I fell in love with the Quantum Liberty Cruiser and am astounded by what American Quantum packed into this bike for under $20,000. This bike is designed engineered to be an affordable custom bike, being built almost entirely of aftermarket upgrades for the Harley Davidson label, bought in quantity so that the economy of quantity buying could be passed on to the buyers. During American Quantum's original expansion their owners had even worked out an arrangement with Wackenhut, contracting labor from the Florida prison system for parts polishing and for some of the fiberglass work. Under its original ownership, American Quantum was a study in best practices.

I've listed and linked to the web sites of the manufacturers whose parts were used in the production of this bike to make it easier for you to replace or upgrade damaged or worn parts. Additionally, I've started a Q&A page where I'll post questions that owners have had along with the answers I've received from reliable sources. If you like, I'll also begin a forum where I'll post helpful comments from people who've owned and have serviced American Quantum Motorcycles.

After using Kenny Boyce frames for the first run, the Quantum engineers designed their own FXR Pro Street frame and had Kraft/Tech build it. The welds are beautifully executed and their finish work is superb. Then Quantum engaged Sumax to cover it with an exquisite opalescent pearl white powder coating. The swing arm is chromed to make cleaning easy and to add just a bit of flash to the bike, giving it a nice balance of color and chrome.

The front end and shocks, manufactured by American Suspension, were designed by Vince Costa who races in the International Hot Rod Association and whose fork assemblies and suspensions dominate the AMA racing circuit. The 63mm inverted forks provide a wide, stable stance and lateral rigidity and minimize unsprung weight at the front end for more compliant ground tracking on bumpy roads. The rear suspension is controlled by American Suspension adjustable gas shocks.

The matched wheels and pulleys, manufactured by Sturgis Wheels, are strong, light, easy to keep clean and they're gorgeous, and the extra wide Avon tires feel a lot surer–footed than the older, narrower wheel/tire designs. There's a wide, sticky Venom–X MT90B16 on the front and a whopping 6.3" wide 160/80B16 81H on the back.

Manufactured by Thunder Heart Performance Corp., both front and rear brakes (RSB2008-smth) are single–disk setups with four–piston calipers. The Dash/Console (RSE4400), fed information by the transmission speedometer sensor (RSE41000) is informative and easy to read. The electronics are all held together by Thunder Heart's wiring harness (RSE4200) whose Electronic Harness Controller will show you if there are shorts, breaks or overloads in the kill switch, high/low beam, brake light, horn, turn switches, oil and neutral indicators, each turn lamp and auxiliary power circuits. The manuals can be downloaded from Thunder Heart's web site and are well–written and easy to read. The forward controls (RSC3265) and passenger pegs (RSC1650) are clean and sure–footed.

The flame–design point cover (which mirrors the flame motif on the tanks and fenders) from CAT, LLC was such a sweet little detail  that it was almost too good to be true. I guess that I have the folks at Performance Cycle to thank for that touch.

The stainless steel braided brake and oil lines and the fuel lines were provided by Russell Performance Products. The braiding on the brake lines not only minimizes wear and tear of the lines, but also virtually eliminates expansion of the lines, delivering all of the force of the brakes to the pads for stopping, and all of the feel of the brakes back through the pedal to give the rider maximum control. Couple this with Russell's ample 11" Satin Finish Brake Rotors (Model # 47000 on the front and Model # 47005 on the rear) and you have dependable stopping power with the ability to dissipate heat effectively on the long downhills and on demanding switchbacks.

The 5 gallon stretched gas tanks are beautifully finished. Their downward curve adds a grace to the powerful line of the bike while positioning the aft end of the tanks out of the way of the rider's legs. The trailing ends are swallow–tailed to fit very nicely around the nose of the seat. Their contents feed through a Pingel fuel valve that looks great and operates as smooth as glass.

The Mikuni HSR42 is a pretty sophisticated and reliable carburetor. It sports separate circuits for “the choke system, the idle system, the main system and the accelerator pump system. Each of these systems has its major effects in a different throttle range. While there may be some overlap, each system can generally be treated as though it is completely responsible for its range of throttle settings. Three of the systems have replaceable components that allow fine–tuning should the need arise." (Quoted from the Mikuni Tuning Manual for HSR42/45 Carburetors, Rev. 5/10/00). The "Complete Kit" from Mikuni contains a  high–flow filter from K&N (Model F02C8) specially designed for the high throughput of the Big Twin Evo engines. The chrome cap under the left gas tank covers a removable plug in the plenum allowing installation of a 2nd carburetor. This second carburetor acts as a vacuum secondary resulting in a 10% increase in power.

The late Jim Feuling and Feuling Advanced Technologies, Inc. developed the 4valve heads (as well as the high–flow high efficiency combustion chambers for the Mercedes race team, the 3 cylinder advancement of the 45 VTwin engine and low–drag helmets for Bell, used for high–speed open–cockpit testing) as seen in American Quantum's 4/30/99 SEC filing.  Jeff Starke, founder of American Quantum Cycles, received rights to the patents for the 4-Valve Heads directly from Jim. Jeff has continued to develop the heads and valve system for improved performance and reliability. The 4–valve heads, which fit Evo, Sportster, and Buell engines, and replacement parts are available at directly from Jeff. Here's a link to the documentation for the older style 4-Valve heads, showing how to install them. Documentation for specifications and installation instructions for the later refinements will be posted as it becomes available.

Here is a brief list of modifications that have been made to the 4-Valve heads and which have been incorporated into the heads, which are now available to you:

Started by a Spyke SPS90-C Super Torque starter, the heart of the power plant is a rubber–mounted 96 cu. in. long block kit (31–9219) from S&S Cycle, Inc. The kit includes the crankcase, flywheels, etc. Look at the link for the list of parts and look in the journals for reviews of their product quality and reliability. The camshaft is a Crane Fireball H-310.

Once the fuel–air mixture is drawn through the 42mm Mikuni carburetor past the 4–valve Feuling heads into the spacious cylinders and is compressed into less than 1/10th of its original volume, the CompuFire model #20600AQ single–fire (dual–fire and dual–plug capable) system delivers its charge to the Crane Cams coil (8-3001) through the Crane plug wires to  the top of the S&S hemi–head sidewinder pistons and, to quote Quantum's web site, the bike is off like a prom dress. Compu–Fire's stock ignition is the model 20600 and the AQ model has special advance curves programmed to take advantage of the performance modifications made to the engine. Compu–Fire was also called upon to provide the (model #55120) voltage regulator. They've also provided the charging system, the model 55530 stator and model 55650 rotor.

The engine's power is delivered through the clutch assembly. The Harley–Davidson OEM basket was manufactured by Chrome Specialties, Inc. The clutch is a Rivera ProClutch (PC1298C) and the Kevlar plates furnished by Alto help to make this one of the best aftermarket clutches on the market, able to handle 150+ horsepower while maintaining a light lever pull (provided you use the recommended ATF and not gear oil in the chain case. The primary drive, a self–adjusting chain, delivers the power, in its turn, into the transmission case manufactured by Delkron, the industry standard for accuracy, strength and reliability. Inside the TRV2 are bearings manufactured by Timken and gears designed and machined by Andrews Products, Inc.

The Bub two-to-one exhaust system was developed to meet EPA requirements and does a nice job of scavenging the spent gasses from the cylinder at low revs, letting more fresh air in for the next burn cycle and raising the horsepower and torque.  I'd love to see what would happen if I used the Feuling-developed anti-reversionary exhaust system that Jeff Starke recommends. He knows these modifications better than anyone else and has seen the results on a dynamometer.

The seat was manufactured by High End Products, Inc. Their workmanship is good, the Python seat looks great and their closed cell foam padding is more comfortable than the stock Harley–Davidson seat. Where I could last only about 45 minutes in the saddle of my old stock 1995 Sportster 1200, I don't feel the fatigue nearly as quickly with the Python seat (although I'd like to try out some of the seats that iron butt riders use). To top it all off, Performance Cycle provided a touring seat and a back rest so that my sweetheart can be comfortable in the copilot seat. They've also rigged it so that it takes less than 5 minutes to switch from the sleeker solo setup to the touring seat and rest.

I offer this site as a reference spot for Quantum owners and would be glad to try to help you find answers to questions about this bike.

I took some pictures of the bike on October 3, 2017. Click here to see them.

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