Most parts on a dirt bike have manufacturer's recommended intervals in terms of when to replace so you ensure uninterrupted optimum performance.
The clutch, however, varies widely and no set timetable exists giving you an idea of when to change out the drive plates, pressure plates and clutch plates. Aggressive riders eat clutches like candy while others get 20 hours or more, and racing Supercross burns through a clutch far more often than a trail ride.
The more experience you get on the bike followed by routine clutch changes gives you an idea of the average rate of return for a new clutch. But replacements get expensive and take time thus most riders generally ride the clutch into the ground, or at least close to it, before making a change.
Unfortunately, when the clutch fails it no longer grabs to give you forward movement. So even though you change gears the bike basically remains in neutral. Therefore, waiting too long can leave you stranded or spending time replacing the clutch while everyone enjoys the ride. But, getting the feel of the symptoms that indicate a forthcoming bad clutch allows you to make the necessary parts replacements before you get left standing still - because that's what happens when the clutch fails.
How To Tell if Dirt Bike Clutch is Bad
The most obvious sign to a failing clutch happens when the gears slip. You will notice this when the bike holds the same speed while you click up gears. The engine sounds normal and the bike moves but a pinned throttle does little more than run the piston up and down to no avail.
Try grabbing the holeshot when the clutch slips.
If you suspect a slipping clutch smell the motor oil after a few laps. If it smells burned, the clutch has probably been slipping and you need to replace it.
Notchy Clutch Pull / Engagement
When you press the clutch lever, it should feel smooth like a hot knife through butter. If it clicks or feels like it passes over notches you have limited time with a functioning clutch. Or, the lever easily pulls in but causes the bike to lunge forward. This indicates an issue with the clutch basket and/or pressure plate because the clutch plates catch on worn areas (or notches) of the basket or pressure plate.
Generally, you can still operate the bike and change gears to ride but you need to replace the clutch pack much sooner rather than later.
A burning clutch has a distinct smell and normally occurs from aggressive riding. Think about this: Some pros need a complete clutch replacement after one Supercross race. Some people say a burning clutch smells like burned brakes or a mix of burning oil and rubber or a combination of all three. Regardless, you can typically differentiate a burning clutch from any other smell emanating from your dirt bike.
If you burn the clutch, that doesn't necessary mean it stops functioning. You have certainly worn down the clutch fibers on the clutch plate and if you catch it early you can probably continue riding for the day. But you have caused irreversible damage and shortened the lifespan of your clutch so we advise inspecting the clutch plates and pressure plates when you get home.
Clutch Cable Adjuster
The thumbwheel or cable adjuster for the clutch lever allows you to tighten or loosen the clutch lever pull depending on your preference or need. Eventually, the thumbwheel runs out of room, so to speak, and no longer adjusts the cable tension. Once you have reached this threshold, the clutch on your dirt bike has started circling the drain.
Symptoms of a failing clutch may set in gradually or suddenly, and often only one presents initially but if left unattended expect the others to follow. As soon as you experience any one of these symptoms you ride on borrowed time. You may get away with a failing clutch for a day but at some point the bike just stops moving.