So the Black Butte has been in build stasis since mid-March. It performed admirably in Nashville, besides pretty drastic temperature issues. On the long, hilly, Saturday ride I was having to back off the throttle constantly due to hitting 425F far too often. This was causing serious heat fade as well, which I can tell you is very real and very annoying. My timing was as retarded as I could make it without completely eliminating low-end performance, and my jetting was definitely on the rich end. So my plans are some piston mods and continuing to lust after an ignition with an actual, you know, TIMING CURVE.
Another major issue was the low end, which wasn’t to the point of wretchedness, but certainly sucked for a Hobbit with pretty strong clutch springs. It almost felt like the clutch was slipping like a Puch, which definitely was disheartening, and made me worried about the porting Devin did for me out at MLM. An advanced timing would certainly help out, but would cause even worse heat issues up top, so I didn’t want to mess with it.
I decided to address this issue by getting the absolute strongest clutch springs I could find. A reasonable and well-thought-out approach, yeah? I also purchased a beefy set of circlip/snap ring pliers with a bunch of swappable arms. These give you the ability to stretch out the spring using leverage. The Hobbit clutch doesn’t have a really nice variety of leverage points to work from, but with the right tips you can JUST get the springs to catch on the edge of the hole and then smash it in with some taps from a hammer. I first put the medium springs in one spare clutch, and after I figured out the technique I got the three strongest springs in by myself in 10 minutes or so.
So the initial tests were definitely BETTER, but it was still slipping and not really launching me the way I wanted. I got to thinking and realized maybe the inside of my clutch bell had a bunch of glazed pad material on it, so I pulled it, sanded the inside surface down, sanded the clutch pads, and put it all back together. Holy crap, what a difference. The clutch grabbed hard at some stupid RPM and the front wheel came up a little even with a bunch of my considerable bulk pressing down on the bars. It’s borderline unsafe. I didn’t test much besides a few parking lot revs, due to increasing darkness and my fear of ending up on the side of the dark road due to an unforseen 45mph wheelie.
I think I can now try to use the St-Ripper again, as I might be able to launch right into the pipe, or close to it at least. If it wasn’t raining, and I wasn’t leaving for the weekend, I would do that IMMEDIATELY. Devin also has a few new pipes for me to test and will be giving them to me at the Thunderdrome races at the end of this month.
So current status: hitting 61.5 or so with my 195lb self on it. My much lighter friend Ryan gave it a spin last evening and hit a ridiculous 64.5. I need to lose some weight.
Next steps: weak-ends rear pulley mod and stiff spring installation, pipe experiments, wheelies.