bike clutch – AdventureBikeTroop

The clutch on a motorcycle has an important, but tough job. It has to transfer all the power from the engine to the gearbox and back wheel. Due to the nature of the job, a clutch does not last forever. But how long can you expect your motorcycle clutch to last? The life of a motorcycle clutch varies greatly. Typically you can expect your a motorcycle clutch to last between 20 000 and 60 000 miles. A clutch that is often slipped in the friction zone and that is not properly maintained may need replacement after as little as 5 000 miles, while many riders do well over 100 000 miles on the original clutch. There is no average life for a motorcycle clutch. It totally depends on the life it leads. I've never had to replace a clutch on a motorcycle and I've heard of many riders doing well over 100 000 miles on the original clutch. Then there are those who wheelie and do drag starts at every opportunity. Clutches do not appreciate this sort of hooliganism and may decide to retire early. The Average Lifespan of a Motorcycle Clutch It is nearly impossible give an average mileage that a motorcycle clutch will last. The lifespan of a motorcycle clutch will depend on the type of clutch (wet or dry), the brand and how well it is maintained. The main factor affecting clutch life, however, is how it is used by the rider. I did some research by reading the top 15 forum threads I could find on the life of motorcycle clutches. Before we dive into the different types of clutches and how they work, let's have a look at the first-hand experience of many different owners. In all 15 threads, the main question was "How long should a motorcycle clutch last?" There were many replies related to why clutches wear and how to prevent it, but 80 riders of different types of bikes shared their own experience of how long their clutch actually lasted. Only 24 riders had to replace their clutch after an average of 19 894 miles. One rider had to replace the clutch basket after 10 000 miles and 2 riders replaced the clutch springs at 26 000 and 65 000 miles respectively. The remaining 52 riders (65%) shared their current mileage on their motorcycle clutch which is still in good condition after an average of 60 864 miles. Average(miles)Maximum(miles)Minimum(miles)Current clutch60,864+200,000+12,000+Clutch kit*19,89460,0001,200Clutch basket*10,00010,00010,000Clutch springs*38,66765,00025,000* Replaced due to being worn The average figures are misleading due to the very large variation in the individual accounts. Two riders with exactly the same motorcycle would report very different lifespans of their original clutches. One example is a KTM 990 Adventure rider replacing his clutch at 7 000 miles due to a clogged oil jet, while another 990 rider did well over 60 000 miles. Not all bikes have the same clutch types, but there are accounts of clutches lasting more than 50 000 miles on sports bikes, tourers, cruisers and adventure bikes. Different Type of Clutches and How They Work This is not an engineering article, so I'll try to keep it simple. The power from the engine needs to be transferred to the gearbox somehow. This is done via the clutch. Some bikes have dry clutches that work similar to a car's clutch. Most modern bikes, however, have wet clutches. In a wet clutch, a series of friction plates (the clutch pack) rotate together. A wet clutch system is common on most modern bikes Half the plates are driven by the engine and every second one is attached to (and drives) the gearbox. Very strong springs push them together while the clutch lever is left alone (fully out). Wet clutches are bathed in engine oil to keep it cool. Since the clutch plates have friction material on it (almost like sandpaper), they rotate in the same direction and at the same speed when pressed together. In order to cut the engine power to shift gears or come to a stop, pulling in the clutch lever releases the tension on the clutch springs. The clutch plates can now rotate freely at different speeds and no power is transferred. Every time you pull or release the clutch lever, there is a short period when the plates are not fully free of each other, but also not fully engaged. This is referred to as the friction zone where the clutch plates are slipping against each other. It is similar to rubbing two pieces of sand paper together. While clutch friction plates are much more durable and designed to be slipped, it is not hard to see why slipping the clutch would cause it to wear over time. All clutches wear down. Depending on how you ride, this could be thousands of miles, or ten thousands of miles. Quite a few riders said they had to replace clutch springs long before the friction plates wore out. This would become noticeable if the clutch start slipping, but the plates are still fine. A solution is to fit stronger, aftermarket clutch springs like these from Barnett (a brand many riders swear by). You can conveniently buy them from Amazon. Why Does a Motorcycle Clutch Wear? Clutch discs work almost like brake pads. The friction between the plates is what makes the engine drive the gearbox. Each time you pull or release the clutch lever there is a point where the discs are slipping against each other. This wears the friction surfaces down over time. The longer the clutch is allowed to slip in the friction zone, the hotter it gets. Hotter clutch plates wear faster. In order to cool clutch plates, wet clutches are submersed in engine oil. This means that the fine dust coming off the friction plates will contaminate the engine oil. Luckily the oil filter will catch most of it, but it is still very important to not skip an oil change. Normal wear When you pull away on a hill or on a motorcycle with a tall first gear (like a sports bike), you need to slip the clutch a bit more to pull away smoothly. While this will wear the clutch over time, it is considered normal wear. Motorcycle clutches are designed with this in mind. At crawling pace, like in slow traffic or a parking lot, you may need to feather the clutch (in the friction zone) to trim power in order to prevent it from stalling when the engine speed (rpm) drops too low. While not ideal, it is normal and won't harm your clutch. Slipping the clutch at high rpm is much worse than at low rpm. Poor maintenance Many motorcycle clutches are cable operated (as opposed to hydraulic). The free play in the clutch lever needs to be adjusted regularly as the cable stretches. A cable that is too tight will be permanently tugging on the clutch release fork, releasing the spring tension and allow some slipping and increased wear. A slack, stretched cable won't allow you to fully disengage the clutch when pulling in the lever. Again, this will allow the plates to slip with the lever fully pulled in, which will increase wear. Accelerated wear Anything that causes the clutch plates to slip in the friction zone for extended periods of time or at higher rpm will cause excessive clutch wear and premature replacement. Examples include: Popping wheelies by dropping the clutch while rolling on the gasDrag-starting the bike by revving the engine and slowly letting out the clutch (it is much worse doing this in a higher gear)Doing doughnuts where slipping the clutch is necessary to brake tractionDown-shifting without pulling in the clutch and breaking traction with the rear wheel (some riders disagree, but mentions that the shift forks can bend)Slipping the clutch to trim power in sand, mud or snow (this is a common practice of adventure riders and considered by some to be normal riding practice). How you ride will largely determine how long your clutch lasts On some smaller 2-stroke motorcycles you need to slip the clutch often to get going, especially up a hill. Dirt bike racers also use their clutch extensively when pulling away at the start line. They often start in a higher gear while slipping the clutch in order to prevent lifting the front wheel and flipping over backward. How to Make Your Motorcycle Clutch Last Longer The two main things that will make your motorcycle's clutch last longer is the way you ride and how you maintain it. Riding style If you want to make your motorcycle clutch last longer, avoid slipping the clutch, especially at high rpm. It is normal to slip the clutch a little when you are pulling away, but as soon as you are moving release the lever all the way. When you slow down to stop, rather shift to a low gear instead of holding in the clutch. If you are going to do clutch wheelies and drag starts, prepare yourself for a premature clutch replacement. Maintenance Change your engine oil regularly to get rid of contaminants from the wearing of the friction plate. Fresh oil will keep a wet clutch cooler, and therefore last longer. Don't use normal car oil, as some types have friction reducing agents in it which might make your clutch discs slip. Make sure your clutch cable is adjusted properly and that the cable moves freely. The clutch lever should have the correct amount of free play as per the owner's manual to avoid the clutch slipping all the time. If your motorcycle has a hydraulic clutch, check the fluid lever regularly and top it off if it is below the minimum mark. Adjust your chain tension at regular intervals. If the chain is too tight, it could wear the clutch faster. When the chain develops tight spots, replace it as soon as possible. On some bike, like the KTM 990 Adventure, you need to ensure the oil jet in the clutch assembly is not clogged. If it is, the clutch will run dry, overheat and wear much faster. How Do I Know My Motorcycle Clutch is Worn A clutch usually wear out over time. It is unusual to simply go without notice. When the friction plates are worn the clutch will start slipping. You will notice the engine speed rising as you add throttle, but nothing happens to the road speed. This means that the engine power is not transferred to the gearbox. This will be more acute at higher rpm or accelerating fast in a high gear. If your clutch is still fairly new and it starts slipping, particularly after an oil change, it may be running on the wrong oil. Simply change the oil to the recommended type for your bike and it should be okay. In some cases I've found that the clutch springs (that press the plates together) lose their tension before the clutch discs are worn. This will also cause the clutch to start slipping as the friction between the clutch plates are not enough to transfer the power from the engine to the gearbox. Sometimes the clutch springs need replacing long before the friction plates I've also heard of clutch baskets, the cage within which the clutch pack sits, that break. If you hear a clunking noise from your gearbox area, stop immediately and get it inspected. Some of the fingers of the clutch basket may have broken and you don't want it to get into the gearbox to cause major damage. Luckily a clutch replacement is fairly straight forward on most motorcycles, so if yours is on its way out, start watching YouTube videos on how to replace it yourself. Final Thoughts All clutches wear out over time. Motorcycle clutches are designed to be durable and it is considered normal to slip the clutch in various situations. The less you slip the clutch in the fiction zone the longer it will last. If you keep the clutch lever free play within spec and don't abuse your clutch, there is no reason why it can't last as long as the rest of your motorcycle. Related Questions How bad is it really to 'ride the clutch' on your motorcycle? We've chatted about riding your clutch and how it wear the clutch out faster. To read more on when it is necessary to ride the clutch, read this article I wrote. Are you stopping your motorcycle the correct way? If you are a beginner motorcyclist and unsure whether you are stopping your bike in the correct way, read this post on how to smoothly stop a motorcycle.