Keeping your motorcycle’s bolts tightened to the correct torque settings is essential for maintaining safety, stability, and performance, especially if you ride a machine that generates significant vibration, such as a dirt bike, street bike, or dual-sport bike. In this guide, we’ll walk through a few tips and steps for checking and properly torquing bolts using a Husqvarna FC 350 as an example. While this is more specific to the Austrian bikes, the same principles can be used on all dirt bikes.
Why Torque Settings Matter
The bolts on your bike are constantly under stress from vibrations, which can cause them to loosen over time. Ensuring they’re tightened to the correct torque spec is essential, especially for parts like the swing arm pivot and engine mounts, which directly impact your bike’s handling and durability. A quality torque wrench, such as a 3/8″ drive wrench available from Dennis Kirk for around $77, is a worthwhile investment for any rider.
Tools You’ll Need
- High-quality torque wrench
- Zip ties
- Small bolts, if applicable
- Cutting tool for zip ties
Step 1: Remove the Frame Guard
To access the swing arm pivot nut on the Husqvarna FC 350, start by removing the frame guard. The guard protects your bike’s paint and provides boot grip but can hide the pivot nut. The frame guard is usually held in place by zip ties and a small bolt.
- Use a cutting tool to remove the zip ties holding the guard.
- Carefully unscrew any bolts holding the guard in place.
Step 2: Check the Swing Arm Pivot Nut
The swing arm pivot nut is one of the most vibration-sensitive bolts and is known to come loose frequently.
- Set your torque wrench to the recommended setting for the swing arm pivot nut, which for this bike is 100 Nm.
- Place the wrench on the pivot nut and apply torque. If the nut is loose, tighten it to the specified 100 Nm.
Step 3: Reattach the Frame Guard
Once the swing arm pivot nut is torqued, it’s time to put the frame guard back on.
- Start by screwing in the bolt by hand to avoid cross-threading.
- Secure the frame guard with new zip ties to keep it stable.
Step 4: Check Engine Mounts
Engine mounts are another critical area that can loosen, especially if the frame has been powder-coated or repainted, as the coating can compress over time.
- Set your torque wrench to the engine mount’s recommended setting, 25 Nm for this bike.
- Check each engine mount bolt on the frame and cylinder head. Tighten to 25 Nm if necessary.
Step 5: Check Motor Mounts
On the Husqvarna, the motor mounts are attached to a threaded sleeve on the opposite side of the frame. This design eliminates the need to hold both the bolt and nut while tightening.
- Adjust your torque wrench to the recommended torque for the motor mounts, which is 60 ft-lbs.
- Apply torque to each motor mount bolt, checking to ensure they’re all secure.
Tips for Success
- Always start bolts by hand to prevent cross-threading.
- Double-check each bolt even after torquing, as factory mechanics do.
- Consult your bike’s manual for specific torque settings, as these can vary by manufacturer and model.
- Keep a pack of zip ties handy—they’re incredibly useful for securing everything from frame guards to wiring.
Wrap-Up
Investing in a quality torque wrench and regularly checking your bike’s bolts are two of the best ways to keep your motorcycle safe and performing at its best. A $77 torque wrench is a small price to pay for peace of mind and extended bike longevity.
