is producing maximum power.

In the '60s, Honda claimed that their motorcycles were designed to run at 75% of maximum -- continually. I'm pretty sure the FJR is at least that good/durable.

'Running lean' is good -- IF you can get around "driveability" issues... :blink:

Often, the rider/driver just can't/won't accept flat spots in acceleration or surging or etc.? :huh:

The leaner -- The better (mandated EPA emission controls, of recent decades, have given us the best IC engines we've ever had...). Except, re emissions, leaner may be too cool...

From an engineering text:

"If the AFR is GREATER than stoichiometric we can obtain

complete combustion but we may be supplying too much air

thus reducing the temperature of combustion ..."

 

[icemanec63]

thanks for the feed back.i think im going to put in a new oem filter in ,and see if i can still tell a differance

 

[Tree Doc]

thanks for the feed back.i think im going to put in a new oem filter in ,and see if i can still tell a differance

You likely won't notice a thing and if longevity is what you prefer in an expensive engine, your FJR will thank you for the OEM filter.