In 1990, the AMA introduced a roadracing class dubbed Supertwins, for Harley-Davidson 883 Sportster models. The class was intended to be an inexpensive avenue for riders to enter professional racing, either from club racing or from flat-track, where the majority of the USA’s roadracing champions started their careers. Race winners in the class included the Bostrom brothers, Aaron Yates and Jake Zemke, all of whom went on to win championships in the AMA’s more traditional classes. Unfortunately, creative interpretation of the rules became rampant and the class ran its course before the end of the decade. Fast forward 20 years, and the AMA is hoping to repeat the successful part of the class with its new Vance & Hines XR1200 class, which became part of the series midway through last year. While a media bike is available for members of the press to race at various rounds in the series, we decided to build and race our own bike, for a more in-depth look at the class. Harley-Davidson lent us an XR1200X model, and we made plans to race it in the Infineon round of the series.
Rules for the XR1200 class are very strict, both in order to keep costs low as well as to ensure fair competition. Most of the modifications are limited to those included in the Vance & Hines race kit for the bike, which includes almost everything needed to convert the sedate XR into something more track-worthy — an exhaust system and matching fuel controller, a 17-inch front wheel to replace the stock 18-incher, a steering damper, bodywork and mounts to relocate the stock oil cooler out of harm’s way. The kit retails for $3500, a bargain considering the individual parts add up to more than $5000. We obtained a kit and installed everything in a few days. All the parts are well-designed and nicely manufactured, typical of Vance & Hines products, and practically every detail has been addressed. The only finicky part of the installation was enlarging a hole in the lower triple clamp to mount the oil cooler bracket.
On the business side of the...
On the business side of the XR’s engine, you can see the 2-into-1-into-2 design of the Vance & Hines Widow exhaust pipe; the system has four bungs for O2 sensors, allowing the stock sensors to be retained in addition to the use of aftermarket sensors. The Öhlins steering damper and its related brackets are part of the Vance & Hines kit. The kit also includes the lines and brackets to relocate the oil cooler from the left side of the engine to behind the front number plate, a tidy installation that keeps the cooler safe in a crash.
The Gilles Tooling rearsets...
The Gilles Tooling rearsets are beautifully crafted and feature adjustable levers and footpegs. The shifter assembly permits both standard and race-pattern shifting. The right-side rearset did interfere slightly with the exhaust, requiring some trimming on the back part of the brake pedal.
The Vance & Hines Fuelpak...
The Vance & Hines Fuelpak (included in the race kit, $330 if purchased separately) allows fuel injection changes without the need for a laptop, and came pre-programmed to match the kit’s exhaust system.
This flat handlebar from Flanders...
This flat handlebar from Flanders is just one of a plethora of options available in Harley-Davidson one-inch handlebars; we opted for a medium-width, medium-bend drag bar. Spider grips intended for a standard 7⁄8-inch bar stretched on, while a G2 Ergonomics quarter-turn throttle is used. Note the stock master cylinder, mandated by the rules, and single Galfer brake line.
With the kit installed, we addressed the other areas open for modifications. For suspension, we turned to Fast Bike Industries, an Öhlins service center that has ties to the XR1200 series that has run in Europe for several seasons now. FBI provided us with a set of Öhlins shocks ($1274) with all the necessary adjustments — rebound and compression damping, preload and ride height. Our XR is the X model, which has a Showa Big Piston Fork assembly, and there were a couple of options for upgrading the fork. Many teams simply gut the internals and install well-proven cartridge kits, but we chose to replace the BPF pistons with aftermarket items, a cheaper alternative. The pistons are made by the Andreani Group, an Italian company that manufactures suspension components as well as provides trackside support for many of the Öhlins World Superbike teams. Cost for the fork modifications, including new springs, the pistons and assembly, came to $640.
Twisted Throttle sent us a...
Twisted Throttle sent us a full R&G protection package for the XR, which included front axle sliders ($51), rear axle sliders ($51) and these nifty Cotton-Reel swingarm spools ($250). The swingarm spools mounted with no drilling of the swingarm and allow you to remove the rear wheel while using a paddock stand. The company also offers a set of frame sliders to protect the oil cooler when in the standard position, but with that item moved safely behind the number plate we felt the sliders would be unnecessary.
The front fork (a Showa Big...
The front fork (a Showa Big Piston Fork on the X model XR1200) was modified by Fast Bike Industries with an Andreani Group piston kit (insets), a cheaper alternative to installing aftermarket cartridges. The front wheel is part of the Vance & Hines kit (a matching rear wheel is available but not allowed under the rules), as is the fender. The linear potentiometer is used with our Racepak data acquisition system during testing.
The front fork (a Showa Big...
The front fork (a Showa Big Piston Fork on the X model XR1200) was modified by Fast Bike Industries with an Andreani Group piston kit (insets), a cheaper alternative to installing aftermarket cartridges. The front wheel is part of the Vance & Hines kit (a matching rear wheel is available but not allowed under the rules), as is the fender. The linear potentiometer is used with our Racepak data acquisition system during testing.
The Öhlins shocks are a whopping...
The Öhlins shocks are a whopping 60mm longer than the OEM units, which helps in some ways (increased ground clearance, quicker steering) but hinders in others (decreased stability). The seat and its padding are included in the Vance & Hines kit.
Hand and foot controls are also allowable modifications, and we replaced the stock handlebar with a Flanders drag bar ($122). As you’d expect with something like handlebars for Harley-Davidsons, there are a multitude of choices for the XR1200 — Flanders manufacturers more than 1000 different models. We chose a flat bar with moderate width and sweep, something that would provide leverage to turn the heavy XR but not stick out in the wind too much. We added a quarter-turn throttle from G2 Ergonomics ($50) and used Spider M1 grips intended for off-road and motard use. The Harley’s one-inch handlebar limits options for both the throttle tube and grips; G2 makes a one-inch tube specifically for H-D models, while we were able to stretch the standard-sized Spider grips onto the bar. For foot controls, Gilles Tooling sent us a set of its Factor-X rearsets. These have adjustable footpegs, while the levers — also adjustable — pivot smoothly on ball bearings. It’s a bit tricky to switch the XR to race-pattern shifting, but the Gilles rearsets solve this nicely with a replacement clutch cover that houses a pivot for the shifter. Even with the thicker-than-stock engine cover, the Gilles parts trimmed more than 2.5 pounds in weight compared with the stock (steel!) parts. That quality does not come cheap; the rearsets retail for $822.
Brakes are ultra-important with a big, heavy bike, and we replaced the stock front brake lines with a three-line Superlight kit ($131) from Galfer USA. The XR’s front calipers are Nissin units and accept the same pads as many Honda models, so there are plenty of options available. We used Galfer’s HH Sintered Advanced Ceramic pads, which have fewer metallics than many OEM and aftermarket sintered pads, an important aspect as the XR class mandates stock rotors. The Galfer pads have a ceramic-coated backing plate that further helps to dissipate heat away from the pads and calipers, keeping the fluid cooler for better performance.
At about the time we were looking for someone to ride the XR for us, Bradley came aboard and made the perfect, er…guinea pig to ride the hog (we just had to work that in somehow). An initial shakedown at Buttonwillow Raceway was followed by a Pacific Track Time day at Infineon Raceway. Interestingly, because the track day was within 30 days of the AMA race there, we had to obtain permission from the AMA for Bradley to ride the bike at Infineon; a ruling disallows competitors to ride at a track within 30 days of an event, with certain exceptions made — one of which is for media. While the XR in standard trim is a solid platform and handles reasonably well, in race trim with the suspension significantly extended for ground clearance and the geometry accordingly changed, stability becomes a major issue. In our initial testing this was a limitation that suspension adjustments could mask to a certain extent but not cure.
The dyno run shown here for...
The dyno run shown here for the modified XR1200 is using the AMA’s spec fuel, Sunoco 260 GTX; the stock run was with premium unleaded.
That was not our only problem at the Infineon track day. The XR dropped a valve during the last on-track session, most likely due to over-exuberant downshifting on Bradley’s part. While rev limiters work fine during acceleration, there’s no stopping the engine spinning too fast if downshifts are made too early entering a corner. Luckily, we were able to drop the bike off at the Harley-Davidson fleet center to be repaired. Damage was limited to the top end on one cylinder, but a new piston, valves and cylinder head were still required. Lesson learned.
The Vance & Hines solid rear...
The Vance & Hines solid rear engine mounts replace the stock rubber pieces that tie the engine, frame and swingarm together, improving handling but also increasing vibration. You can see the new engine mount in place just behind the footpeg in the picture above.
The $175 Barnett clutch kit...
The $175 Barnett clutch kit for the XR1200 consists of tempered steel plates and carbon fiber friction plates with a segmented design to increase oil flow and extend clutch life. The company also offers a stiffer clutch spring, but the rules permit only the stock piece or an H-D replacement.
We used Maxima's Maxum4 Extra...
We used Maxima's Maxum4 Extra 15W-50 ($15.49 per liter) in both the primary case and crankcase of the SR. After every track day the bike got fresh crankcase oil and a new K&N filter (complete with wrench nut for easy removal and pre-drilled for safety wire), while the primary case was changed after every two days. Note that the oil filter is all-black, specifically for Harley applications.
Just before the AMA event at Infineon Raceway, Vance & Hines released a fix for the wobbly handling, in the form of solid rear engine mounts. The XR’s engine is completely rubber mounted to reduce vibration, but the rear mount also incorporates the swingarm pivot, making the frame/swingarm connection flexible enough that you can see movement with the bike even just idling at a standstill. With the solid nylon mounts installed, handling is significantly improved but vibration is increased as well. With the engine fixed and the engine mounts installed, we headed back to Buttonwillow for a TrackDaz track day to test everything and make any final adjustments. Handling was quite improved and we felt ready for the AMA race; there was just one last hitch in the form of a slipping clutch, which we remedied with a complete kit from Barnett. Testing completed, we headed off to Infineon Raceway for the AMA event. Tune in next issue for the results and full story.
Dunlop Sportmax D211 GP-A Spec Tires
As part of the AMA Pro Racing series, the Vance & Hines XR1200 class runs under the spec tire rules, meaning all bikes on the grid use the same Dunlop Sportmax D211 GP-A tires. With a 5.5-inch rear rim and the replacement Vance & Hines front wheel, the XR uses the same 120/70 front and 190/55 rear tires as the Daytona Sportbike and Supersport classes, which are available in three front and two rear compounds. The GP-As are manufactured in Dunlop’s Buffalo, NY plant, and use the company’s Jointless Band (JLB) and Multi-Tread construction; the rear tires are dual-compound, with a harder center portion for wear and a softer edge tread for grip. For the XR class specifically, the AMA and Dunlop select compounds for each track, meaning competitors all use even the same compound of tire. The spec tires are controlled through the use of stickers; competitors are given a set of stickers at the beginning of the weekend (four front and four rear in the XR class), and these must be applied to all tires used. Prior to each on-track session, AMA staff members check each bike to ensure the stickers are in place.
The Dunlops coped surprisingly well with the XR, considering its heft — the minimum weight for the XR class is 520 pounds compared with roughly 380 pounds for the other classes. Bradley reported good traction and neutral steering properties, and the tires showed good wear over the course of a track day, with only the rear showing signs of abuse at the end of a day. The Dunlop Sportmax D211 GP-A tires as used in the AMA cost $360 per set.