Is there any risk of damaging the motor with an exhaust gut?

I gutted my muffler today and my dad thinks it could burn the valves. Is there any truth to this?

[image: View Post]blackbrainedjohnny, on 22 February 2010 - 12:14 AM, said:

I gutted my muffler today and my dad thinks it could burn the valves. Is there any truth to this?

Doubt it, you probably didn't increase flow much at all really, a test ride should tell you if you leaned it out that much with increased lean-miss in the mid-range.  If you achieved more than 10% more flow out of the cans doing that I'll be surprised, and at certain RPM's they may actually be worse now.  Although you also blocked off the left side can; assuming you did that by plugging the under-tail y-pipe at the pipe itself, so there may be some improvement there (that factory setup is so crap...) so it's hard to say without a flow bench.

Take it for a ride and see what it's like.

[image: View Post]blackbrainedjohnny, on 22 February 2010 - 12:14 AM, said:

I gutted my muffler today and my dad thinks it could burn the valves. Is there any truth to this?

Isn't it a restriction thing will burning valves,and isn't most of the restriction on the motor side of the "Cat" systems? Otherwise, the same thought would be true for any freer flowing slip-on... :comp13:

One member here completely gutted his - I mean completely it was like a trombone, it ended up dumping raw fuel into the exaust and catching fire, ruined his bike.  Billyjackjimbob is his name and the bike was called "the redneck express" it was obscene how loud that thing was! I am sure he gutted the catylic converter too.

HispanicSlammer, on 23 February 2010 - 12:15 AM, said: One member here completely gutted his - I mean completely it was like a trombone, it ended up dumping raw fuel into the exaust and catching fire, ruined his bike.  Billyjackjimbob is his name and the bike was called "the redneck express" it was obscene how loud that thing was! I am sure he gutted the catylic converter too. Yea, but it must have looked KOOL!

Look at the pic in my avatar.  That's just open pipes.  I've been running like that for over 15,000 miles without a single problem.

[image: View Post]Alien VFR, on 23 February 2010 - 12:56 AM, said:

Look at the pic in my avatar.  That's just open pipes.  I've been running like that for over 15,000 miles without a single problem.


that thing must be pretty loud! Any video with sound?

[image: View Post]blackbrainedjohnny, on 22 February 2010 - 12:14 AM, said:

I gutted my muffler today and my dad thinks it could burn the valves. Is there any truth to this?

Well, since you opened one side and restricted the other, I wouldn't worry about it. Though FI VFR's do tend to run lean as it is...

[image: View Post]HispanicSlammer, on 23 February 2010 - 12:15 AM, said:

One member here completely gutted his - I mean completely it was like a trombone, it ended up dumping raw fuel into the exaust and catching fire, ruined his bike. Billyjackjimbob is his name and the bike was called "the redneck express" it was obscene how loud that thing was! I am sure he gutted the catylic converter too.

Didn't BJJB have an electrical fire? Or was that just a code I didn't pick up on?

I've got over 50k on a set of completely gutted exhausts with catless headers... no issues with the engine so far.  Sounds alot better then stock as well, without being overly loud.

[image: View Post]blackbrainedjohnny, on 22 February 2010 - 12:14 AM, said:

I gutted my muffler today and my dad thinks it could burn the valves. Is there any truth to this?

45,000 on my '03.  30,000 of which are with the exhaust gutted.  Love the sound!  Passed Valve inspections with flying colors.