KTM / Husqvarna 50 Heavy Duty Clutch Springs
As every Mini Dad knows clutch issues are an everyday pain in the neck. The question is how can you make your 50 clutch perform at its peak and last longer?
Nihilo Concepts is known for innovative products and solving the problems that can happen on OEM equipment. The KTM and Husqvarna 50’s have centrifugal clutches, which means they are activated by centrifugal force or the spinning on the motor. The manufacturer is trying to provide a lot of performance in a very small package and that is why we see clutch issues on these powerful little bikes. On larger bikes, it’s easy to make strong springs because there is more room under the clutch cover. The high performance 50’s are very powerful but there is not enough room in the clutch assembly to provide a strong enough spring to eliminate clutch issues.
Now first it’s important to understand the way these little clutches work, with larger bikes (with conventional clutches) the clutch springs are designed to apply pressure to the clutch plates and create drive to the rear wheel. This is why it’s always a good idea to install aftermarket Heavy Duty clutch springs on these types of clutches, they help eliminate slipping and create positive pressure helping the clutch perform at its best.
Now the small 50cc automatic clutches actually work in the exact opposite way. The clutch springs on the 50’s are designed to hold the clutch back from engaging until a high enough RPM has been reached to facilitate clutch grab. In other words, the clutch is in the open or non-gripping position until the motor spins up to a high RPM allowing centrifugal force to engage the clutch. The spinning clutch has internal balls that fly outward on ramps and apply pressure on the clutch plates. This system provides plenty of grip at high RPM, so unlike the conventional clutch, 50cc clutch springs are not helping with clutch grab but instead pulling the clutch apart and eliminating grab when RPM’s come down. If there were no springs in these clutches the balls would fly outward immediately and bog the motor down. The springs are designed to hold the centrifugal action back until the motor hits its power band and is able to absorb the weight of rider and machine and create a smooth launch without bogging.
Every 50cc clutch part that Nihilo Concepts makes is designed to hold the clutch back so it fully engages at the perfect time which is the exact moment that the motor hits its power band and is revving at approx. 8000 RPM’s. These clutches will last the longest if they are either fully engaged or fully dis-engaged. It’s important to teach your young rider to try to ride these bikes either full on or full off the throttle. By doing this you will eliminate as much slipping as possible and your clutch will last much longer. Another benefit of riding with this technique is there will be less heat from the clutch being transmitted to the rest of the motor, helping with general overheating and stator issues caused by excessive heat. The bottom line is life gets a lot better if you eliminate unwanted slippage and friction.
I always suggest that you take your rider to a big open field and have them practice holding on the gas until the clutch grabs and then not backing off. With most kids, the hard hit initially scares them and they instinctively back off, this will cause a herky-jerky style of riding and create excessive slipping and heat to the clutch. You will find if they get used to the initial hit of the clutch they won’t need to back off because they will be used to it. It may sound like a hard thing to teach but I’ve seen it work a hundred times. When they realize the hard hit of the clutch is not as bad as they thought they gain confidence and become better riders. Doing this in a big open field allows them to concentrate on the clutch while not worrying about a turn or obstacle. It’s better for them to ride like this than to be hunting for the perfect speed out of corners because with this type of clutch, they will not find that perfect grip until they are going pretty fast. I could spend a whole chapter on this technique and perhaps we can talk about it more in the future blog, but give it a try. I think you will be glad you did.
Nihilo’s Heavy Duty Clutch springs for the 2013-2020 KTM / Husqvarna 50cc bikes are wound from a higher quality spring wire of thicker gauge and are a little taller than the stock springs. The thicker better quality wire will allow them to last much longer than the OEM springs. The only way to make any constant wound spring stronger is either by using a thicker wire, adding more coils or making the diameter smaller, with this spring we could not wind them smaller so we added more coils and used thicker wire, they are taller than the stock springs as well. You will find that the adjuster will work best at 2-4 clicks with the Nihilo springs. Over time if you feel they are fading you can add a click or two to bring them right back to life.
By: Bob Brewster Riding and wrenching on dirt bikes since 1968