F4 2010 Exhaust
1 - 19 of 19 Posts
Joined
·
55 Posts
Please describe further? I take delivery of my F4 in two weeks. Thanks
Joined
·
860 Posts
Joined
·
55 Posts
Can you be more specific? There is one main big nut in the middle where I would guess the valve itself sits flanked by the two nuts on either side where the wire is. Should we unscrew both nuts and then the wire will slide off? Those nuts were a bitch to turn. I can post pics late tonight if that will help when I get off work.
Joined
·
55 Posts
How does it work to unleash the volume? Any performance gains or loss?
Joined
·
55 Posts
I guess if it works, it would be worth the short time it takes to accomplish. Look forward to the pics. Thanks
Joined
·
55 Posts
I wonder if the difference in sound is akin to when you hit 5K RPM and you both hear and feel a slight surge. I played with revs a good bit today and noticed 5000 is were the low end comes to life. Does keeping the valve open effect that? Also, would you say you are now content with the sound decibels or is this just a temporary fix until an after market exhaust can be put on? Do they not make a cat delete for the bike yet?
Where are the pics man??? I'm off work tomorrow and want to get this done!
Where are the pics man??? I'm off work tomorrow and want to get this done!
Joined
·
240 Posts
The valve 'fails' open. I think the valve is closed at idle and low rpms, after that is when it opens. So when disconnecting the cables, it stays open all the time.
It defiantly louder at idle as I've can hear side by side with dads bike that has not had the mod done.
Even though people will argue if it affects performance at low rpm. I cannot notice any difference at all. I really think its there to dampen noise it idle.
As for removing the cables. You should not have any problems at the valve end as you can see everything (remove the exhaust heat shield). At the other end is a bit more tricky as its very confined, hard to see, cant get fingers in, etc. Some people remove the tank to get access more easy, but me and others did it by pushing on the cables to line up the cable with the exit slot of the servo and used a screw driver to dislodge the cable. In the end it was very easy, but its fidgety. Keep your cool, haha.
Have a read here too. More information.
http://www.mvagusta.net/forum/showthread.php?t=45994
It defiantly louder at idle as I've can hear side by side with dads bike that has not had the mod done.
Even though people will argue if it affects performance at low rpm. I cannot notice any difference at all. I really think its there to dampen noise it idle.
As for removing the cables. You should not have any problems at the valve end as you can see everything (remove the exhaust heat shield). At the other end is a bit more tricky as its very confined, hard to see, cant get fingers in, etc. Some people remove the tank to get access more easy, but me and others did it by pushing on the cables to line up the cable with the exit slot of the servo and used a screw driver to dislodge the cable. In the end it was very easy, but its fidgety. Keep your cool, haha.
Have a read here too. More information.
http://www.mvagusta.net/forum/showthread.php?t=45994
Joined
·
152 Posts
Make sure not to leave it hanging while the bike is on. The exhaust will melt the tips when hot.
Joined
·
152 Posts
Joined
·
119 Posts
The exhaust butterfly valve is designed to perform 2 functions:
1. To reduce noise by changing the length of the sound wave exiting the cylinder. The purpose of this is to meet noise regulations; and
2. To add a little back pressure in the cylinder at low revs. The purpose of this is to reduce the amount of unburnt fuel at low revs due to cam overlap and therefore reduce the amount of conversion required in the catalytic converter - reduced emissions.
Leaving the valve open will not improve performance to any measurable degree but may have a placebo effect on the rider.
By all means - do it for noise...for aussie riders - note that this is just another method to pick up a ticket...at least you will know how to fix it for the follow-on EPA tests...
1. To reduce noise by changing the length of the sound wave exiting the cylinder. The purpose of this is to meet noise regulations; and
2. To add a little back pressure in the cylinder at low revs. The purpose of this is to reduce the amount of unburnt fuel at low revs due to cam overlap and therefore reduce the amount of conversion required in the catalytic converter - reduced emissions.
Leaving the valve open will not improve performance to any measurable degree but may have a placebo effect on the rider.
By all means - do it for noise...for aussie riders - note that this is just another method to pick up a ticket...at least you will know how to fix it for the follow-on EPA tests...
1 - 19 of 19 Posts
Join the discussion
Join now to ask and comment!