Cycle News

VOL. 53 ISSUE 47 NOVEMBER 29, 2016 P33 package. Powering all four models is a liquid-cooled, DOHC, 12-valve, three-cylinder engine derived from the Triumph 675R, with the same 76mm bore but with the stroke lengthened from 49.6mm to 55mm to increase displace- ment to 749cc, and compression raised from 13.1:1 on the 675R to 13.5:1 on the standard Sprint models, and 13:8.1 on the R ver- sions. These and copious other mods have lifted power from 126 bhp at 11,900 rpm at the crank on the stock 675R, to a claimed 156 bhp at 14,200 revs at the rear wheel on the series production Sprints, and a hefty 180 bhp at the same revs on the R models. No torque figures are quoted. Spirit claims it's modi- fied the Triumph engine so ex- tensively that only the crankcase remains unchanged, but some commentators have speculated that these appear to be different on its engine than the current 675R's, and are, in fact, similar to those pictured in spy shots of Triumph's forthcoming next- generation Street Triple lineup, comprising a series of four mod- els that hasn't yet broken cover officially, but is known to have a capacity of 750-800cc. Given Tony Scott's close ties with the Triumph factory, it's quite conceivable that he's been supplied with components from this next generation engine by Triumph to form the basis of Sprint's new 750cc motor. Engine management is provided on the R-bikes by a fully pro- grammable MoTeC M130 ECU with different riding modes for road and track, adjustable trac- tion control, anti-wheelie and an electronic slipper clutch, with all parameters adjustable either via a laptop or via GPS and 4G cellular access. So not only can the bike's electronics be altered on the spot to individual choice, its ECU can also be accessed remotely by Spirit Motorcycles or any third party, permitting data analysis and adjustment of any available parameter. The full titanium 3-1 exhaust system on all four models ends on the R-variants in a heat-resistant lightweight Inconel race si- lencer developed by T3 Racing, whereas on the base models this is "just" a titanium-wrap can. The chassis in which this engine is housed is common to all four models, and is a spe- cially designed tubular steel trellis frame with the individual tubes brazed together rather than welded, supposedly to give improved feedback to the rider via controlled flex, and for ease of repair after a crash. Fully adjustable K-Tech suspension is fitted front and rear, with twin 320mm front discs and six- piston calipers from PFM, with a 220mm rear disc and two-pot caliper. The steering geometry is fully variable, with both ad- justable headstock and triple clamps to vary rake and trail. The twin-sided aluminum swingarm is handmade to MotoGP spec, says Spirit, and has an adjust- able pivot point, while the seat, subframe and all the bodywork is made from carbon fiber, as are the five-spoke Dymag wheels, the 5.5-inch rear carrying a 180/55-17 tire. Spirit's focus on saving weight has resulted in a claimed 308 pounds on the scale, includ- ing oil/water but no fuel in the 3.9-gallon tank for the fully faired GP Sport-R that's devoid of street equipment, against 319 pounds for the comparable but unfaired GP Street-R. Both the faired GP Sport and Naked GP Street street-legal models have the same claimed wet weight of 330 pounds fitted with lights and a horn etc., a notable saving on Triumph's quoted dry weight for the street legal 675R of 368 pounds. Prices for these high-tech high-end models are inevitably stratospheric, with the GP- Sport and GP-Street priced at $56,149, the GP-Sport R at $81,105 and the GP-Street R at an eye-watering $87,339, all with a seven-year warranty. It's unclear why the naked bike should be more costly, but all four variants are available as bespoke motorcycles built to individual spec in any color the customer chooses. Spirit states that full production will begin early in 2017, with deliveries of the first bikes in March. Alan Cathcart

• Cover
• Untitled