Very surprised at the results of this experiment

[Alien]

Very surprised at the results of this experiment but I'm looking for some reassurance.

In my other posts you can read about how I am looking to quiet down my Vmax.

Someone posted about packing the pipes with steel wool.

At first I was skeptical but I figured let me spend six bucks and try it.

I put a 1 inch dowel down the center of the pipe and packed steel wool around it.

I pulled the dowel out, started the bike and went for a 4 mile ride and was astonished!

The sound is throaty but much quieter. I can ride without ear plugs without any discomfort.

I do notice a very slight drop in power but nothing serious. I didn't notice any other problems. The bike ran smooth, didn't stutter or do anything stupid.

I know it'll degrade quickly and be blown out. I've read the pros and cons.

I'm really just concerned with somehow causing damage to the engine.

So my question is this; if I keep riding like this for a while until I come up with a permanent option, will this cause any damage to the bike considering it has stage 7 jetting?

 

[jfeagins]

Steel wool rusts -

 

[blaxmax]

It doesn't go into the engine only out of the pipe. Since you have less back pressure you could rejet but it will slowly correct back to where you were.

 

[Traumahawk]

This will not harm the jetting in anyway. Now the change in back pressure isnt optimum for HP, but with a stage 7 bike, your probably making in the neighborhood of 120, so a couple of hp isnt gonna make that much of a difference.

 

[Dorney]

If I understand you right you stuck the dowel down the center of the muffler? If so there's nothing to hold it in there & if it tries to blow out from the back first it may ball up & plug the exhaust. Buy some pipe packing drill out the rivets at the end of the muffler pull the end cap off. If the baffle comes out take pipe packing & rap it around the baffle you can take wire & rap it around the packing to hold it in place. If the baffle doesn't come out put the packing in the best way you can put cap on rerivet & your good to go.

 

[blaxmax]

This will not harm the jetting in anyway. Now the change in back pressure isnt optimum for HP, but with a stage 7 bike, your probably making in the neighborhood of 120, so a couple of hp isnt gonna make that much of a difference.

There is NO difference between running a full pass with a fully packed baffle and an open header? I don't think so. It does make a difference in the jetting and I have spent a lot of time doing it on the track. You will be surprised to see how many professional racers run baffle packing. Few if any. EVERY time I fill a baffle on a stock pipe I rejet.
Why would you put on an aftermarket exhaust then if you didn't want it to flow more?

 

[Alien]

I recently bought this bike and it already had the exhaust installed. I'll be switching to s quieter exhaust at some point. In the meantime, I'm just experimenting with different options.

 

[blaxmax]

Alien, that last question was general and not directed at you, I hope you understand. Most rider put an aftermarket pipe to enhance performance.

 

[Traumahawk]

I recently bought this bike and it already had the exhaust installed. I'll be switching to s quieter exhaust at some point. In the meantime, I'm just experimenting with different options.

Here's the reason why I said this. On a Vmax with CV carbs, with an aftermarket exhaust, you will flow more air out of the carbs, so in turn you will pull more air into the carbs. With that....you pull more FUEL as well, so you in fact enrichen everything up. The stock jetting of a Vmax is 152.5's, and with an aftermarket exhaust most people find that they run better and more HP with 150 or even 147.5's for main jets.

So, with the extra "baffle", since youve changed the amount of air that you are flowing, youve changed the jetting requirements, but not a lot. Like I said, you might have lost a couple of hp, but with a stage 7 bike, it wont really make a difference.

Here is the very first thread that I ever started, and of course it was about carbs. The people that answered on this thread are the real carb gurus of this forum.

http://www.vmaxforum.net/showthread.php?t=25903

 

[blaxmax]

Here's the reason why I said this. On a Vmax with CV carbs, with an aftermarket exhaust, you will flow more air out of the carbs, so in turn you will pull more air into the carbs. With that....you pull more FUEL as well, so you in fact enrichen everything up. The stock jetting of a Vmax is 152.5's, and with an aftermarket exhaust most people find that they run better and more HP with 150 or even 147.5's for main jets.

So, with the extra "baffle", since youve changed the amount of air that you are flowing, youve changed the jetting requirements, but not a lot. Like I said, you might have lost a couple of hp, but with a stage 7 bike, it wont really make a difference.

Here is the very first thread that I ever started, and of course it was about carbs. The people that answered on this thread are the real carb gurus of this forum.

http://www.vmaxforum.net/showthread.php?t=25903

And pay attention to the alterations of the carb changes as you read it.

 

[Alien]

Based on the results of this experiment, I think I'm going to build my own removable slip-in baffles.

 

[Traumahawk]

Based on the results of this experiment, I think I'm going to build my own removable slip-in baffles.

Thats cool, please post how it turns out.unk:

 

[jfeagins]

Plenty of room to experiment with baffles in a pair of cans like these.

 

[MaxMidnight]

Here's the reason why I said this. On a Vmax with CV carbs, with an aftermarket exhaust, you will flow more air out of the carbs, so in turn you will pull more air into the carbs. With that....you pull more FUEL as well, so you in fact enrichen everything up. The stock jetting of a Vmax is 152.5's, and with an aftermarket exhaust most people find that they run better and more HP with 150 or even 147.5's for main jets.

So, with the extra "baffle", since youve changed the amount of air that you are flowing, youve changed the jetting requirements, but not a lot.

Initially the maximum charge a cylinder can receive is dependant on how much the piston can suck in on its downward stroke.

This would then be alterered by restrictions within the system (air box, filter, carb throat, inlet shape etc.) and the harmonics of the inlet tract.

There are pressure waves that move up and down the inlet and exhaust systems.
Get the timing of the pressure waves right on the inlet, that is a positive pressure wave occurring when the inlet is open, additional charge can be introduced into the cylinder.
However, the maximum benefit is gained over a relatively narrow rev range.

Similarly, the maximum scavenging (that is how much of the burn gases that an exhaust can extract) will depend on the harmonics of the system. I'm not sure if this is what previous respondents are referring to when the use the term 'back pressure' or not.
One again the length and diameter of headers and collectors together with the routing of the pipes are what influence how an exhaust will perform.
In this case a negative pressure wave arriving when the exhaust valve is open will pull out the burn gas and if the inlet has started to open some of the fresh mixture. Ideally a positive wave will arrive just before the exhaust closes and push some of this fresh charge back into the cylinder.
Get it wrong so that a positive wave occurs too soon when the exhaust valve is open then this could result in unburnt gasses remaining in the cylinder or in a extreme case during the overlap travelling back to the carb (called reversion)

From the above then changing the diameter or length of an inlet or exhaust will affect where maximum torque will occur by altering when negative and positive pressure waves arrive at the inlet and exhaust valves.
Those of us who suffered the 'joy' of being taught the recorder at primary school are already familiar with this principal. The covering of the holes will change where the max. and min. pressure wave occur and thus the note produced, i.e. you are tuning the pipe.

What Mr Allen has created by introducing steel wool is an absorption silencer.
Rather than steel wool (which will blow out) then one of the products designed specifically for the task may be mor appropriate?

 

[Traumahawk]

Initially the maximum charge a cylinder can receive is dependant on how much the piston can suck in on its downward stroke.

This would then be alterered by restrictions within the system (air box, filter, carb throat, inlet shape etc.) and the harmonics of the inlet tract.

There are pressure waves that move up and down the inlet and exhaust systems.
Get the timing of the pressure waves right on the inlet, that is a positive pressure wave occurring when the inlet is open, additional charge can be introduced into the cylinder.
However, the maximum benefit is gained over a relatively narrow rev range.

Similarly, the maximum scavenging (that is how much of the burn gases that an exhaust can extract) will depend on the harmonics of the system. I'm not sure if this is what previous respondents are referring to when the use the term 'back pressure' or not.
One again the length and diameter of headers and collectors together with the routing of the pipes are what influence how an exhaust will perform.
In this case a negative pressure wave arriving when the exhaust valve is open will pull out the burn gas and if the inlet has started to open some of the fresh mixture. Ideally a positive wave will arrive just before the exhaust closes and push some of this fresh charge back into the cylinder.
Get it wrong so that a positive wave occurs too soon when the exhaust valve is open then this could result in unburnt gasses remaining in the cylinder or in a extreme case during the overlap travelling back to the carb (called reversion)

From the above then changing the diameter or length of an inlet or exhaust will affect where maximum torque will occur by altering when negative and positive pressure waves arrive at the inlet and exhaust valves.
Those of us who suffered the 'joy' of being taught the recorder at primary school are already familiar with this principal. The covering of the holes will change where the max. and min. pressure wave occur and thus the note produced, i.e. you are tuning the pipe.

What Mr Allen has created by introducing steel wool is an absorption silencer.
Rather than steel wool (which will blow out) then one of the products designed specifically for the task may be mor appropriate?

And that people, is the SCIENCE behind tuning. unk:

 

[Alien]

Steel wool was used as a cheap medium to see how sound would be affected.

When I build baffles, I'll be using a more appropriate material.