How to Install a Weld-On Hardtail for a Sportster

Install a hardtail when building a custom Sportster with a low seat.

Converting a stock Sportster to a chopper includes removing the factory rear shocks and swingarm forks and welding a hardtail to the rear of the frame. The project involves stripping the motorcycle down to the bare frame and setting up the hardtail for attachment. Tube steel hardtails for Sportsters are available through custom shops and motorcycle accessory outlets. Installation requires mechanical expertise, metalworking tools and TIG or arc welding equipment.

Things You'll Need

• Safety glasses
• Work gloves
• Electric grinder with metal cutting disc
• Wire wheel
• 7/8-inch steel tubing
• Miter saw with metal cutting blade
• Welding gear
• Welding equipment
• Grinding wheel
• Spray epoxy primer

Instructions

1. Put on safety glasses and work gloves. Cut and remove the outer sections of the square seat mount at the rear of the frame with a grinder and metal cutting disc. This is necessary to fit the upper end of the hardtail to the upper frame tube of the motorcycle.

2. Remove the factory paint and primer from the rear section of the upper frame tube with an electric grinder and wire wheel. Remove the factory paint and primer from the swingarm attachment posts at the lower end of the Sportster frame with the grinder and wire wheel.

3. Place the Sportster frame on a work table. Position the hardtail at the rear of the frame and align the lower bars with the swingarm posts.

4. Measure the distance from the ends of the upper tubes of the hardtail to the sides of the upper frame tube of the motorcycle. With a miter saw and metal cutting blade, cut two pieces of 7/8-inch steel tubing to length as filler/extensions.

5. Weld one end of each filler/extension piece to one end of the upper tubes on the hardtail.

6. Position the hardtail at the rear of the frame and align the lower bars with the swingarm posts. Put on your welding gear. Tack-weld the lower bars to the posts with one tack weld at each bar.

7. Lift or lower the hardtail, as necessary so the ends of the filler/extensions align with the center of the upper tube on the motorcycle frame. Tack-weld the end of each filler to the corresponding sides of the frame tube.

8. Check the alignment of the hardtail before welding the attachments. Measure from similar points on each side of the Sportster frame to similar points on the hardtail. If necessary, cut the tack welds and reposition the hardtail so it's correctly aligned. Tack-weld the hardtail in place.

9. Weld the lower bars of the hardtail to the swingarm posts. Weld the ends of the fillers to the sides of the upper frame tube. Allow the welds to cool.

10. Grind the weld for a uniform appearance with the grinder and a grinding wheel. Apply two coats of spray epoxy primer to all welds and any bare sections of the frame. Allow the primer to dry before painting the frame and hardtail.

Tips & Warnings

• Always specify the model of the Sportster, such as XL883, XL1000 or XLCH 1200, when ordering a hardtail. Some bike shops will purchase the stock rear end components as spare parts for Sportster owners.

References

• Motorcycle Specifications: 1973 Harley Davidson XLCH 1000 Sportster
• Ironhead Bobbers: 1977 Harley Custom Hardtail Ironhead