MASTERLIST OF 2-CYCLE SERVICES AND PRICES

Forward Motion offers the widest variety of performance machining services in the powersports industry. The categories are general machining, porting, and plating with porting.

GENERAL MACHINING SERVICES

CYLINDER BASE and HEAD MACHINING 50-112cc $75 125cc+ $100

Cylinder head and cylinder bases can be turned and machined to produce a powerband that is better for beginners and trail-riders. The technical reasoning is that this modification serves to retard the port timing and increase the squish velocity produced in the cylinder head. If you just want more low end and don’t want to spend a fortune, this is the best mod that will give you the biggest bang for your buck!

CYLINDER HEAD MODS $35

This service includes all machining modifications per situation and application. Services include gasket surfacing, turning, clearance-machining for big bores and or strokers, flat-top piston conversions as well as hemi and conical dome shaping, lowering compression for low octane pump gas with ethanol, raising compression for high altitude. Optional services include TIG-welding, o-ring groove cutting, plug-hole turning and threading, and decompressor installation. Call for a quote based on the year, make, and model of your bike and the application.

POWERVALVE SERVICE 50-144cc $30 200cc+ $50

Powervalves are built into the cylinder around the exhaust port. They’re supposed to make the exhaust port bigger when you twist the throttle open. Powervalves are complicated mechanisms prone to failure. We offer a service to clean, inspect, and adjust the powervalves. This service comes standard with all porting, super-stock, and big bore packages.

CRANKCASE SERVICES $50-$150

Crankcases can be repaired with welding and resurfacing. Services like porting and polishing to smooth transitions to the transfer ports, and clearance mods for big bores and stroker cranks.

BORING and HONING for cast iron-lined cylinders $65

This service includes cleaning, boring, diamond-honing, port chamfering, exhaust bridge relieving and polishing. We offer Wiseco, Wossner, Pro-X, JE, Athena, Magnum, and Vertex piston kits as well as Cometic gasket kits.

WHAT IS CYLINDER PORTING?

Porting is a metal machining operation designed to enhance the powerband characteristics of an engine, especially with aftermarket bolt-on accessories like exhaust and intake products, stroker crankshafts, big bore kits, and ignitions. Forward Motion offers all-inclusive porting packages for all types of 2-stroke dirt bikes, ATVs, snowmobiles, and shifter karts. Eric Gorr does all the porting himself and has worked with porting tools since the early 1970s and ported over 70,000 cylinders. More than all the other popular hop-up shops combined.

Eric is well trained in the use of the latest software programs that the motorcycle manufacturers and racing teams use, like the ones available from the late Professor Gordon Blair www.professorblairandassociates.com these programs are the standard in state-of-the-art design of championship winning motorcycle engines and recognized by the Society of Automotive Engines www.sae.org and used by the world’s top universities. Forward Motion is a Gold sponsor of the University of Wisconsin (Madison) Formula SAE Team. www.uwracing.com

Eric uses modern computer design software to do the number crunching needed to reconfigure cylinder ports to enhance the powerband to the way you want it to be. Eric is the only tuner in motorcycle racing with two US Patents, a published SAE technical paper, and six motorcycle books to his credit. Eric made his reputation on porting and does all the work his self, no illegal aliens, space aliens, or third world slave labor. It’s just middle-aged fart-knocker labor from one of the oldest and most experienced tuners in the world, whom still actually rides motocross, dirt track, trials, and supermoto.

Cylinder porting can improve the reliability and ride-ability of your bike, and all the top end parts need to be modified as a set like in these package deals.

2-STROKE PORTING PACKAGES

All 2-stroke porting packages include complete porting, not the fake fluffy crap that most In and Out Porting and big time SoCal hop up shops offer. All of these porting packages include the following: disassembly and cleaning of all the top end components, complete porting and polishing, cylinder head machining, base machining, diamond honing, baking soda blasting, powervalve service or epoxy-filling, powervalve assembly and timing of applicable models.

DIRT BIKE PORTING

MINIS

65-112cc $185

MX LITES

125-200cc $200

Complete porting and machining work performed to all the ports, base and head machining on most models. Powervalve service on applicable models. Diamond honing especially for Vertex and ProX alpha oversizes. Three powerband choices of more low to mid-range, more mid to top end or a smoother broader powerband, plus all of the services listed above.

OPEN CLASS

250-550cc $225

SPECIAL PORTING PACKAGES

HONDA CR500 PORTING $225

In the glory years of the 500cc Grand Prixs in Europe throughout the mid-1980s and 90s, Eric’s CR500 tuned Hondas were the boss ride. Legends like Jorgen Nilsson and Leif Persson of Sweden, Rodney Cuff, Rob Herring and Mark Eastwood of England, Jacky Vimond of France, and Peter Dirkx of Belgium owned the first turn at the GPs and turned the ultra-expensive HRC Factory bikes into insignificant bridesmaids.

In modern days the Service Honda CR500AF’s have reveled in the praise of American dirt bike magazines for the last 12 years. Eric offers porting through Service Honda and in 2006 Dirt Rider magazine ran an Internet Bike Shootout and www dirtrider.net teamed with Service Honda. DR’s test riders demanded that a manual clutch be installed on the bike because the powerband was so smooth they thought the Rekluse auto clutch was slipping. The testers praised the porting and powerband with the smooth powerband with extra revs on top. You can choose the type of powerband and fuel type. Eric builds a lot of CR500s for mx, enduro, desert, hill-climb, dirt track, technical mountain climbing at altitude, and ice-supermoto and oval racing.

The porting package on the CR500 includes cylinder porting, base machining, head work, manifold matching and polishing, epoxy porting, soda-blast cleaning, and diamond honing to the next oversize, if needed. Additional parts options include your choice of pistons from a forged Wiseco and Wossner forged piston kits as well as cast pistons like Vertex, Athena, OE Honda, and Pro-X for about $180. Cometic stainless steel gaskets $35, and top end bearings $20 The CR500 porting package with top end parts is $475.

VINTAGE PORTING $185

Eric raced motocross since 4-strokes were popular the first time (1970) with his Ducati 250 Scrambler. Working as a mechanic and tuner since 1971, Eric has accumulated porting specs from all sorts of sources like factory racing directives, practical experience, and the use of modeling software. You might say he’s a bit of a vintage freak and sympathetic to vintage meisters like yourselves.

Eric works on all brands of Japanese and European motocross bikes. If you are a vintage freak and have historical specifications that you would like machined to a cylinder, Eric will cater to your needs. He has also ported cylinders to exact historical factory specifications from Harley Davidson Racing directives from Dick O’Brien to Team Green to Yamaha Wrench Report and even Swedish-language blue-prints from Husqvarna. If you have an antique cylinder with a cast-iron sleeve and you want to preserve the bore size, we can nickel-composite plate the bore to preserve the bore size.

YAMAHA PORTING for Vintage YZ465, 490, & WR500 $185

Starting with the first YZ250A in 1974, Eric tuned and raced Yzs for years. In 1980 he teamed with Troy Bradshaw and hit the nationals. Troy pulled some awesome starts and great placings in the Trans-Am series and soon Team Keystone Yamaha’s sported Eric’s Flow-Ported YZ cylinders. In 1981 Keystone’s Jeff Hicks placed second to Danny “Magoo” Chandler in the Trans Am series. Magoo was also sponsored by Eric on a RM125 in the nationals that year. That series launched Jeff Hick’s career as a factory sponsored Team Yamaha rider and Magoo as one of the most fabled factory Honda riders of the 20th century.

In 1984 Troy Bradshaw made history at Loretta Lynn’s by winning the Open Class championship besting the factory sponsored riders from Yamaha and Kawasaki. The porting, cylinder head and carb tuning specs developed in that era can help your YZ run much better and be less sensitive to fuel quality and jetting.

Our comprehensive service package includes center-mandrel machining of all the gasket surfaces of the cylinder and head, complete porting and polishing of the exhaust port, epoxy-filling of casting flaws on applicable models, intake boost-ports bored and polished, head modifications, and diamond-honing.

SHIFTER KARTS $185

What a sick twisted form of racing! G-Forces that will give you kidney failure and the ability to cut lap times faster than an Indy car! Eric offers a wide range of services ranging from cloning old cylinders to setting up specs for mx class and IC engines and even clay-oval outlaw racing. Eric specializes in CR125s and also handles all the IC engines like the Pavesi, TM, and CRC.

Eric performs cylinder porting and matching head mods, along with diamond honing of the bore for only $185.

CLONE PORTING $185

Racers are a superstitious bunch and if you have a cylinder that is trashed and you need a new one cloned to the old one for good luck sake, Eric can fulfill your wish. Send the old cylinder and a new one, blueprints or drawings are OK too if the old cylinder is destroyed.

ATV PORTING & HEAD MODS $185

We’re crazy about 2-stroke ATVs, modern and vintage. We offer services to maintain them, big-bore, re-sleeve to stock or mega-bores, clone to obsolete specs or non-current tuners specs whom have passed away or their companies have gone out of business, as well as fixing the lame tuning of Chineese made aftermarket cloned cylinders that make big promises and deliver less than inspiring results.

SNOWMOBILE PORTING $150 each PORTING & PLATING $335

Eric did his apprenticeship in 1975 with Gordon Rudolf of Rudolf Engineering in Northbrook Illinois. Gordy invented the first 3-cylinder Polaris 500 Centurion, the first independent front suspension snowmobile for oval racing in 1976, the first long travel snocross machine in 1981. Gordy’s workshop was like the unofficial Skunk-Works for Polaris in the 1970s. It was truly an apprenticeship to genius and a witness to the history with snowmobiling’s most colorful character during the dawn and development of the sport’s future path.

Now all of that benefit of tuning knowledge is available to you for your snowmobiling needs. Whether you race vintage oval, snocross, lake race, hill-climb in Yellowstone or run the power lines in the UP, we can help you fulfill your performance needs with performance machining services ranging from plating, super-stock, mod, and big bore conversions using Wiseco big bore piston kits.

PLATING WITH PORTING MODS

The foundation of our big bore kits is Millennium Technologies’ nickel-composite-plating. It’s an electrolytic process that plates a composite of nickel and silicon-carbide particles that comprise the cylinder bore. It’s similar to the original OE coating but better, because we layer the plating on thicker and its harder to increase the bore’s life. Some companies install gray-iron sleeves for their big bore kits so they can advertise a cheap price. Kits such as these do not include porting and the sleeves have a limited life. Once they wear out, the whole cylinder is junk, along with your investment in a big bore cylinder.

We do things the right way with porting, head and powervalve mods, and MT’s plating. Here are the prices for plating and porting together, based on displacement.