Harley-Davidson ® FX/FXR Series (1979 - '94) Motorcycle Batteries

Reliability for the Purist: FX and FXR Battery Guide

The 1979-1994 period saw the transition from the iconic Shovelhead to the legendary Evolution engine. While the FXR was often outsold by its "prettier" Softail cousins during this era, it has become one of the most sought-after platforms for performance-minded riders today. Because these bikes are often kept as prized collectibles or built into "performance baggers," a high-quality battery like the Motocross Platinum YTX20H is essential to ensure they are always ready for the road.

The Platinum Advantage

The Motocross Platinum YTX20H is the definitive choice for riders who refuse to compromise on quality. Unlike budget-grade batteries that can struggle with the "kick-back" often associated with high-compression Big Twins, the Yuasa-made YTX20H features heavy-duty internal grids and superior plate density. This results in a battery that holds its charge longer during the off-season and provides a crisp, immediate start every time.

Frequently Asked Questions

Which models does this battery fit?

This category covers the FX and FXR series from 1979 through 1994. This includes the FX Super Glide, FXB Sturgis, FXWG Wide Glide, and the entire FXR family including the Low Rider (FXRS), Super Glide (FXR), and the legendary Sport (FXRT/FXRS-SP).

Is the YTX20H a significant upgrade over the original battery?

Many 1979-1994 models originally came with flooded (wet) batteries that required constant maintenance and were prone to leaking. The Motocross Platinum YTX20H is a modern AGM unit that is permanently sealed. Not only is it safer for your bike’s chrome and paint, but it also offers significantly higher cranking power and better resistance to the vibration inherent in older Harley frames.

Can I use a Lithium battery in my vintage FXR?

Yes, Lithium (LiFePO4) is an excellent option for riders looking to maximize performance by shaving nearly 10 lbs off the bike’s weight. However, because older charging systems and mechanical regulators can sometimes be inconsistent, we recommend ensuring your charging system is in peak condition before switching to lithium. Always use a Lithium-specific charger for maintenance.

How can I extend the life of my classic Harley battery?

Vintage Harleys are often stored for long periods between rides. To prevent the battery from sulfating and losing its capacity, we highly recommend a smart maintainer. A Battery Tender is the industry standard for keeping your Motocross Platinum battery at the perfect voltage during storage.

Model Fitment Reference

This category is the definitive source for batteries fitting 1979-1994 Harley-Davidson FX and FXR models, including:

• FXR / FXRS / FXRT: Super Glide, Low Rider, Sport Glide.
• FXWG: Wide Glide (1980-1986).
• FXEF / FXS / FXB: Fat Bob, Low Rider, Sturgis (Shovelhead era).
• FXLR: Low Rider Custom (Evolution era).