Less than a week to go until MAC and so far my clutch is still not holding up. The more I try to make it "right", the worse it gets. I know what the problem is but damned if I can afford to fix it properly. So, going to hack it even worse and cross my fingers.... Worked the first time!
The clutch made it through yesterday but still slipping some. 2nd to 3rd followed by pinned throttle is guaranteed slippage. Still, better than previous iterations! This was built using a mix of PK and PV plates and a thick steel in the middle.
My clutch held up for the last part of the race day, after taking it apart 5 times. ( Big thanks to Patrick for helping me to figure it out. ) Some things I learned: XL2 clutches take a lot of work to get to fit right. you need to ditch the oil slinger with the drt top plate. xl2 bearing pressure plates are too tall fro some clutch covers. Putting two metal plates together makes your clutch do funny stuff. I don't think clearly when tired, hungry and frustrated. I am just glad I got to take the bike for a few successful rounds. Great time this weekend!
Heh! My clutch didn't 'start' to give way - it took a vacation while I was entering the back twisties. I was waiting to see if anyone caught it on film. Rear wheel locked up @ pretty good velocity even w/ the clutch pulled & pitched me ass o'er teakettle. Thankfully, my gear really does save my ass. All that flopping about on the bike & pavement - all I got was a smashy thumb. Nothing that doesn't happen @work. The clutch aftermath:
Testing out a new version of my clutch and so far it's holding. This was day 4 on this clutch...actually I changed 2 plates after the first race weekend but only because I was paranoid. Anyway I tried to trash it last Sunday slipping it, riding like a madman etc but it kept holding in fact it's still holding! If there was a track day or non points race coming up I'd run it again...but I'm going to take it apart and put fresh plates in... again just because I don't want anything to go wrong on race day.
The magic formula (for me anyway):
4 Polini Aluminum Friction Plates PV style .89mm plain plates DRT top plate 8 stiff springs with an adapter of my own design to get them to fit into the PV style clutch.
I'll be taking it apart to have a look and will post up what I find.
Update: So after a season of racing and a much more powerful engine the clutch has held up. I did change the plates several times throughout the season out of paranoia but for the last 5 or 6 races I haven't touched it. I'm not easy on clutches. I slip it in pretty much every corner to stay in the narrow power band of my motor so for it to last this long is a major accomplishment. So I've made a few copies of my spring holder system, but before I order a whole bunch of springs for them I thought I would post here to gage interest.
So does anyone want one? The price would be $25 for the holder and 8 springs plus shipping which would be pretty cheap due to the weight. You would still need the plates and DRT top plate but if you are not running an XL clutch I think this is a viable alternative.
Racing is fun. Building bikes that go fast? Also fun. With all of the fasty fun parts available right now, there is a lot of power to make & be had. If you are consumed with the idea of making something really powerful - there is no maybe on whether or not you're gonna drop some scratch on a clutch. Yep, I got a 54/105 60mm Falc. I put a little extra work into it, but nothing really crazy.
1.5 days at the track in Canada = 5 sets of clutch plates.
You can see the 8 red stiff spring DRT piece. This worked pretty well last year with 5 plates. We even engineered a means of getting 4 more springs in that one. Yes, I've gone the 12 spring XL2 clutch route previously as well - same effect. Spendy couple of days for me. Maximum useage time? 5 laps.
That day we ended up pioneering a piece of fun stuff from my good friend Dayn - he made this insert that holds 14 very stiff springs. Heavy duty as it is, the XL2 clutch cover makes this monster not too tough to pull.
Sadly, it would not hold either.
6 plates? 14 springs? Suuuuure...
It did fit & it did work... But only for a couple minutes. Onward & upward.
Had been using Silkolene Pro SRG medium weight (with decent success). That got discontinued, so under recommendation from my local rep, I tried the Maxima equivalent & didn't like it. Now I'm back on the Silkolene medium weight race stuff specifically designed for racing 2 stroke clutches. Know of something better?