Frequently Asked Questions

Select A Question From The List Below:

What’s the difference in Standard, Race and High Sport Mounting?
Why should I purchase an M4 exhaust system?
What should I buy? Full System, Slip-On or Bolt-On.
How much does the M4 system weigh?
Do I need to re-jet or re-map?
What kind of gains can I expect?
What does a M4 exhaust sound like?
What is the difference among the polished, carbon and titanium silencers?
Are M4 exhaust systems street legal?
Do I have access to my oil filter and drain plug?
What kind of warranty do I get with a M4 exhaust?
Are M4 silencers rebuildable?
Can I buy replacement parts for my damaged M4 system?


Q: What’s the difference in Standard, Race and High Sport mounting?

A: Standard
Our Standard Mount follows along the lines of the stock system mounting. You retain your passenger foot pegs and general overall look.

A: Race
Our Race Mount gives you more ground clearance in those tight turns and is tucked in a bit. You do lose your passenger foot pegs as our mounting bracket replaces the foot peg mount.

A: High Sport 
Our High Sport Mount really tucks the pipe in and up out of the way. You do retain your passenger foot pegs.
However, the silencer can is in the way of your turn signals. You MUST alter or relocate your turn signals.
There are many after market turn signals available for most bikes.

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Q: Why should I purchase an M4 exhaust system?

A: The simplest way to gain performance is with an aftermarket exhaust.
At M4 we take the time to make sure the performance gains you get are the best possible. We won’t feed you unrealistic or impossible numbers. You will get a real performance exhaust system, with horsepower and torque increases all thru the RPM range.

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Q: What should I buy? Full System, Slip-On or Bolt-On?

First, ask yourself, what is your goal as far as Performance, Weight, Sound and Looks?
A: Optimum Performance – Full system is the only way to go. Full systems are designed to get the most power and torque out of a stock motor with minimal adjustments.
A: Sound, Weight & Looks – A Slip-On or Bolt-On unit is what you want. With a Slip-On or Bolt-On unit you get a great look, save some weight and a sound that makes your motorcycle worth being seen and heard.
A: Slip-On unit replaces the muffler and mid section of the stock exhaust system. You retain the stock header.
A: Bolt-On unit replaces the stock muffler only. This applies to bikes where the stock exhaust system is in one piece.

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Q: How much does the M4 system weigh?

A: Full systems weigh in around 11 to 12 pounds. Weights vary depending on motorcycle.
A: Slip-On units – 6 to 8 pounds.
A: Bolt-On units – about 5 pounds.
A: Silencers – Stainless about 4.5 pounds – Carbon or Titanium about 4 pounds.

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Q: Do I need to re-jet or re-map?

A: It is not absolutely necessary to re-jet or re-map on every bike after installing a new M4 system. Most bikes will run fine if you don’t. In most cases, however, the ride and performance will be enhanced with optimal jetting and mapping.

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Q: What kind of gains can I expect?

A: Our full systems equal or outperform any other pipe on the market. Typically, we see a 6% to 8% horsepower gain over a bike’s stock system.
In cases where stock systems are already close to producing maximum power, a slip-on will usually provide an increase of 2 to 3 horsepower, and will give you the most bang for the buck.
Check out our dyno charts by clicking on the chart on your bike’s page.

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Q: What does a M4 exhaust sound like?

A: Well to be honest, most aftermarket systems sound pretty much the same. Some have a deep sound and some, after a few miles, have a raspy sound.
We feel our systems have a deep, mellow sound. Most systems are around 92 to 98db’s.
If you run your rpm up to the rev limiter the db’s may go as high as 100 to 102db’s.

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Q: What is the difference among the polished, carbon and titanium silencers?

A: Purely cosmetic and a little weight.

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Q: Are M4 exhaust systems street legal?

A: While some products manufactured by M4 may be legal for use on public roads under certain circumstances, M4 designs and sells exhaust systems for closed-course competition use only.

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Q: Do I have access to my oil filter and drain plug?

A: Yes.

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Q: What kind of warranty do I get with a M4 exhaust?

A: Due to the nature of racing exhaust systems, we can only warranty the material and workmanship for one year from date of purchase.

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Q: Are M4 silencers rebuildable?

A: Yes. Under norm usage you probably won’t need to for quite some time. We use a continuous roving packing material that won’t burn or blow out.

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Q: Can I buy replacement parts for my damaged M4 system?

A: Yes. Hopefully you won’t need replacement parts. If you do you can buy any part for any system. From springs, hanger straps, hanger brackets, collector units, mid-pipes, head pipes, silencer sleeves and repacking kits.

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