WERKS Parts LLC
CLUTCH FRICTION AND STEELS WEAR
I don't often recommend replacing the friction plates in the DL and SV 1000 clutches when upgrading to a WERKS modified clutch basket. They always tend to be well within service specifications for thickness. There are however circumstances that might promote the need to replace them. Probably more often seen in SV 1000's that are used hard or not maintained well, or DL 1000 that get really abused in tight off road conditions often.
Below are some words from Michael Schmidt. You may know him from the forums as "schmidt314". He builds some high horsepower SV and DL engines and has run into some special circumstances.
"I rarely see a clutch plate get to the wear limit (Maybe never), but I replace bad clutches all the time. If the plates over heat and or get glazed they loose their grip even though they are at the new thickness. Incorrect oil will embed "Friction Modifiers" and this will also waste a clutch in a hurry.
"Clutches will last quite a bit of time if treated well with good oil as others have mentioned. In my personal commuter SV1000, I have never flat worn a clutch out until it was slipping. I have only replaced them as preventative maintenance.
What I do often see when the clutches start to chatter or have strange engagement behavior is slightly glazed frictions plates and/or a jutter spring that has worn into the mating steel plate. the jutter plate will dig a bit of a groove over time and will not work to spec. In these cases I dismantle and inspect everything to assure the plates are not broken, warped... If all good I gently Scotch-Brite the frictions and steels to deglaze them. Then I swap the steel plate that rides against the jutter spring that can get worn. I have piles of spare plates laying around, but if not, clean and debur the plate and swap it position with another plate in the stack. This will let the jutter spring pull up slack earlier as the clutch pressure plate start to apply pressure to the stack.
There are many details that go into building a WERKS modified clutch basket. All clutch baskets go through an intense cleaning process before machining and again before assembly of finished parts. Parts are inspected at each stage of fabrication. With the addition of the second bearing, the assembly process requires jigs to align the parts so they function properly. All internal surfaces are coated with synthetic 75-90 weight gear oil during assembly. No additional lubrication besides some on the teeth of the steel gear is recommended. High strength fasteners replace the factory rivets. These are locked in place using quality thread locking compounds.
WERKS Parts LLC reserves the right to change specifications and materials at any time. We are always looking for the best way to build our products.
The basket castings have a very rough finish around the anti-balloon band. Sometimes there are high spots with enough material to effect the balance of the basket slightly. While in the lathe for boring to fit the bearing the basket is turned just enough to remove the high spots and smooth out the rough casting marks.
Once the inner plate is locked to the aluminum basket all the force from the springs is transmitted directly to the basket and then onto the clutch plates. No lost motion from the inner plate moving back and forth as the engine power pulses load and unload against the springs. This means the three stages of spring damping can work like they are intended to work to control vibration from the engine. All the load is now carried by the springs. The steel gear is less likely to hit the aluminum posts in the basket, which is a harsh event at best. The three stages of damping in the basket can now come in progressively and give that controlled refined feel the WERKS modified clutch baskets are known for!
This is the inner plate fitted with three machined bushings to locate it properly to the basket. From here it is machined to fit the aluminum basket to mate the two parts permanently.
This picture shows how the inner plate and spring can embed into the aluminum basket over time. The steel gear actually hits the posts in the basket now!
Once locked into proper position you can see how the edge of the steel inner plate overhangs the edge of the aluminum basket. The springs and plate can no longer embed into the aluminum when the inner plate is locked to the basket.
Next up is the troublesome "inner plate". This is the main source of vibrations known as chudder. The six springs of this damper assembly push against this steel plate. Or are supposed to. Once the baskets have only a few thousand miles on them this plate can already be shifting enough to allow the springs to embed into the aluminum basket! This gets progressively worse as miles add up until the steel plate is not taking much load from the springs. This allows the steel plate to oscillate back and forth till the springs hit the aluminum. This is the source of most of the noise from a worn clutch basket. The big problem is that while this plate is moving back and forth taking up slack in both directions it is NOT absorbing load from the springs and transmitting it to the basket! This slack amplifies the force of the springs hitting into the basket in both directions and sets up an uncontrolled back and forth movement known as chudder.
The driven gear ( big steel gear ) bearing surfaces are not machined to a smooth finish at the factory. This can be felt by running a fingernail across the bearing surface and it will leave grooves in the aluminum as it embeds into the basket. The WERKS build process includes re-machining the main bearing surface, as well as the added second bearing surface, to a nice smooth finish that won't eat into the bearing surfaces.