Typically, the average rider will need to repack their exhaust after about 40-50 hours of riding. This can vary, however, depending on the type of riding you do. More aggressive race machines are going to need to repack more often than the average trail rider. If you have the tools and experience to repack the exhaust yourself. Please note that our exhausts require an air rivet gun or an automotive-style riveter. A small hand riveter will not work for this.
Step 1: Using a marker, draw a line representing the clock position of the inlet and exhaust. Step 2: On the inlet side only, tap all the rivets until the stem drops. Step 3: On the inlet side only, drill out each rivet. Step 4: Using a rubber mallet, tap the exhaust shell to remove the inlet. Step 5: Using a 4mm allen key, loosen the allen screws on the end cap. Step 6: With the exhaust shell removed, discard of the old packing and wrap the new packing around the core. Step 7: When wrapping the packing around the core, make sure to make it as snug as possible. Step 8: Tuck the packing underneath the inlet.
Not all machines require tuning and we’ll tell you if it is needed or not. With modern fuel injection systems, they do not typically have the capability to compensate for the increased demand for fuel when an HMF exhaust is installed.
Company test and tune all the machines offer exhausts for. That way, can verify if a machine will run with a safe air-fuel ratio without a tuner. If a machine runs lean during testing, explore tuning options and try to develop easy solutions to fuel tuning to complement our exhaust.
Read the tuning description for your machine to determine whether recommend fuel tuning or not. If your machine is marked "Fuel Tuning Required", then your machine must be tuned with an HMF exhaust system. Failure to tune the engine can cause excessive damage to the exhaust system and engine while voiding the warranty on your exhaust and possibly on your machine.
The first step when installing the Optimizer is to connect it to a good ground source. This can be a good part of the chassis or the negative battery terminal. Failure to do so can result in damage to the Optimizer.
Locate the Fuel Injector on the Throttle Body, which is between the Cylinder Head and Air Intake.
Unplug the OEM Connector from the Fuel Injector.
Connect the Female Optimizer Connector to the Fuel Injector.
Connect the Male Optimizer Connector to the OEM Fuel Injection Wire Harness.
Repeat for all injectors.
Mount the Optimizer in a safe area where you have easy access to it for on site tuning.
Run the HMF Optimizer wires so they’re clear of any moving or hot parts.
It's an often misconception that a fuel-injected engine will automatically tune itself when an aftermarket part is added. This is actually not the case. When adding an aftermarket part that directly affects the engine, retuning or remapping will be required.
The HMF Optimizer will change the signal to the fuel injector to compensate for added aftermarket parts. It is a piggy-back fuel controller that plugs directly into the vehicle wiring harness and stays connected so long as it is needed. It's small, water-resistant, and mounts just about anywhere.
What it can do is compensate (to a certain point) for changes in air density such as temperature, humidity, and elevation. Since the computer cannot see intake air volume or monitor the oxygen content in the exhaust, it does not know additional fuel is needed. That's where the HMF Optimizer will take over.
Each and every Optimizer has a different map that's been programmed for that specific machine with Company HMF exhaust systems. After Company have completed exhaust development on a new machine, Company dyno for horsepower testing and fuel tuning. Air to Fuel ratio (AFR) is measured by a wide band Oxygen sensor placed in the head pipe of the exhaust. If the AFR is rich (too much fuel) or lean (not enough fuel) Company use the Optimizer tuning software to build a custom fuel map that meets the needs of the particular model that Company are working with. The software lets us add fuel based on RPM, load or, a ratio of both. When it is all said and done, Company have an affordable fuel controller with a map created specifically for the vehicle Company are working with. The problem is no two engines are the same, and most of the time you aren't going to stop with an exhaust.
You will likely add a free-flowing air filter, maybe a cam or headwork, etc. All of these will change the fuel demand. That's why Company leave you, the master tuner, with the ability to make tweaks to the fuel map. The best way to be sure your Optimizer is set perfect for your individual machine is with a wideband oxygen sensor. If you do not have access or are not familiar with this equipment, it is best to take your machine to an experienced tuner.
There are 3 modes that will allow you to increase or decrease fuel percentage from the original fuel map.
Mode 1 - Green: This controls fuel delivery at lower throttle positions and RPM Mode 2 - Yellow: This controls fuel delivery at mid-range throttle input and RPM Mode 3 - Red: This controls fuel delivery in higher throttle positions and RPM
There are two (in some cases three) more modes that are often misunderstood.
Mode 4 - Green and Blue typically will control the accelerator pump feature found on select models only. Lower on the number scale will give you less fuel when you stab the throttle. Higher on the number scale will give you more fuel when you stab the throttle.
Mode 5 - Yellow and Blue typically controls the timing of your yellow mode. Lower on the number scale in this mode will bring your yellow mode in sooner. Higher on the number scale will bring your yellow mode in later.
Mode 6 - Red and Blue typically control the timing of your red mode. Lower on the number scale in this mode will bring your red mode in sooner. Higher on the number scale will bring your red mode in later.
If you encounter a drivability problem like a stumble, pop, or misfire, take a look at the Optimizer display when the problem occurs. If the lights are yellow when the problem occurs, try making an adjustment to the yellow mode and see if the problem goes away. If the lights are red when the problem occurs, try making an adjustment to the red mode and see if the problem goes away.
Make all mode adjustments with the engine idling. To increase fuel for any of these modes push the plus button. (While in that particular mode) The L.E.D. lights will move to higher numbers. To decrease fuel, push the minus button. The L.E.D. lights will move to lower numbers.
The quiet core insert is designed to install in a number of HMF exhaust series and will reduce the sound output of the exhaust anywhere from 3-6 dB depending on the machine and the exhaust series.
Installation is just as simple as installing the spark arrestor that comes with the HMF exhaust with the insert sitting between the end cap and the end cap base with most of the insert extending into the exhaust’s core.
The purpose of the spark arrestor is to keep hot debris from exiting the exhaust which can potentially harm the environment. They are easy to install, simply unbolt the end cap and place the spark arrestor in the recess built into the end of the silencer then reinstall the end cap. A spark arrestor is provided with every HMF exhaust.
Spark Arrestor Installation
A common question is, “Will the spark arrestor decrease the power of the machine when installed?” The simple answer is no. In no way will the spark arrestor ever create enough restriction in the exhaust system that it will decrease horsepower or torque. Unless the spark arrestor is blocked or clogged with debris there is no appreciable flow restriction.
Spark Arrestor Maintenance Yes, from time to time you will need to inspect and clean the spark arrestor. If the spark arrestor is plugged with carbon deposits from the engine simply remove it, soak it in a solvent such as oven cleaner for a few minutes, then finish the cleaning process with wire brush, finish by drying it and reinstall. If the spark arrestor is plugged with dirt or mud the process is even easier. Remove it, clean it out with water and remove any stubborn bits with a wire brush, rinse, dry, and install.
The torque range modifier is designed to broaden the available torque range of the machine which can help for better “hook up” and acceleration. It will not alter peak horsepower or top speed in any way. The torque range modifier is not a sound dampening device and will not alter the sound levels.
Often times a customer will want to run a quiet core insert and is also required by local law to have an exhaust with a spark arrestor. Is this possible with an HMF exhaust? Yes, of course! In fact, if a quiet core insert is used, it is recommended to use the spark arrestor as well to reduce the chance of the quiet core insert rattling inside the exhaust. The same applies when installing a torque range modifier, it is recommended to use a spark arrestor. The one thing that cannot be done is the combination of a quiet core insert and torque range modifier.
HMF exhausts are available in a variety of shapes, series, lengths, etc. What works for one machine may not work for another. During our R&D process the team will test different configurations and then determine what will work best with a particular machine. The information below goes over the different system types Company offer and the explains the features of each system type.
Slip-On Systems By far the most popular, easiest, and simplest to install system, our slip-on systems are designed to be a direct replacement for a vehicle's original silencer. Typically this will be a one piece silencer with an inlet that matches up to the vehicle's original headpipe(s). Slip-on systems can either be a single silencer setup or duals depending on the machine.
Full Systems A full system is going to replace the entire stock exhaust on a vehicle. This is where the R&D team has the freedom to redesign every aspect of the exhaust in order to get the best possible results. Some of the changes Company will make to an exhaust system will include the diameter of the exhaust pipe, the routing around components, headpipe length, and anything else Company can dream up. As with slip-on systems, our full systems may either be a single silencer setup or duals depending on the machine.
3/4 Systems Company 3/4 systems are unique and fall between a slip-on system and a full system. With some machines, there are design restrictions or limited benefits to creating a full system. It is in these cases where a 3/4 system will come in to play. The basic design of Company 3/4 systems will vary quite a bit but will generally include new HMF silencers, and then either a replacement mid-pipe or one of the head pipes on a vehicle that has multiple cylinders. A 3/4 system is also going to typically be much easier to install than a full system, and that is also a consideration when designing these unique exhaust systems.
Big Core Systems
The Big Core Systems developed by HMF are typically going to be for high horsepower, reduced weight racing applications. Machines like the Polaris RZR Turbo and Can-Am Maverick X3can benefit greatly from a short, high-flow system. These systems will have oversized cores in the silencer to minimize any restriction to flow in the exhaust system and provide the potential to make big power increases.
Mini Can Systems Some machines simply just don't need a full size silencer. Company Mini Can systems are a perfect, lightweight replacement for big, bulky, restrictive factory exhaust systems. From youth quads like the Yamaha Raptor 90 to mini-motorcycles like the Kawasaki Z125 Pro HMF has developed a number of these Mini Can systems with the same level of quality and craftsmanship you would expect from HMF.
With the incredible level of diversity in the Powersports industry, HMF is continuously developing new exhaust systems and equipment as well as updaing existing designs to stay ahead of the competition.
The answer to that question depends on your machine, how you ride, where you ride, etc. Most machines HMF offers exhaust for will not include every series created. You wouldn’t put an exhaust snorkel on a 450 sport quad would you? Company recommend you read up on Company different exhaust series here and check out what is available for your machine. A quick summary of each system can be found below. If you have further questions or are looking for recommendations give us a call or email and Company will do what Company can to help you.
Performance Series
Lighweight, Aluminum silencer Customizable with multiple colors and endaps, Blackout available Broad, even power gains
Competition Series
Similar to the Performance series in construction, but with a special core designed for closed course competition Focused on mid-range power gains with the HMF TriMax core Designed to work best with high revving sport ATVs
Titan Series
Larger 5" diameter all stainless steel silencer construction Extremely durable, requires very little maintenance 2 different inner core designs | XL: Loud | QS: Quiet
Absolutely! When we develop exhaust systems we have to look at a lot of different variables including head pipe diameter, exhaust system total length, backpressure, resonance, space restrictions, heat management, etc. From there we take the stock exhaust off the machine and study that to see where we can improve upon it. With modern machines and ever increasing horsepower numbers powersports manufacturers spend a lot of time and money making a cost effective exhaust that balances power, sound, durability, and emissions. At HMF if we make a slip on and a full system our credo is that we have to make more power with a full system. Sometimes that means that we can only offer a full system on some machines because a slip on just didn’t produce a power increase.
Turns out, most of the luster of your exhaust lies in a small green pad with a rough surface; Scotch Brite®. This little green monster can be used to take off a ton of dirt and grime from your exhaust system, and leaves it a nice revived shine.
Of course, this only works on the brushed aluminum and stainless steel cans. Don't go takin' this Scotch Brite® to work on your beautifully coated Yellow and Black exhaust shells, or the Blackout head pipe.
So let's get this straight. I can use a rope or long piece of wire to help me with the installation of my HMF exhaust system?
The answer is yes.
Many of our HMF exhaust systems require springs to help secure the inlet and exhaust to the stock/HMF head pipe. Using a long piece of wire or string to install the springs is the way to go.
Simply slip the long piece of wire or rope through the end of the spring and simply pull it over the mounting tabs. This a very safe, and effective to properly install your system, with little to no cost.
Many riders are modifying their machines for deep mud riding as the popularity of the sport increases. When getting down and dirty, the first modification for most quads are snorkels on the intake, exhaust and transmission.
It is important to remeber that other modifications are typically neccessary when you're making intake and exhaust snorkel modificaitons.
Intake Snorkels
When you're installing a snorkel on the intake system, keep in mind you'll typically be required to tune your engine. When choosing a snorkel, the larger diameter intake, the better. Small diameter intakes can choke the engine which would require jetting down.
Exhaust Snorkels
HMF has created a series specifically with an exhaust snorkel, Company appropriately have named it the the Swamp Series. The Titan Series is the basis for the Swamp Series minus the exhaust snorkel. Company built these cans out of resistant stainless steel, with specially designed packing that is extremely durable. The exhaust's end cap allows a snorkel system to be securely attached to the exhaust itself. Once the adapter has been installed, various bends and attachments are available for a complete system. If you already have a Titan Series exhaust for your machine and want to add an exhaust snorkel check out Company Snorkels section, there are some pre-configured setups for specific machines as well as a universal kit.
Does the snorkel work with any other HMF series?
No. Other HMF exhaust series were not designed to be used with a snorkel. The diameter of Company other series is much smaller, and the internal was not built to withstand the pressure the water can create. If you are going to build a snorkel for any of your HMF exhaust series systems, you will be voiding your warranty. The packing on any other series will wear out at a faster rate than normal when used with a snorkel due or if water enters the silencer. Repack services will need to be performed more often in these cases.
While some companies will say that installing a slip-on does not require tuning, at HMF this is rarely the case. Most of the restriction in an exhaust system lies in the muffler. By changing this you are making the biggest change to the potential flow through the exhaust system.
Some larger UTV/SXS vehicles now include catalytic converters which may be integrated into the muffler or elsewhere in the exhaust system. Catalytic converters create a massive restriction to exhaust flow and removing one can definitely make a huge difference to exhaust flow and therefore tuning requirements.
Because the HMF exhaust systems increase the potential air flow through your engine that must be compensated for with more fuel. In order to maintain a safe air-fuel ratio when flowing more air through an engine the fuel flow has to increase roughly the same percent as the air flow. If your machine develops 10-15% more power it will need at least that much more fuel.