straight pipes=bad fuel economy?

[smokingness69]

i have an akropovic full race exhaust with carbon fiber muffler on my bike along with the power commander, airbox mod, and pair removal mod. ive been getting 48 mpg with it like this. then one day i hydroplaned and layed the bike down. the swing arm spool on the right side tore into the carbon fiber muffler. it tore a hole about 1 1/2 in wide and 4 in tall. the bike still rode and sounded ok so i rode on. ive been riding it a few times since. each time i rode the exhaust blew more and more packing out of the torn hole in the muffler until there was no more packing left and now it sounds like i have straight pipes. so one day i look at the guages and notice im only getting 24 mpg!!! thats half of what ive been getting. anyway i have taken it to the track like that and i get the same numbers now as before with it so i dont think anything is wrong with the engine. so i was wondering, would a muffler with no packing cause me to get really poor fuel economy???

 

[Con5179]

i get that kind of gas mileage in the city with my Brock/Hindle exhaust with the track map... not sure about your question but...good luck.

 

[Charlesbusa]

48 mpg is really high. Was that straight freeway riding??

 

[smokingness69]

yeah the 48 mpg is riding highway 60 mph. 2 maybe 3 short wheelies. riding out an entire tank of gas. i measured it a long time ago when i first got the bike and got a little over 200 miles to a tank of gas. thats still about 40 mpg before it was broke in.

 

[Charlesbusa]

I would go thru another gas tank and see what you get out of it.

I have a 2002 with a yoshi full system and I get about 40mpg commuting.  And 25mpg aggressive riding in the canyons.



<!--EDIT|Charlesbusa
Reason for Edit: None given...|1129415280 -->

 

[smokingness69]

i was also told that running the busa with straight pipes could bend the valves. is there any truth in that?

 

[TheAtomicAss]

i was also told that running the busa with straight pipes could bend the valves. is there any truth in that?

Bend the valves, or melt the valves? There is a difference.

Haven't ever heard of a motor bending valves because of a change to the exhaust. They can melt though. But they typically only do so when the engine is running lean. Which, given your gas mileage, I would say you're not.

 

[CorrodedAlien]

no back pressure...