What is slugging a wet clutch?
The kit works on 660 Grizzlies, 660 Rhino’s for the one kit and the 700 Grizzly, 700 Rhino, Wolverine and Viking in the other.
Before we get into the tech article, I highly suggest getting the optional wet clutch nut. The nuts holding the wet clutch on are designed to be one time use. One they have small fine threads and two they have a lip on them used to peen down on the flat spot on the crank to keep it from coming off. Some have reused it with success but I personally am not risking it over a $10 nut. The 700, Viking and Wolverine are left hand threads and the 660 is right hand.
Slugging a wet clutch is adding weight to the shoes in the wet clutch to increase gripping strength of the wet clutch to help eliminate slipping under heavy loads and destroying $600 worth of parts plus labor in the process!!!
Who needs it? In my opinion, every Grizzly, Rhino, Wolverine and Viking owner to extend the life of the wet clutch. All Yamaha Viking and Wolverine owners due to weight of vehicle and not enough wet clutch clamping power. The person who needs it also is anyone with heavy loads such as really large tires say 28” and above, the guy who does a lot of low speed driving like rock crawling or pulls heavy loads with their ATV/UTV. Really low RPM and speed has the least amount of wet clutch grip again due to centrifugal force. So adding the weight makes it require less force to get the wet clutch to grip.
What is a wet clutch? A wet clutch is the clutch inside the engine that works off centrifugal force. As you sit and idle, the shoes stay at rest, as you increase RPM they fly out and grab the drum portion of the clutch. If you have ever seen a clutch on a chainsaw, go cart etc it looks more or less like that and works just like that. The primary external clutch rides on the shaft that is attached to the drum portion in the engine.
The slugs add weight to the shoes so it takes less force and less RPM to get them to sling out and grab the wet clutch vastly improving low speed performance, without them the wet clutch slips and wears the wet clutch out quicker.
The old idea was to use stiffer springs in the wet clutch to raise RPM up so as to have more engine power before the tires started moving. That idea has several flaws. The major one is, stiffer springs tries to pull the shoes back therefore not having as much grip, causing more slippage and faster wear with higher heat. Also, since it creates a stall RPM then if high enough the weights in the external clutch will start moving out, pushing the belt up the sheave and basically putting it in a higher gear to start off with. All of these are bad ideas and not sure where it got started. We have never recommended stiffer wet clutch springs except in one isolated case, my own rhino where I raced cross country with engine mods that the power was higher in the RPM range. We had dead engine starts so as soon as I cranked it I would floor it and it would bog for a few feet. Raising my RPM helped that. I did not have heavy loads though and again this is the only one time I can imagine it being good. NEVER USE WET CLUTCH SLUGS AND STIFFER SPRINGS IN THE WET CLUTCH. THE SLUGS ARE FOR USE WITH STOCK SPRINGS ONLY!!! IF YOU HAVE STIFFER SPRINGS THEN PUT STOCK SPRINGS IN WET CLUTCH WHEN YOU INSTALL THE SLUGS.
When you couple the wet clutch slugs for lower engagement RPM with our machined sheaves where the belt rides lower in the primary and higher in the secondary then you get much better take off and low end performance because you GET full lock up of the clutch while the belt is in its lowest position meaning lowest gear for best low end power.