Clutch Cleaning and Maintenance
There are several methods discussed across the karting community as to the proper way to clean a disc clutch. After going through the sheer number of clutches that we have to date, we have found what we suggest as a proper cleaning and maintenance of a disc clutch that is pretty universal. This is only a guideline to what we have found works. For each step, we will explain why we do this procedure. This is a lengthy article, but I feel the need to address things in detail.
The clutch we are using as an example is one of our own two disc Hybrid clutches. I highly suggest getting a small box or something to put all of the parts in. You will need a rag or absorbent paper towels, WD40 or Liquid Wrench, and preferably compressed air with an air nozzle.
∑ Begin by first taking off the clutch basket by removing the small snap ring at the front of the clutch driver. Behind the driver and basket assembly there should be a set of washers and a thrust bearing (a flat roller bearing). Sit those aside until later with the snap ring and any other washers/ spacers. Look at the clutch basket for cracks, and wear in the driver hole that may cause it to be sloppy. Inspect the driver bearing for any slop or play and replace if worn or damaged. Inspect the thrust bearing for missing rollers, or damaged rollers and replace if necessary.
Remove the clutch driver from the basket and place it to the side. Spray the basket liberally with WD40 or similar and sit it aside to soak. Using break clean, spray the driver gear out clean, then allow it to dry. Once dry (a few seconds) spray it with WD40 or liquid wrench and sit aside with the basket.
∑ Now we move on to the clutch itself. Many times people will say it needs to soak in acetone or a degreaser. We have tried this method and were never satisfied with the results. The reason it doesnít work is that there is nothing agitating the dirt and clutch dust that gets into the tiny pores of the friction disc material. Itís similar to putting your clothes in the washing machine with soap and water, and the washer never moving. They just sit there and soak and never get clean. The proper way we like to use is when the clutch is completely disassembled, and use a tooth brush with dawn dish detergent and hot water to brush the clutch discs clean. Many times the complete disassembly is not viable, so we move to the next best thing which is compressed liquids.
I first suggest using an air nozzle to blow any loose dirt from the clutch. Position the clutch so that the driver journal is pointing down, and the levers/ springs are pointing upward. This will allow any dirt or grime to flow out of the clutch instead of into the lever pins. Spray the discs and area between the discs/ floaters only. Spray them liberally trying to directly spray the friction discs as much as you can. Once this is done, blowing the clutch out with an air nozzle is preferred but not entirely necessary to completely dry it off.
∑ Next we focus on the back spring / lever side of the clutch. If itís very dusty blow it out with an air nozzle and if itís dirty, use a long bristled brush to work any excess dirt off. Once the dirt has been brushed or blown away, wrap a towel around the discs so we donít get any lubricant on it as in the picture. Lightly spray the back side of the clutch with WD40 or Liquid Wrench. You want to coat it, not soak it. Once itís sprayed down, lay a dry towel or piece of cardboard down and lay the clutch lever side down so any excess lubricant flows down and gets wicked away by the towel or cardboard. Itís preferable to let this sit over night.
∑ Returning to the basket, wipe it down with a clean dry cloth and spray again if you have some stubborn dirt. We want this to be free of all grime and dirt. Harsh chemicals should not be necessary to clean the basket. Wipe any excess lubricant from the clutch driver and reinstall. The clutch driver just gets a dab of high temp bearing grease. We know clutch manufacturers sometimes recommend Vaseline, but the melting point of Vaseline is low at 165 degrees and that means it will soon be all over the inside of your basket and clutch. Vaseline is not a high temp lubricant and should be used on dry cracked skin, not high performance clutches. Red high temp grease will still burn off if it ever makes itís way into the clutch discs. The issue with that is, if itís high temp it wonít melt. If it doesnít melt it wonít bleed out into the rest of the clutch. Makes sense huh ? It stays where you put it.
The thrust bearing and washers should be sprayed down with WD40 or Liquid Wrench and wiped clean. There is no need to grease this thrust bearing, but if you feel the need, a very, very light coat of grease will work. We generally do not grease ours and only use lubricant while cleaning.
Reassembled the driver and basket on the clutch, and youíre ready to hit the track again !