1. Most people don't think about their bike's clutch. Sure riders use it every time they ride-they may even do the right thing by adjusting and lubricating the cable occasionally. But really think about the clutch? Never; that is until it starts to get cranky and becomes grabby or just gets lazy and starts to slip. (Been drag racing, have you?) Although you can often get away with only replacing the clutch's fiber plates, we usually replace all the plates and springs to assure that everything is within specs. For this installation, Barnett supplied us with new Kevlar(r) friction plates, steel plates, and springs. After gathering all the parts, any mechanic-even a novice-can replace a clutch in about an hour. Of course you also need a shop manual and a clean place to work. Music is always nice, too.
2. Start by leaning the bike away from the clutch side so that the oil will stay put when you get the clutch cover off. (If you're replacing the clutch after it failed, you should change the oil and filter since they're most likely contaminated with clutch-plate particles.) Next, loosen all of the clutch cover bolts in a crisscross pattern. Pick a point on the cover (mark it with a grease pencil if you're forgetful), remove the bolts one at a time in either a clockwise or counter-clockwise direction, and place them in order on a clean shop rag. Locate the pry tabs on the clutch cover and gently pry the cover free of the case with a screwdriver or pry bar. (Although some people say you can save the gasket if you remove the cover carefully, we recommend buying a new one to assure an oil-tight reassembly.)
3. Next remove the five or six clutch pressure plate bolts with a ratchet or air wrench. Take note of any alignment marks on the clutch pressure plate and inner hub that may need to be matched on reassembly. Remove the pressure plate and set it aside. The throw-out bearing in the center of the basket may fall out as the pressure plate is removed. If it does, check for alignment marks and place it back in position.
4. Using the tips of your fingers or a pair of curved picks, remove the clutch plates one at a time and stack them in exactly the same order. Note the plate order for installation. Incorrectly stacked plates can cause premature clutch failure.
5. The importance of how carefully parts are set aside can't be understated. This practice not only helps eliminate the loss of important parts, but also makes it possible to go back to the job without confusion if an interruption forces you to stop for awhile. Here the clutch plates are zip-tied together to maintain their order prior to inspection. If fasteners are arranged neatly and logically, reassembly of the clutch pack and covers will be much easier for novices and experts alike. Trying to figure out which bolts belong in which hole is time consuming and terribly dull. ("Nope, doesn't fit there. Not here either. Dang. Only 12 more to go....")
6. While the clutch is apart, inspect the clutch basket's inner and outer hubs for wear. If any notches or grooves are visible, the basket may need to be replaced. Consult your shop manual or local mechanic for information on how to remove the basket's hubs. Unfortunately, some engines require that the cases be split in order to replace the hub/basket assembly. Remember, installing a new clutch into a worn basket may result in abrupt clutch engagement or clutch chatter.
7. If you don't plan on replacing the steel plates at the same time as the fiber ones, check them for any signs of wear, such as discoloration or scoring. Measure the steel plates' thickness to make sure they are within suggested tolerances. Make sure the plates are not warped by placing them on plate glass or another flat surface. If any of the plates do not lay flush to the surface or can be rocked in any direction, replace the plates as a set. Because we hate doing the same job twice, we chose to replace the steel plates even though the stockers showed almost no signs of wear.
8. Before assembling the new clutch pack, soak the fiber plates in fresh oil for about five to ten minutes. When sliding the plates into the clutch basket, be sure to arrange fiber and steel plates in exactly the same order as the old clutch pack. If you are unsure, the innermost and outermost plates are usually fiber-but check your shop manual before proceeding. The steel plates are usually made of stamped metal, with one rounded edge and one sharp edge. Some mechanics say the steel plates should be installed with the sharp edge facing the pressure plate to avoid excessive outer hub wear. Barnett says that all the steel plates must be installed the same way and that it does not matter if the sharp edges face in or out.
9. Place the pressure plate over the clutch pack. Remember to match up any alignment marks on the clutch plate and inner hub. Install the springs into the pressure plate and screw the bolts in until snug. Be sure to install the springs and bolts in a crisscross pattern for even pressure on the plate. Using a torque wrench, tighten the bolts-again in a crisscross pattern-to the shop manual's specified torque. While some people may proclaim with pride that they never use a torque wrench, we've found that properly torqued assemblies (clutch and otherwise) fail much less frequently. Again, although the OE springs showed no signs of wear and exceeded the minimum length specifications, we chose to replace them with Barnett springs. While the Barnett springs are stiffer and require a slightly firmer pull at the lever, the company says that the additional tension provided by the springs helps make engagement of the Kevlar(r) plates more progressive.
10. Clean off any remnants of the old gasket with a knife or gasket scraper. (Sears manufactures a nifty gasket scraper that features interchangeable stainless steel blades to ease scraping a variety of shapes.) Be careful not to score the sealing surface. Chemical strippers, like naval jelly, can help in particularly tough cases, but be careful to keep these chemicals away from all painted parts. Make sure all gasket pieces are removed. Clean the mounting surfaces with a solvent such as contact cleaner to make sure no oily residue remains to interfere with gasket adhesion. When using toxic chemicals such as contact cleaner, be sure to wear latex gloves to preserve the sanctity of your precious bodily fluids.
11. Apply a thin coat of gasket sealant to both gasket mounting surfaces. If you are unsure of where to apply the sealant, look at the shape of the gasket. We've found that the pliable, non-hardening sealant works best on covers such as the clutch cover. After allowing the sealant to skin over for several minutes, place the new gasket (remember the $12 you save by reusing the old gasket will seem inconsequential if the cover leaks oil) in position on the engine case. The sealant should hold the gasket in position. Make sure the dowel pins in the case (if any) are in place before mounting the cover. Reinstall the clutch cover bolts in the same order that they were removed, but do not tighten more than finger tight. Once all the bolts are installed, torque them to the factory specified setting in a crisscross pattern. Let the bike sit for an hour or so to allow the gasket sealant to set before taking your bike out for a ride. Your new clutch will most likely engage in a slightly different lever position, but you'll also notice how much more positively it engages when compared to the cranky old clutch you removed.
HANDS ON TOOLS
Replacing the clutch on almost any bike usually requires only basic mechanic's tools: A good set of sockets, allen sockets, a couple of extenders, a ratchet, a torque wrench (measuring in inch pounds), a big flat head screwdriver (a technical term) or small pry bar; a pan for soaking the plates in oil, a gasket scraper, and some gasket sealer. Of course you'll need a shop manual and a clean place to work also. Perhaps even a cold one....