2005 EGC with Stage 1, SE A/C, Andrews 21G cams, and free flow mufflers on V&H Dresser Dual headers, with 34K miles on them. They're loud, and it's clear the packing is worn out of them.

The AFR's on my bike are out of wack, in the low 13's. I need new mufflers and will likely go with SuperTrapp SEII's. But I'm wondering if the 2005 vintage stock mufflers will achieve a similar result. Theory being the more restrictive exhaust will bring up the AFR's.

Nobody has suggested this.....I'm just thinking/typing outloud. Make any sense?

 

your air to fuel ratio is about right for a performance tune.. low thirteens is a pretty fat mixture. the higher flowing air cleaner which you already have, along with the higher flowing mufflers will lean your motor out just a bit more. remember, more flow through the intake and through the exhaust will tend to lean a motor out rather than richen it up. sounds like it ought to be a great combo. if you notice much popping on deceleration, that could indicate that your mix is a bit on the lean side. your afr's aren't out of whack at all, matter of fact, that low 13s to 1 air to fuel ratio is optimum for performance.

 

OK...How does this look?

 

Awful. On a wot pull you should see your afr line around 13:1. What is posted on your sheet is (assuming it's efi) is uncalibrated ve tables. Lack of proper documentation on that dyno sheet makes it impossible to know what it is showing. Lets asuume it is showing front and rear cylinder afr lines at wot..The blue line is lean until 5250 rpm. The red line is lean, rich and not good anywhere. Switching exhaust is not going to cure anything. What do the afr lines look like a the other 10 throttle positions? Was this just a wot throttle pull to see what your afr looked like? Sure hope it wasn't a tune. I have attached a picture of what your afr lines should look like after your ve tables have been sychronized. This is the first step in tuning a bike and it is done to a value of 13.2:1 or 13.5:1 depending on the tuning device. Once these tables are set then the afr table can be set to 14.4-14.5 for your cruise area's and as rich as 12.8 - 13:1 for heavy load and wot areas of your map. When your bike has lean spots like that you will be prone to pinging issues and were it is excessivly rich you get poor milage and excessive piston ring wear. When your bike is properly tuned it will run cool, have good fuel milage and the hp and torque lines will be smooth. Smooth lines = happy bike.

 

Nice explanation. It's EFI with a stage one download. Not a tune, just a run to see where it's at. I attached the other 2 sheets below. I've been putting off getting a tuner, but I guess it's time.