Post
by Salt Lake K5 Guy » Tue Jun 02, 2020 6:57 am
I was looking for some advice on how to get a Rekluse Radius X set up correctly when I found this post. I have a bit of advice on a stock KX500 clutch though. (Even though I have possibly put one together a little wrong once or twice myself though.)
First, the KX500 clutch, in its stock form, is usually more than beefy enough to get the job done! (Usually)... That being said, most of the clutch kits out there for it are comprised of what “appear” to be beefier friction plates, and come with stiffer springs. Much stiffer. The steel plates are also of a different hardness. Those first two things both affect clutch pull to a great degree! They can also affect how the clutch behaves during heavy feathering as well as winter operation. There is no perfect clutch, but most K5 owners have to admit this one fact; they don’t wear out quickly, and they don’t fail often. Usually neglect is the cause of degradation. If you don’t remember how good the original clutch felt, it will cost you quite a bit to go all OEM, and good luck finding a new basket!
Second, it’s mainly about the cable. At least as far as smoothness goes. Smooth is easier. Easier is lighter. Lighter is good-er. I have had good results with OEM, Motion Pro, and Moose. My favorite was a TerryCable, back in the day. If you can find one of those in working condition though, you should get into alpine narwhal hunting, because you are either lucky or good! The biggest issue with the cable is routing though. A lot of people try to send it down the headset, and then across the front of the engine, then into the bend. NO! Too many direction changes. The only good way is out of the perch, across the top of the top number plate bolt, then a sweeping and descending left heading around the. FRONT of the frame down tube (just behind the front fender. It will possibly rub a little) and then the formed bend will head through the exhaust pipe bend, but not touch it. This results in no direction changes. Just a single continuous curve. I have also used a cushion clamp to hold it still, attached to the top right radiator mount bolt. This minimizes the change in feel when the handlebars are off center. This will result in a lot less cable friction.
Third, not all levers are created equal! There are certain lever geometric designs that result in more or less leverage. More leverage is lighter, but it moves the cable a shorter distance. There are those that do the opposite though. Either have detrimental effects. These levers are all designed for smaller clutches than the 5hundo. (It makes little difference though). The real difference comes at the bell crank. That is the lever in the case that pushes the clutch push rod. If you look at it, the end game of that lever is just a flat spot on a shaft. The flatter that spot is in relation to the push rod at the start of actuation, the harder the pull will be, but the movement of the push rod in relation to the movement of the hand lever will be the greatest. This also corresponds to the least compression of the clutch springs at the beginning of the pull though. As the bell crank transits through its arc, the flat spot becomes perpendicular to the end of the push rod, which gives it increasingly more leverage, but less travel in relation to the hand lever. When you go to a new clutch pack, or wear one out, the overall depth of the pack changes. This moves the pressure plate, which in turn moves the push rod. This greatly effects the angle at which the bell crank begins to actually move the rod, And thus how hard the pull is, or how far the pull travels the rod, this can be adjusted using shims under the throw out bearing hat. I have seen people attempt to lengthen the portion of the bell crank where the cable joins in an effort to reduce pull force. It does that, but also makes the clutch drag because it doesn’t disengage fully. It’s like only pulling in the clutch lever half way. Don’t do that mod!
Anyway, these are just things to consider when monkeying around with clutch geometry. The biggest thing to consider with almost all aspects of the KX500 though is to just realize that it wasn’t meant to be ridden by a little measly girlie man, and if the clutch is too hard to pull, then it’s either in bad shape, or you are!
Just my 2 cents...
Brent.
