Maintaining your secondary clutch
|One of the easiest ways to restore or improve the performance of your sled is to make sure the clutches are working at their peak performance. In this article I will cover working on the secondary (driven) clutch for Polaris and SKI-DOO sleds and the goal of this article is to help you maintain your stock clutching and/or help you install a clutch kit that contains parts for your secondary clutch.
First step is to remove the belt from the sled.
For a sled without electronic reverse:
For a sled with electronic reverse:
First thing you will want to invest in, or borrow, is a clutch press tool. I have one similar to this SLP model and it has become one of my favorite tools, as it makes working with clutches very easy:
Next you will want to clean the helix. Some models have helix that have a coating on them and you will want to be careful to not damage it. This helix doesn't have any coating so it's very easy to see the dirt on it.
The helix is a very important part of the clutches because all of the power that is created by the motor will be applied to the secondary clutch via the buttons, or possibly rollers. Assuming that you are going to use the helix you removed from the sled you will want to clean and polish the helix ramps to a mirror-like shine so your clutches can react as quickly as possible. The outer surface of the helix should also be cleaned and polished to aid with this. Note: if you are installing a clutch kit that contains a helix you don't have to worry about cleaning the stock unit.
Next, clean the inside of the movable sheave. This will include taking any belt dust off of it and any grease that is on or around the brass bushing on the sheave. Once it's cleaned, inspect the large bushing on the outside of the movable sheave. It's a copper bushing with a coating on it and if you're seeing more copper then coating it's time to replace. To replace it, remove the screws that are holding the bushing in. Then use a brass drift to knock the old bushing out. Clean the surface and then pound the new bushing in and replace the screws. If your clutch has a set of buttons inside it (as opposed to rollers) you want to inspect them for wear as well. If they are worn down use a set of long nose vice grip pliers to pull them free.
They can be brittle, and if they break off while pulling them out then insert a small wood screw, (#4 1" long work well) and then pull them out by the inserted screw
Springs are wear items, like belts or brakes on a car, eventually they will need to be replaced. A good rule of thumb is to replace them every 3 years or 3,000 miles. Sacked-out springs will impact performance so this is the first place I turn to after inspecting the belt. Worn out springs make your sled feel like it's stuck in high gear all the time, so it won't have as much power and snap as it should. The easiest way to check the spring is to measure its free length (un-installed length) from charts available from the spring vendor. The springs in older style clutches tend to have tines or ears on them and if they don't align then that's another sign that the spring needs to be replaced.
Before assembling the clutches you wan to lightly grease the shaft on the fixed sheave. This will allow the movable sheave to easily slide up and down on it while you're riding the sled. Once you place the movable sheave on the shaft, check to see if it binds. If it does, that will affect performance and the sheave will need to be sent out to have the bushing replaced.
Assembling with a spring without tabs:
Assembling with a spring with tabs:
Clean the clutch faces with acetone to remove all grease, oil or other contaminants and then install the clutch into the sled. Wrap the belt around the primary clutch. If you used a small clutch tool to remove the belt, install it now and install the belt. Otherwise rotate the movable sheave 1/4 turn and push the belt down in between the clutch sheaves. This will create the length in the belt so it can be spun around the rest of the secondary clutch. When installing the belt be sure to install the belt so you can read the numbers off it.