DR350 Clutch & Gearbox Fix

Many DR350 riders experience common, yet frustrating, issues such as difficulty finding neutral, a clutch that drags even when fully disengaged, or a gearbox that feels jammed. While some might dismiss these as quirks of the model, these problems can significantly impact your riding experience and, if left unaddressed, could lead to more serious issues. This guide delves into the common culprits behind these ailments and provides a comprehensive, step-by-step approach to resolving them by focusing on the clutch basket and associated components.

The Suzuki DR350 is often lauded for its versatility and reliability, earning it the nickname "Swiss army knife" of motorcycles. However, like all machines, it has its vulnerabilities. The most frequently reported problems revolve around the transmission and clutch system: difficulty finding neutral, a dragging clutch, and a jammed gearbox. Interestingly, these issues are often interconnected. A worn clutch component can easily lead to both a dragging clutch and the inability to reliably select neutral. A jammed gearbox can be a consequence of these primary clutch-related problems, or sometimes, a result of an improper fix for them.

A dragging clutch is most evident when your bike creeps forward in gear, even with the clutch lever fully pulled in, or when you feel a distinct lurch when shifting from neutral to first. This happens because the clutch isn't fully disengaging from the gears. This lack of disengagement directly contributes to the difficulty in finding neutral, as the gearbox components are still slightly engaged, preventing a clean shift into the neutral position. Even with precise footwork, selecting neutral becomes a game of chance. A common, easily overlooked cause of a dragging clutch is an improperly adjusted clutch cable – too loose, and the clutch will inevitably drag.

The jammed gearbox, where shifting beyond third gear becomes a struggle, might seem unrelated at first. However, its root cause often lies very close to the issues affecting neutral selection. It's often noted that these problems can be more pronounced when the engine is cold, though some riders report the opposite. Regardless, the common advice from some corners is to simply accept these as inherent characteristics of the bike. We, however, believe that the engineers at Suzuki intended for their machines to function optimally, and these issues point to something that can, and should, be rectified. Let's get started on fixing these common DR350 woes.

Before You Start: Essential Checks and Parts

Before diving into the clutch basket itself, it's crucial to address the simplest potential cause of your problems: the clutch cable. Ensure your clutch cable has the correct free play. If it's too loose, the clutch will drag, and you'll continue to struggle with neutral. A properly adjusted cable is fundamental. The jammed gearbox issue, however, is less dependent on cable adjustment.

If your clutch cable is correctly tensioned, it's time to prepare for the mechanical work. Here's a list of the parts you'll likely need:

Parts List

The part numbers listed are for a 1993 DR350, but they generally apply to other DR models, including those with electric starters.

Tools Required

Having the right tools on hand will make the process smoother:

• Torque wrench
• Thread locking fluid
• Engine silicone sealant
• Punches and hammer
• Screwdrivers
• Pliers
• Magnet (optional, for retrieving dropped parts)
• Brake cleaner
• Cotton buds
• Files
• Sandpaper (fine grit)
• Glass surface (for sanding)

Torque Specifications

Accurate torque is vital to prevent damage. Here's a quick reference:

Clutch Basket Disassembly: Getting to the Core

We'll assume you've already removed the clutch cover. If you need guidance on this initial step, refer to a dedicated clutch cover removal guide.

With the clutch cover off, the clutch basket is exposed. The first step is to remove the clutch plates. This involves undoing the six bolts that secure the clutch springs. Loosen these bolts gradually and diagonally to ensure even pressure release.

Once the bolts are removed, carefully take out the clutch springs. Then, you can remove the pressure plate that holds the clutch plates in place. Inspect the puller and its bearing for any signs of wear or damage. In our case, they appeared to be in good condition.

With the pressure plate removed, you can now carefully extract the clutch plates. It’s also a good opportunity to inspect the plates themselves. While less common, warped or damaged plates can contribute to clutch drag. Ensure they are flat and not exhibiting any signs of uneven wear.

Diagnosing the Neutral Gear Problem: The Missing Shift Drum Bolt

As you examine the clutch components, look closely for anything unusual. A common culprit for neutral selection issues on the DR350 is a missing or loose shift drum bolt. This small bolt plays a critical role in the gear-shifting mechanism. Without it, the gears can become loose and tilt, making it difficult to engage neutral. The shift drum bolt on the DR350 is known to sometimes come loose or even break.

In our scenario, the shift drum bolt hadn't broken but had vibrated loose and fallen into the oil sump. While a magnet might seem like the first tool to try, the bolt head can be too large. To retrieve it, we had to remove the oil sump driven gear. This involves carefully removing a securing ring and then the gear itself. Crucially, remember to secure the gear's pin, which can easily slide out, with tape to prevent it from getting lost. Once the gear is removed, the bolt can be easily retrieved. After retrieving the bolt, reinstall the oil sump driven gear and its securing ring.

Addressing Clutch Drag: The Clutch Bracket Spacer and Washers

Before reinstalling the shift drum bolt, let's tackle the components that can cause clutch drag: the clutch bracket spacer and its associated washers. The key here is to inspect the clutch bracket spacer washers.

Begin by carefully unlocking the original lock washer securing the inner clutch basket nut. Use a punch and hammer, applying gentle force to avoid damaging the surrounding components. Once the washer's fold is straightened, unscrew the nut holding the inner clutch basket. Remove the inner part of the basket, followed by the clutch basket itself.

Now you can clearly see the clutch bracket spacer and its washers. Damaged or grooved washers are a common cause of clutch drag. These grooves prevent the outer clutch basket from moving freely, leading to insufficient disengagement. If you find such grooves, these parts must be replaced.

While the clutch basket is out, it's worth inspecting the sides of its teeth for any dark bands or grooves. Some believe these can also contribute to clutch drag by allowing clutch plates to stick together. If you find them, carefully file them down to create a smoother surface. Ensure you thoroughly clean away any metal filings afterward using compressed air or brake cleaner.

An optional but potentially beneficial step is to increase the free play of the clutch basket on the spacer. This can be achieved by carefully grinding the spacer using fine-grit sandpaper on a flat glass surface. This addresses situations where the clutch basket might have been manufactured with too little end play, a rare but possible factory defect.

Reinstalling the Shift Drum Bolt and Fixing a Jammed Gearbox

With the problematic spacers replaced and the clutch basket inspected, it's time to reinstall the shift drum bolt. This step is critical, especially if you're also experiencing a jammed gearbox.

First, and this is a vital step, release the tension on the detent arm's spring. This spring is located below the shift drum bolt socket. If you fail to do this, you risk bending the detent arm as you screw in the shift drum bolt, which will necessitate replacing the arm and can lead to the very gearbox jamming issue you're trying to solve.

If your DR350 suffers from a jammed gearbox, pay close attention to the detent arm. A bent detent arm is a primary cause of this problem. When bent, it can obstruct the gear-shifting mechanism, preventing smooth gear changes. You can try to straighten a bent detent arm, or for guaranteed results, replace it with a new one (refer to the parts list for the part number).

Once you have a straight detent arm, reinstall it. Before screwing in the shift drum bolt, thoroughly clean its socket with brake cleaner. Apply a thin layer of thread locking fluid to the threads of the new shift drum bolt. This ensures it stays securely in place. Gently screw the bolt into its socket, and then use your torque wrench to tighten it to the specified 12 Nm. Remember, the detent arm should be able to move freely during this process.

Finally, don't forget to re-engage the detent arm tensioning spring that you released earlier.

Replacing the Clutch Bracket Spacer and Washers

Now, let's finalize the installation of the new clutch bracket spacer and its washers.

Place one of the new spacer washers onto the clutch basket shaft. Then, insert the new clutch bracket spacer into the clutch basket bearing bush. Next, position the clutch basket back onto the shaft, followed by the second new spacer washer.

Reinstall the clutch inner hub basket. Fit the new lock washer and the nut that secures the clutch basket onto the shaft. Tighten this nut to 40 Nm. It’s crucial not to overtighten, as this can crush the new spacers and negate your efforts, leading to the clutch dragging again. Ensure the outer clutch basket can still rotate freely with a small amount of play.

Lock the nut in place by folding the lock washer with a punch or screwdriver and then using pliers to bend it evenly. This prevents the nut from loosening over time.

With the main clutch components secured, reinstall the clutch plates and the pressure disc. Remember to ensure the puller and its bearing are correctly in place before fitting the pressure disc.

The final step is to refit the clutch springs and their retaining bolts. Tighten each clutch spring bolt to 4.5 Nm, again working diagonally to ensure even pressure.

Final Touches and Reassembly

With the clutch basket, shift drum bolt, and detent arm addressed, your DR350 should now shift smoothly and the clutch should disengage properly. The remaining steps involve reassembling the clutch cover with a new gasket and ensuring all external components are correctly refitted. If you're unsure about the clutch cover reassembly, consult a specific guide or video for your DR350 model.

By systematically addressing the common failure points, particularly the shift drum bolt and the clutch bracket spacer washers, you can effectively eliminate the frustrating issues of neutral selection problems, clutch drag, and jammed gearboxes, restoring your DR350 to its optimal riding condition.