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How to Replace the Clutch Basket in your Dirt Bike


Rob@ProX

Is your clutch having problems engaging and disengaging? Do you feel inconsistency through the clutch lever when operating the clutch? A worn clutch basket could be the cause. In this article, we’ll look at diagnosing a worn clutch basket, review replacement options, and step through the process of replacing the clutch basket so that the next time you need to tackle the job, you’re well prepared.

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Time to replace your clutch basket? Read on for a step-by-step on getting your clutch working smoothly again!

Diagnosing the Issue

Any clutch issues that a machine may have are typically very apparent to the rider because there is a complementary feeling of loss of control of the machine. The machine won’t become outright unrideable; however, subtleties that quickly become annoying will arise when utilizing the clutch. Most notably, modulation of the clutch may become more difficult, and the clutch feel will be inconsistent.

Before taking the machine apart, verifying possible simple issues such as clutch cable adjustment and that the engine or gearbox oil has been maintained regularly should be confirmed. To inspect and disassemble the clutch, the procedures outlined in the machine’s factory service manual should be followed. Once the clutch has been removed from the engine, inspecting its condition is straightforward.

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Double check that any issues you may be experiencing are in fact caused by a worn basket and not from a different culprit, like a clutch cable.

Click here for tips on replacing a clutch cable.

The basket consists of a series of “fingers,” or “tangs” which mate with the friction discs. The basket fingers drive the friction discs. The friction discs slide out when the clutch is engaged and back in when the clutch is disengaged. Due to this interaction, notching can occur on the edges of the basket fingers. Any notching that can be felt with a pick or a fingernail can be potentially problematic. In terms of clutch basket wear, the main grounds for replacement of the basket are worn and grooved basket fingers.

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Notching on basket tangs is typically part of normal wear and is the main reason to warrant basket replacement.

Replacement Options

The clutch basket is a great component to upgrade since it has surfaces such as the basket fingers that are inherently wear surfaces. Selecting a ProX basket, which is significantly stronger and more wear resistant than OE baskets, has a high return on investment in terms of reduced maintenance and improved performance. ProX clutch baskets are precision machined from forged 7075-T6 aluminum, which is one of the strongest alloys on the market. Wear resistance is ensured by utilizing a sophisticated hard anodizing process. A final layer of performance is added in the form of a Teflon coating which seals the basket surfaces and allows the friction discs to slide effortlessly over the clutch basket fingers while in operation.

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ProX clutch baskets are forged from aluminum, precision machined, and hard anodized and Teflon coated for smooth clutch actuation. The tensile strength of the material combined with the coatings make notching the basket tangs almost impossible.

Find ProX clutch components for your bike or ATV here!

Tools Required

The clutch basket is an assembly of parts including the basket, starter gear, clutch driven gear, dampers, and backing plate. The starter gear is pressed into the clutch basket, and the driven gear, dampers, and backing plate are riveted or screwed in place. When it comes to tools, you’ll need the following, outside of your standard tools used to remove the clutch from the machine:

  •  Hydraulic press or vice - capable of exerting up to 8 tons of force.
  •  Center punch, drill and drill bits, or grinder, or mill - for removing the rivets
  •  Punch and hammer - for driving the rivets out of the assembly
  •  Torque wrench and Loctite - for securing the screws in the new basket
  •  Fixturing - for adequately supporting the basket while removing and installing the starter gear. The fixturing doesn’t have to be anything fancy, and examples are provided later in this article.

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There a number of tools required to do the job correctly. For example, having the ability to properly press the starter gear out and in is key to retaining proper function.

The Process

We’re going to jump into the process post clutch removal and focus on servicing the basket. ProX clutch baskets include new dampers and screws along with instructions for your specific application. The following instructions should be considered supplementary.

  1. Mark the backing plate and gear - Use a marker to mark the outside surfaces of the backing plate and gear. Doing so will ensure that these parts are installed in the correct direction when reassembled.

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  2. Removing the rivets - It is preferable to drill the rivet heads off, however, grinding and milling the heads off are also acceptable options. When drilling, it is best to start by using a center punch to indent the center of the rivet so that the drill bit will not walk. Once center punched, start with a small drill bit and work up to a bit that is slightly smaller in diameter than the rivet itself. Only drill down far enough to remove the head from the rivet. Typically, a depth of 0.040 - 0.080” (1-2mm) below the surface is all that is required to drill out the rivet head. After the rivet head has been drilled out, use a punch and hammer to drive the rivet out of the assembly. 

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    The most recommended method to remove the rivets is to drill the heads off then use a punch to remove the rest of the rivet completely.
     
  3. Remove the driven gear - Pull the backplate off before removing the driven gear. Note the orientation of the dampers. Take the driven gear off, then remove the dampers.

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    Make sure you note the orientation of the dampers before removing them all after removing the driven gear.
     
  4. Remove the starter gear - The starter gear utilizes an interference fit with the clutch basket, so it will have to be pressed out. The exact geometry of the starter gear will be model specific. Some starter gears will feature teeth that bite into the clutch basket. Depending on the starter gear geometry and geometry of the clutch basket, it is possible the clutch basket will be destroyed during the removal process. 

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    Starter gears will differ depending on the model. Make sure it's adequately supported to press out without damaging the gear.

    Adequately support the clutch basket around its base so that loads applied will transfer through the center of the basket. Standoffs may need to be utilized to support the basket properly. Select an appropriately sized spacer to place between the starter gear and press. Appropriately sized sockets can serve as suitable spacers. Carefully press the gear out of the hub.

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    There's a good chance the old basket may break when pressing the starter gear out. This is fine, the focus is on not damaging the gear itself.
     
  5. Clean the parts - Remove any clinging material from the starter gear, clean the driven gear and backplate.
     
  6. Install the starter gear - Apply engine oil to the outside of the starter gear. Carefully position it in the center of the new clutch basket. Before pressing it in, be sure to confirm any specific press-in depth requirements outlined in the instructions. Ensure the clutch basket is adequately supported before pressing the gear in place. The press force required to install the gear will be model specific and highlighted in the installation instructions.

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    Be sure to oil the starter gear and note any depth and force specifications for your specific application.

    On some models, a simple shrink fit is utilized to install the starter gear. When this process is specified, follow the heating instructions for the clutch basket. Once up to temperature, carefully drop in the starter gear.
     
  7. Install the driven gear and dampers - Place the driven gear on the clutch basket noting any orientation requirements previously identified. Install the new dampers in the correct orientation.

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    Install your new dampers in the correct orientation and reinstall the primary gear.
     
  8. Install the backplate - Double check the orientation of the dampers and driven gear. Install the backplate onto the clutch basket, noting any orientation requirements. 
     
  9. Torque the backplate screws - Consult the installation instructions for the proper torque specs, apply Loctite if the screws are not pre-Loctite, then tighten in a cross-pattern.

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    Reinstall your back plate with new screws and thread locking compound and torque them to spec.

At this point, the clutch basket is ready for service and can be reinstalled on the engine. Refer to your service manual for assembly instructions and specifications to reinstall your clutch and button up the engine.

The process of replacing a clutch basket is straightforward and can be executed by anyone so long as the necessary steps are followed and tools are available. We hope this write-up simplifies the job and helps our fellow riders and racers get back out there performing better than before!

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  • Similar Content

    • By Kevin from Wiseco
      The clutch system is the most important connection between your hand and the rear wheel, as far as controlling the machine. When working properly, most riders don’t give their clutch a second thought. However, the importance of the clutch quickly snaps into focus when there’s a problem with the system.
      A clutch is an engineering marvel. Imagine you are on the starting line waiting for the gate to drop. You start your bike and pull in the clutch. What follows is a chain reaction of events. A series of moving parts transfer that load down to the clutch, where the pressure plate is pushed away from the clutch pack, basket and inner hub. At that point, there is a disconnection between the transmission and crankshaft.

      Clutch functionality involves a series of moving parts that are crucial to engine operation. Periodic maintenance, inspection, and replacement will keep your machine running as it should. Shown here is an exploded view from Yamaha of a YZ250 clutch.
      With the clutch disengaged, you click the shifter into gear. The gate drops, and you quickly release the clutch lever. The clutch springs force the pressure plate to squeeze the friction and drive plates together, causing the clutch basket and inner hub to synchronize. At that point, the energy generated inside the combustion chamber is carried through the transmission and to the countershaft sprocket, which then transfers the load to the rear wheel. Without an operating clutch, you would be sitting on the starting line as the pack raced away.  
      Suffice it to say that your clutch is a vital piece of the overall puzzle. And, like most parts on your bike, it won’t last forever. Fortunately, there are three general indicators that your clutch is not working properly. You don’t need to be deft or dexterous to determine whether your drive system is giving up the ghost. The only necessities are a handful of tools, basic mechanical knowledge, and a good sense of smell. In this article, we delve into the symptoms, causes and solutions for the most common clutch problems so you can get back to riding.

      Sign #1: Slipping Away
      Symptoms:
      A slipping clutch is quickly recognizable when you’re twisting the throttle with reckless abandon while the machine is in gear, yet the rear wheel isn’t rotating in unison with the engine’s rpm. If you’re wound out in third gear and only accelerating at a snail’s pace, then something is wrong. You may also be able to notice a vague feel at the clutch lever. Either of these symptoms suggest that the internal clutch components need to be inspected for wear.
      Causes:
      When a clutch is performing optimally, the drive plates and friction plates are pushed together during clutch engagement (i.e. when the clutch lever is let out). The connection causes the rotation of the clutch basket and the inner hub to synchronize and work as one unit. However, as the plates begin to wear out, the clutch plates will slip against each other instead of grabbing. This prevents the transfer of energy from the engine to the transmission. Unfortunately, clutch slipping is inevitable, even if you aren’t a clutch abuser. Clutch plates wear out over time as a result of rubbing when the clutch is engaged.

      When experiencing clutch slipping, the likely culprit is worn clutch plates. It's time to disassemble and inspect your steel and fiber plates for wear.
      It is also possible that the clutch springs have lost their tension. When this happens, the springs aren’t strong enough to effectively pull the pressure plate against the clutch pack. Just as with clutch plates, clutch springs do not last forever.

      Worn clutch springs can also contribute to a slipping clutch. Read on for an explanation on inspecting your clutch springs.
      Solutions:
      When you experience clutch slippage, you’ll need to inspect the drive and steel clutch plates, as well as the clutch springs. To quote Dave Sulecki, Wiseco Powersports Engineer, “It’s very easy to access the clutch on all the new bikes. You can literally lay the bike over on its side, pop off the clutch cover, and start inspecting the components.”
      Using a vernier caliper or micrometer, measure the thickness of the steel (or aluminum) drive plates, and the fiber plates. Consult your owner’s manual to find the recommended specs. Be sure to also check the free length of the clutch springs. It’s a good idea to replace the drive and fiber plates, as well as the clutch springs.
       
      The most accurate way to know if your steels and fibers are worn is to measure them and compare the thickness to the recommended spec range in your owner's manual.

      Similarly, clutch spring free length can be measured to determine if they are outside of spec and need to be replaced.
      Replacement clutch components—both in individual components and clutch pack kits—are readily available through aftermarket companies like Wiseco. Replacing your fiber and drive plates at the same time is common practice, and when springs are required as well, all these components are available in kits with fibers, plates, and springs in one box. Each kit is built to OEM specifications and far less expensive, and Wiseco clutch springs feature a stiffer rating for a more positive clutch engagement.

      Replacement clutch components from Wiseco are available in individual packs of steels, fibers, and springs, as well as in clutch pack kits that include all three.
      Find Wiseco clutch components for your bike or ATV here.
      Sign #2: Creeping & Bad Smell
      Symptoms:
      The machine is emitting a foul burning smell that could strip paint off a wall. The stench might be so pungent that it’s evident after pulling into the pits. Generally, though, the smell is noticeable after removing the clutch cover. You may also notice your bike creeping forward with the clutch pulled in and the transmission in gear, no matter how much you adjust the clutch cable.
      Causes:
      Do the sniff test. Pull the clutch cover off. If you smell burnt clutch material, chances are your clutch will need new components. The burnt smell is the result of the clutch heating up.

      “The parts that burn first are generally the friction plates. It’s a real obvious odor. You’ll know it when you smell it. Visually, you’ll see the heat marks in the drive plates. The friction plates can also become black in color. The best thing to do is check the plates dimensionally against the specifications in your owner’s manual. Make sure you’re within tolerance on width and flatness,” states Sulecki.
       
      Burnt friction plates will typically become black in color and burnt drive plates commonly show dark colored wear marks.
      Solutions:
      For starters, you’re going to need to replace the oil. Be sure to pay close attention to the recommended service intervals in your owner’s manual. Doing so can extend the life of your clutch.
      Sulecki adds, “Fresh oil will help keep things lubricated and running cool. Oil does break down from heat and friction over time. In a lot of engines, the clutch shares oil with the transmission and valve train. Oil gets a lot of opportunity to break down quickly. Keep the oil fresh.”
      However, the damage of a cooked clutch cannot be undone. Clutch plates can warp over time from the heat. Warped plates cause the clutch to disengage unevenly and create all sorts of headaches. You will need to invest in new friction and drive plates, at least. However, heat could also damage the clutch springs, effecting spring tension. Be sure to inspect all your clutch components.

      If you find your clutch components have been subjected to excessive heat, it's always a good idea to at least replace the drive plates, fibers, and springs (when applicable).
      Sign #3: Feeling A Drag
      Symptoms:
      The clutch lever feels lumpy during clutch engagement/disengagement. Sometimes the lever can feel jerky. These are telltale signs that the clutch basket and/or inner hub is damaged and needs inspection.

      Causes:
      If your machine has the OEM/stock clutch basket, it was likely made using a diecast aluminum material. While fairly lightweight, durability is not stellar.
      “When you cast aluminum, you take molten aluminum and pour it into a mold. Once it has solidified, it gets processed from there into a finished part. When the material is molded it is generally not very dense. You get a lot of voids, porosity, inclusions, and imperfections in the material. The constituents inside the material aren’t bonded tightly against each other,” states Sulecki.
       
      The most common wear on cast clutch baskets is notching on the edge of the tangs where the clutch plates engage. The inner hub can be inspected for similar wear. If you see notching like this, it's time for a replacement.
      Solutions:
      There are a variety of aftermarket clutch basket options that use different manufacturing processes. Billet is a common alternative to casting, but even that has downfalls.
      Sulecki explains, “With billet, you’ll start with a cast piece of aluminum. It will generally get compressed a little bit in a forge press or some sort of pressure casting. That’s to condense the material a little tighter. Then the part is machined from the solid piece of metal. It has slightly better properties than a cast part, but not as much as a forged part.”
      Forging is a very intricate and involved process. It begins with a cast and drawn bar of aluminum material, which is then smashed until all of the molecules are bonded to each other. This makes the material much denser and creates what engineers refer to as feature aligned grain flow. Basically all of the grains in the material are forced to flow up through the features–particularly the tangs on the clutch basket and stanchions on the inner hub–for greater strength. All of the material properties improve–from tensile to fatigue to ultimate strength. Ductility is also improved, meaning the material can bend before it breaks.

      Cast and billet constructed clutch baskets are susceptible to wear. This is why Wiseco forges their clutch baskets in house before machining them, achieving greater tensile strength and wear resistance.
      Sulecki adds, “The denser material is very resistant to impact and fatigue, which are two critical components of a clutch basket. Impact is caused by the clutch plates as they drive against the tangs on the clutch basket. Clutch plates will actually start to create indentations on a stock cast part, and dimples on a billet basket. In turn, the plates can’t slide smoothly across the width of the tab as you pull in the clutch lever to disengage the clutch. A forged clutch basket’s resistance to impact means that it will not develop notches in the tangs.” Suffice it to say that forging is the superior material for clutch basket durability and lasting performance. 
      Check out all the technical details on Wiseco clutch baskets here.

      The forged material creates much greater resistance to impact from the clutch plates during operation, providing a seemingly lifetime solution to tang notching.
      To cap it off, Wiseco hard coat anodizes and coats their forged clutch baskets with Teflon. Hard coat anodizing aids in wear and abrasion resistance, as well as improves lubricity and corrosion resistance. Teflon coating is the last process. It helps fulfill the wear resistance and lubricity that Wiseco requires for their clutch baskets.

      Hard coat anodizing and teflon coating finish off Wiseco clutch baskets for ultimate wear resistance and smooth operation.
      Find a Wiseco clutch basket for your machine here.
      Lifetime Guarantee
      It’s interesting to note that Wiseco has been manufacturing forged clutch baskets, pressure plates and inner hubs for years, but this all-too-important detail has flown under the radar. “Our forged clutch basket is the best product we make that nobody knows about,” says Sulecki. The performance-driven powersports magnate is so resolute in the durability of their forged clutch baskets that they offer a lifetime guarantee against notching and breakage. What does that mean? You’ll buy it once and never have to worry about it again.

    • By Dylan Swicegood
      Recently got this bike and it was pretty neglected by previous owners. I decided to do some maintenance due to the fact that I broke my wrist.
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    • By Ian Oakes
      Hi,
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      I have never paid for a brand new dirt bike but might consider it sometime in the future. What's your guys' opinion on maintenance on a newer bike. Is it hard or easy? I have no problem working on dirt bikes at all but have never worked on things like fuel injection, air forks, etc.
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