Slip-On Performance

Speed’s Secrets, July 2009

Everyone’s watching the wallet a little closer these days, looking for that maximum bang for the buck. It’s out there, too, especially when it comes to a nice Stage 1 tune-up for a Harley. Stage 1, of course, includes a good, free-flowing intake and exhaust, coupled with a fuel-delivery re-map for the injected bikes and re-jetting for the carbureted models. All this is just about mandatory for any factory Harley-Davidson, too. It’ll bump up the horsepower and torque by about 15-percent and make an engine run crisper with better throttle response. Stage 1 mods also can help reduce engine heat, and there’s a good chance that fuel economy will get a boost, too. All good things.
Now, here’s how to get the maximum bang for the buck. Rather than opting for a full-system exhaust swap, you can start by choosing a good set of slip-on mufflers. The OE Harley head pipes work fine, flow fine and you can leave the necessary O2 sensors in place. It’s the mufflers that serve as the bottleneck in the exhaust flow, and there are plenty of good, reasonably priced alternatives. Speed’s Performance has applied Stage 1 mods to plenty of late-model Harleys and in the process tried and tested many different free-flowing slip-ons. And among their favorites is the new BUB 7. “These exhausts,” says ace tuner Wayne Hanson, “were designed from the get-go to enhance low-end torque. That’s perfect for a street bike where you want that low-end grunt, and these mufflers have it.” The BUB 7 has become really popular around the SPP shops. Along with torque boost the 7 offers a great tone, largely due to an end cap featuring a specially shaped internal taper that handles sound waves in a completely new way. It cuts the annoying high-frequency sound while maintaining a nice, deep rumble. These slip-ons also include a neat mounting system, an adjustable bracket for custom positioning, and the overall quality is top-notch. Each BUB 7 is even robotically polished.

Of course, if the budget allows there are full BUB 7 systems, too. The line includes a True Dual made specifically for baggers and there are 2-into-1 and 2-into-2 configurations, as well.
But back to the budget tune. Those free-flowing mufflers really need to be matched with an equally free-flowing air filter, and SPP’s own Speedy Flow kit is as good as it gets. And it’s priced right. The Speedy Flow uses a larger, deeper filter element that’s 5/8-inch wider than filters offered in other kits, and the filter element is washable and reusable. The assembly retains the OE cover or will accept most aftermarket covers, and its billet backing plate has a unique internal breathing system. With optional spacers it accepts Speed’s One-Way Crank Vents, too, another performance addition that doesn’t cost much. The new vents feature high-temperature Viton O-rings to eliminate pesky oil leaks and there are locking tabs to keep everything from working loose.
The final step—and it’s mandatory—is the re-map/re-jet session on the dyno. EFI bikes have a real leg up here, now that Dynojet’s Auto Tune has come into the picture. Using the new Power Commander V and Auto Tune a tuner can set a bike to perfection and it’ll stay that way wherever it goes, from sea level in Florida to a mile high in Denver. Talk about getting bang for the buck . . .
Take a look at the Speed’s Performance Plus web site for the full 2009 schedule, or drop by at one of their upcoming stops and talk to the guy. They’ll be at Ohio Bike Week, Sandusky, Ohio—June 5–14; Sturgis Rally and Races at the State Farm Insurance building—July 2–August 9; and at Austin’s Garage, Austin, Colorado, August 28–30. Ask about the budget Stage 1 tune that was featured in IronWorks.

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