Clutch baskets take a lot of abuse. The tabs on the clutch friction plates rub against the tangs on the clutch basket, after a while the tangs on the basket become badly notched. The notches keep the plates from sliding up and down properly when engaging/disengaging the clutch. As a result, the clutch becomes grabby (or less smooth), shifting or finding neutral might become difficult, and the bike might even want to creep with the lever pulled in. The solution to these symptoms of a notched clutch basket is to replace it.
The rate at which a basket wears depends mostly on the rider’s style (assuming your cable is adjusted properly). Do you feather the clutch a lot to stay on the pipe? Do you ride in a lot of mud or deep sand? Do you slip the clutch excessively to sling shot out of the corners? Some riding styles are just harder on clutches than others. Pro’s can waste a basket in one race. Weekend warriors can ride for years and never wear out their basket. Regardless of how long it took to wear it out, there are a couple of options for replacing it.
You can buy a new OEM clutch basket complete with the new ring gear and kickstarter gear, but OEM baskets are made from inexpensive die cast aluminum. Even though they are usually made of a high-silicon alloy, the bare aluminum is prone to wear and notching. Aftermarket clutch baskets are generally much stronger than OEM baskets, sometimes lighter, usually have oil holes to help with oil flow through the clutch, and are hard-plated to resist wear from the clutch plates. Installing a new OEM basket is quick and easy because the gears come already installed. However if you want the benefits of smoother operation, better oil flow, and significantly better wear resistance, you will need to perform the following steps to make the switch to a good aftermarket basket.
1. Remove your old clutch basket from the bike as described in your service manual. (You can also refer to the tech article “Basic Clutch Maintenance” for a more general description of the process.)
2. Your aftermarket clutch basket should come with installation instructions. The first step is to remove the ring gear from the OEM basket. This can be done by center punching the rivets and drilling them out. You could also grind them off, or better yet, mill them off if your uncle will let you into his machine shop. The important thing is to NOT DAMAGE the ring gear during the process, as it will be re-used with your new clutch basket.
3. Once the rivets are removed, pull the ring gear off the back of the basket. Pay CLOSE attention to which side of the gear was up, as it will need to go onto the new basket in the same orientation.
4. Remove the rubber cushions from the OEM basket. Pay close attention to which way they are oriented on the cushion bosses. Some baskets are designed so the cushions can only go on one way. Other models have symmetrical cushion bosses, so the cushions could go on either way. It is very important to the proper function of the cushions to install them in the same orientation in which you removed them.
5. If the kickstarter gear (small center gear) is separate from the ring gear, press it out of the center of the basket. If you don’t have access to a small press, applying a little heat around the center gear should expand the basket enough and make the kickstarter gear easier to remove. (Make sure you have removed the rubber cushions before putting any heat to the basket.)
6. Clean all components to remove the machining chips and clutch debris.
7. If the kickstarter gear is installed separately from the ring gear, install the kickstarter gear into the center of the new basket first. Most basket manufacturers will recommend putting the gear into the freezer for 15 minutes and the basket into the oven for 15 minutes. This makes the gear drop in very easily.
8. Install the cushions in the proper orientation. Check the installation instructions to make sure the cushions are oriented properly.
9. Install the ring gear over the cushions. Generally if there is a bevel on the ID of the gear, the bevel will go down. If there is no bevel or a bevel on both sides, generally the recessed side of the gear will go up. Check the installation instructions to make sure the gear is installed with the right side up. If there is a large height difference (more than 1/16”) between the ring gear where it goes around the cushions, and the top of the cushions, you could have the gear on upside down.
10. Install the gear retainer plate. Most aftermarket baskets come with a new retainer plate. If yours did not, hopefully you didn’t annihilate your OEM plate when you were drilling or grinding off the rivets, as you will need to reuse it.
11. Install the new fasteners. I am a fan of the Wiseco baskets because most models come with a hex bit socket for installing the fasteners, and the new fasteners come with pre-applied thread locker already on them. Hinson baskets come with new screws as well. If the screws do not have thread locker already on them, apply RED loctite to the clean dry screws prior to installation.
12. Torque the new fasteners according to the torque specs from the basket manufacturer.
13. Lastly, flip the basket over and peen the ends of the fasteners where they come through the bottom-inside of the basket. What I mean by peen is take a center punch and smack the end of the screw to deform the threads on the end. This will ensure the screws cannot back out during use.
14. Go back and re-read steps 12 and 13. They are VERY IMPORTANT!
15. Install the clutch basket back into the bike as described in your service manual.
It is always best to service the entire clutch pack at this time by inspecting/replacing any other clutch components that are worn or out of specification. Finally, adjust your cable properly before hitting the trail/track.