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Sooner City Machine Works and Fleming Engineering

A New Trike Product from a Proud Son of Fleming Trikes

by Ujjwal Dey



Jay Fleming is the son of Jack Fleming and therefore has the strong engineering influence in his life and work. He has announced a rough New Product – a reverse gearbox ready to make your trike work wonders on the road and on tour. Obviously, Jay can’t go into detail about the internals and how it operates, but we have a brief overview which should be sufficient for all but the most picky enthusiasts. There is a reference picture to get a judge of the size, with the dollar bill for understanding and visualizing your new trike gearbox.



Regarding the high performance parts, that is now Jay’s area of focus besides the gearbox. For the last 3 years, Jay had been building the Roadstercycle which his dad, Jack Fleming, built previously.


www.BikernetTrikes.com ran an article from Paul Garson back in 2012 http://trikes.bikernet.com/pages/roadstercycle_trikes.aspx



Jay’s roadster trike didn’t get built very fast, so only two were completed in the three years he labored on his family legacy. http://roadstercyclekits.com is the official website for those interested in these classic trikes. The 2016 Roadstercycle was the first one Jay built, the second was 80% complete when it was picked up and the customer finished building the custom trike. The frame, swingarm, suspension and all machined components were made in house at Fleming Engineering.


Beyond the Roadstercycle, Jay didn't build any parts for other bikes or trikes, but that's where he's heading with his custom engineering business.



This unique engineering product is shaft-in-shaft reverse gearbox. It’s perfect for your project that requires a concentric shaft reverse but with the input and output on the same side of the box, especially when adding reverse to any vehicle.


Website of Sooner City Machine Works: http://www.soonercity.com which is a new brand of Fleming Engineering LLC.



Dimensions (approx) 12.4" L x 6.0" W x 7.4" H

Weight: 23 Lbs

Forward Ratio: 1:1

Reverse Ratio: 2.14:1

Input Drive: Flat Flange (6) 5/16-24 threaded holes on a 2.50" BC

Output Drive: 1.25" - 19 Spline

Torque Limit: 120 Lb-Ft


$1500 plus Shipping ($40 UPS Ground in Continental US)



Options Available:

Input and Output Sprockets

Output Shaft Modifications: Shortening, keying, adding bearing boss

Outboard Bearing Support

Different Shifter Arm Options


Due to options available, gearboxes are not assembled prior to order. If all parts are in stock at time of order, allow 1-2 days for modifications (if necessary), assembly and shipment.


Fleming Engineering announced production of this new universal reversing gearbox. This gearbox is tailored to fit any motorcycle or similarly powered, chain driven vehicle. They proudly manufacture in the USA.


The most unique feature of this box is the “shaft-in-shaft” design where the splined output shaft is supported within the flanged input shaft. This feature allows for a smaller footprint than a non-planetary reverse, while also keeping the shafts on the same side of the box. This permits easier adaptation to fully-built vehicles that are currently without reverse. For certain cases, their gearbox may take the place of an intermediate jackshaft needed to offset sprockets for wider rear tires, swingarms or hubs.


The gearbox has a 6061-T6 aluminum case and high strength 4140 planetary gears and shafts. It measures approximately 12.4” long (with full length output shaft) x 6.0” wide x 7.4” high, and weighs 23 lbs without oil or options. Oil capacity is 6 FL OZ and requires full synthetic 10W30 oil. For those customers who would like to fit the gearbox into their digital design before fabrication, 2D drawings and 3D models are also available.



Many options and modifications are available, including but not limited to: input and output sprockets, auxiliary outboard bearing assembly, and output shaft shortening or keying.


Price: $1,500 USD plus shipping


For more info, please call 405-664-2244 or visit www.motorcyclereversegearbox.com           



4170 28TH AVE NW SUITE 155

NORMAN, OK 73069




The Roadstercycle is a three-wheeled reverse trike that looks and rides like nothing else on the market. It is the creation of Jack Fleming, who built the first Roadstercycle in a one-car garage in Redondo Beach, California circa 1996. Jack, who is always busy with some type of motorcycle or car-related project, offered the opportunity to his son Jay to take over the Roadstercycles who took it from there.


Think of Roadstercycle as a three-wheeled hot rod, reminiscent of the early hot rods with exposed engines - only the necessities and tons of character.


The least expensive route is to use a donor bike. The best donor bike to use for the standard kit is a '90-'97 Harley Softail. About 70% of the components can be swapped over to Roadstercycle kit. If you go this route, and you shop wisely for the remaining parts, a Roadstercycle could be built for about $15,000-$17,000. Using all brand new mid-grade parts would cost about $22,000-$25,000 including the price of the kit. Going all out could result in a total bill of $35,000-$50,000.


The current frame is designed to most efficiently use a Harley V-Twin engine, primary drive and transmission. Stock engine and trans mounts are strictly designed for the Evo engine with the Softail transmission. The frame can also be purchased without engine or trans mounts. The drive system is strictly chain drive and the Harley aftermarket has this covered. Japanese V-Twins or other American V-Twins may not be feasible unless the buyers designs a drive system on their own. The shaft drive from the V-Max and other cruiser bikes is not feasible on with this frame.



Roadstercycle’s low center of gravity and seating position makes it extremely stable.


LEGALITIES: What does it take to register a Roadstercycle?

Verify with your state's DMV but generally you'll need to provide a proof of purchase for the major items in the kit, such as the frame, engine and transmission. Roadstercycle Trike kits will come with a receipt documenting the parts included (including the frame serial number) and the frame will have a serial number stamped in the steering neck. If you are purchasing a new engine or transmission, either from Fleming Engineering or elsewhere, it should come with a Certificate of Origin. If you purchase a donor bike, you will need to provide the title or bill of sale to the DMV. If you buy a used engine or transmission and the seller can't provide a copy of the title, you will need to have a well-written receipt that lists the engine serial number or VIN stamped into the case.


RIDE ON and share with us your Trike Kit Adventures at wayfarer@bikernet.com or just drop us a note in the comments below.




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