 HMF Yamaha Slip-On 4-Stroke Off-Road Exhausts |
||||||||||||
|
Product Description . Specifically designed for 4-stroke dirt bikes . Available in slip-ons for most MX, enduro and dual sport bikes . These mufflers are packed with guaranteed horsepower and torque . Ideal for racing, trail or street riding . 304 stainless steel inlets, T6061 aerospace grade aluminum canisters with solid construction TIG welded aluminum brackets for maximum durability . Heavy-duty stainless steel rivets, 2–piece billet end cap that accepts the exclusive HMF quick change low dB Quiet Core, All HMF offroad exhausts include a USFS spark arrester . Packed with RaceTex brand pillow packing for a deep rich tone . Factory direct customer service and tech support . All HMF products are made in the USA |
||||||||||||
|
|
Prices subject to change without prior notice. Please see Seller's website for actual shipping cost for ground or equivalent carrier within contiguous 48 US states including international orders. Click each site for more info regarding prices, discounts and other info. |
| Home | Compare Street Exhausts | Compare Off-Road Exhausts |
|
High Performance Aftermarket Exhaust HMF Engineering, Inc. was founded in 1997 by Hans Luenger in Cleveland, Ohio. Hans started the company by himself in his garage building private label aftermarket performance Ducati Motorcycle exhausts for Fast By Ferracci. As the workload increased, Hans hired three of his friends and bought a building in Brooklyn, Ohio in 1999 to help with the manufactoring process and diversify the product line. In addition to the Ducati exhausts, HMF began to produce it's own line of high performance aftermarket exhausts for the Honda RC 51 motorcycle and the Honda 400EX ATV. To better understand the market, Hans started racing motorcycles in 1999 and expanded the product line of sport and street motorcycle exhausts to better serve the sport he was competing in. After refinancing his house three times between 1999 and 2002 and selling his Corvette and FZR 1000 to keep the business alive, HMF reinvented itself once again by plunging into the ATV exhaust market in late 2002. The early HMF ATV exhausts were made using the technology and sophistication used in street bike exhausts. With the price starting so low, the public did not believe that the product was well built. Also, HMF had no name brand recognition. To boost rising sales, Hans teamed up with local Pro GNCC ATV racer John Gallager in 2003. Hans finished 3rd in his class and John finished 18th, but the real victory was the fact that thousands of racers noticed that the owner of an exhaust manufacturer was one of them. Sales consistantly increased through the year and by the 2004 race season Team HMF had grown from Hans #324 and John #18 to include five-time national champion Bill Ballance, and 11-time utility champion, Mike Penland. There was also a long list of devoted racers from almost every class in the series. After the top pro's signed on with HMF to begin production of a signature series exhaust line, national distribution was the next logical step. That solidified HMF today as a key player in the world of aftermarket exhausts. |
Making Your Motorcycle Exhaust System Work
If you insist on using drag pipes on your bike, there is something you can do to improve the low and mid range power produced by the engine. Even with the improvement listed here, the streetable engine power is not going to match power output of a good 2-1 or 2-2 exhaust system. Motorcycle Performance Guide does not recommend drag pipes or porker 2" pipes for serious street engines, but the performance fix listed here will improve the power of your drag pipes.
If it is loud, it must be fast? The first item to get modified or changed on most new Harley-Davidson motorcycles is the exhaust system. Getting the proper Harley sound always seems to require increasing the decibel level out the exhaust, with many riders installing drag pipes as the exhaust system for the proper sound. The rider often believes that by reducing back pressure in the exhaust system the engine will also increased power. This is wrong. As a resulting of changing a stock exhaust system to Drag Pipes, most engines promptly lose 5-10% of the power the engine produced.
By properly re-jetting the carburetor and adding a free flowing air cleaner to an engine with drag pipes, the maximum horsepower produced will improve over the stock engine. But there is a difference between usable power and maximum horsepower. The maximum horsepower of two engines may be similar, but the horsepower torque curves may be different. The area under the horsepower and torque curves defines the "power" the engine produces. The more area that is under the curve, the better the power.
A typical drag pipe produces a horsepower curve that initially rises very slow. As the RPMs start to rise above mid-range power, the curve begins to rise at increasing rate until maximum horsepower is achieved. Once RPMs have passed maximum horsepower, the curve drops of rapidly.
The horsepower curve of a typical 2-2 pipe like the Cycle Shack Slash Cuts produces a curve that may actually be closer to a straight line from low RPMs up through the rpm that maximum horsepower is produced. Once maximum horsepower is achieved, the curve drops at a relatively mild rate.
The horsepower curve of a typical 2-1 pipe like the SuperTrapp starts off slightly lower than the 2-2 pipe, but rises at a rapid rate in the mid rpm ranges. As the rpm range approaches maximum horsepower, the curve flattens out. Once maximum horsepower is achieved, the curve drops of rapidly.
If your taste in bike styling requires that drag pipe must be used, there is some hope to getting back some of that lost low to mid rpm power. Here is a poor boys trick that will make your drag pipes work much more effectively. This setup can actually be tuned to meet the performance needs of the bike.
If you insist on using drag pipes on your bike, there is something you can do to improve the low and mid range power produced by the engine. Even with the improvement listed here, the streetable engine power is not going to match power output of a good 2-1 or 2-2 exhaust system. Motorcycle Performance Guide does not recommend drag pipes or porker 2" pipes for serious street engines, but the performance fix listed here will improve the power of your drag pipes.
If it is loud, it must be fast? The first item to get modified or changed on most new Harley-Davidson motorcycles is the exhaust system. Getting the proper Harley sound always seems to require increasing the decibel level out the exhaust, with many riders installing drag pipes as the exhaust system for the proper sound. The rider often believes that by reducing back pressure in the exhaust system the engine will also increased power. This is wrong. As a resulting of changing a stock exhaust system to Drag Pipes, most engines promptly lose 5-10% of the power the engine produced.
By properly re-jetting the carburetor and adding a free flowing air cleaner to an engine with drag pipes, the maximum horsepower produced will improve over the stock engine. But there is a difference between usable power and maximum horsepower. The maximum horsepower of two engines may be similar, but the horsepower torque curves may be different. The area under the horsepower and torque curves defines the "power" the engine produces. The more area that is under the curve, the better the power.
A typical drag pipe produces a horsepower curve that initially rises very slow. As the RPMs start to rise above mid-range power, the curve begins to rise at increasing rate until maximum horsepower is achieved. Once RPMs have passed maximum horsepower, the curve drops of rapidly.
The horsepower curve of a typical 2-2 pipe like the Cycle Shack Slash Cuts produces a curve that may actually be closer to a straight line from low RPMs up through the rpm that maximum horsepower is produced. Once maximum horsepower is achieved, the curve drops at a relatively mild rate.
The horsepower curve of a typical 2-1 pipe like the SuperTrapp starts off slightly lower than the 2-2 pipe, but rises at a rapid rate in the mid rpm ranges. As the rpm range approaches maximum horsepower, the curve flattens out. Once maximum horsepower is achieved, the curve drops of rapidly.
If your taste in bike styling requires that drag pipe must be used, there is some hope to getting back some of that lost low to mid rpm power. Here is a poor boys trick that will make your drag pipes work much more effectively. This setup can actually be tuned to meet the performance needs of the bike.
