exhaust diameter

Aftermarket Pipes Backfire

Our Friends at SuperTrapp had this to say: Do aftermarket pipes backfire? A backfire or “lean misfire” on deceleration is primarily attributed to an improperly tuned engine. Under this circumstance, the low speed fuel circuit needs to be adjusted. On a street bike, the rule of thumb is to adjust the fuel mixture screw out

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Two Ways to Map an EFI?

I have been told that there are two ways to map an EFI. One being to actually change the mapping of the ECU by getting a flash download. The other way is to use a piggy-back modem type device that allegedly alters the signals that are being received by the actual ECU. Provided that this

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harley speed sensor, Harley Davidson speedometer and engine issue

Performance and Match Air Intake

Q: What are some guidelines for optimum performance when matching an aftermarket air intake with either a stock H-D or other aftermarket carb on the Twin Cam?   Our Friends over at Wimmer Custom Cycles  had this to Say: Most important is maintaining the correct air to fuel ratio. Keeping in mind more air more

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harley speed sensor, Harley Davidson speedometer and engine issue

Air Filter Service

After installing a “open” performance air cleaner “filter” how often should you change the filter since it’s open to more elements?   Our Friends over at Wimmer Custom Cycles  had this to Say: That of course depends on your riding area and style. Wimmer filters never require oiling, thus they can go much longer with

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harley speed sensor, Harley Davidson speedometer and engine issue

Best Air Intake for My Bike?

How do I select the best performance air intake for my bike?   Our Friends over at Wimmer Custom Cycles  had this to Say: All of our intakes will offer superior performance over stock. The look and style of the intake is more of a preference issue. However some intake systems offer more performance than

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