How To Replace An OEM Clutch Basket
The OEM clutch basket and drive cushions on most dirt bikes, (especially those of the larger displacement) are prone to wear and grooving of the outer fingers of the basket (as well as on the inner hub) which often leads to, or results in broken clutch plates, a clutch that drags, (a bike that tries to creep when in gear and the clutch is pulled in.) or just an overall crappy feeling clutch, both at the lever, and with the way it engages or disengages.
Lucky for us, the aftermarket industry has responded to the inadequacy of the OEM baskets with high quality replacement clutch baskets which are generally carved from a chunk of aluminium to earn the classification of "billet", then they are hard anodized for additional wear resistance and are of a much higher quality than that of the OEM clutch basket.
Replacing a clutch basket does require grinding or drilling on the original unit but it isn't difficult, and it's something that a home mechanic should have no problems with completing if equipped with a decent arsenal of tools that include a torque wrench, a small press (Available at local tool outlets or auto parts stores), a torch (preferably Oxygen / Acetelene), hot plate or oven and a hand held grinder.
How to Replace A Clutch Basket on a Dirt Bike
Before embarking on replacement of the OEM basket, it's recommended that you have a factory service manual specific to the motorcycle on hand, as these are critical for details and specifications specific to the motorcycle being serviced, including exploded diagrams of assemblies, as well as you'll be needing this for torque specifications and future reference. Additionally, ensuring the area around the clutch cover is clean is always a good idea and washing the dirt bike before getting started never hurts.
- Before getting started, if the motorcycle is liquid cooled you'll want to drain the coolant from the cooling system.
- Next, turn the gas off if it's a carbureted bike, then lay the bike over and place the end of the handlebars on a motorcycle stand as this will make removal and installation of the clutch cover and clutch components much simpler since they'll then be facing you, as well as you'll be avoiding any unwanted messes that accompany a constant drip of engine oil or coolant.
- Now remove the clutch cover, pressure plate, clutch lifter, inner hub and clutch plates as detailed in a factory service manual, or in our article covering clutch replacement, then be sure to inspect all these pieces as detailed in the previously mentioned article, ordering worn parts as necessary.
- Next, with the aforementioned parts removed, remove the clutch basket from the transmission input shaft, then hold the basket over an oil drain and hose it down with a solvent such as "Brake Clean", then blow it dry with compressed air to remove a majority of the residual oil and let's get started.
As you'll notice when comparing the original clutch basket to the replacement, it will be necessary to transfer the original primary gear and kick start gear, or center hub to the new basket, so let's get started:
- With the Clutch basket in hand, the first step is going to be to remove the primary gear from the original basket.
- Begin by placing the clutch basket on the bench so as to enable removal of the rivets from the back side, then in an area clear of the motorcycle, or any exposed internal parts either grind these rivets flush, or drill them out with a .250 inch drill bit.
Grind 'em, Don't Drill 'em
You'll find that drilling these rivets is not easy, but grinding them doesn't look easy either because you're scared of hitting the plate... Go ahead and grind and don't worry about the plate. A new retainer plate comes with a new clutch basket, just don't hit either of the gears with the grinder!!
Note: Pay close attention to the direction of the primary gear, as it's possible, (and easy) to reinstall the primary gear upside down.
- With the rivet's ground flush, (or drilled), use a flat blade screwdriver and remove the thin metal plate covering the primary gear, then the primary gear.
- Once the primary gear has been removed, remove the cushions from their bosses and discard these.
- Now with everything removed from the clutch basket with the exception of the center gear / hub, place the clutch basket in a press (Do NOT use a Hammer and Socket or Punch)then press the center gear out of the basket with a large diameter socket while paying close attention to any shims or spacers remaining on the gear, or stuck to the clutch basket itself upon removal of the gear from the basket.
- With the center gear separate from the clutch basket, clean this and any accompanying spacers or shims, then coat the splines of the gear with a light coating of clean motor oil, then place the gear with any spacers, or shims in place into the freezer for a few hours (overnight is better) as this will effectively shrink the gear slightly, greatly simplifying installation to the new basket.
- After the gear has been in the freezer for a few hours (or overnight), if possible place the new clutch basket in an oven for 30 minutes or so at about 200 degrees Fahrenheit.
If an oven is unavailable for this, carefully and uniformly heat the area where the gear is to be installed using a circular motion with the torch, being careful to not focus too much heat on any one area, but to uniformly and evenly heat the center of the new clutch basket to approximately 200 degrees Fahrenheit.
- With the gear having been in the freezer for a length of time, and the new basket heated up, grab the gear from the freezer and quickly install it with any accompanying spacers or shims to the new clutch basket.
- Using care to ensure everything remains straight, with the gear cold, and the basket warm, place the gear with any thrust washers attached into the clutch basket's center hub.
If done properly, the gear should sit flush in the basket without requiring press work although if press work IS required, be sure to support the underside of the clutch basket and Use a press and do NOT hammer the gear in.
- With the kickstart gear seated in the new clutch basket, you can now install new cushions, then the primary gear while paying close attention to the way it was removed, then install the retaining plate taking note of the direction of the chamfering for the screw head relief.
- Using the screws which were supplied with the new clutch basket, ensure they already have a locking agent on the threads, or after applying a coating of red loctite to the threads, torque these screws per the accompanying instructions then reinstall the clutch basket to the motorcycle torquing things as indicated in an OEM service manual specific to the bike.
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