Chapter 9 - Small Things and First Test Ride
With the footrests done, there were plenty of other little things that got worked on to get it ready for a first ride. Stuff like adding an anti-rotation tab for the rear brake plate, as well as a cable mount/stop onto the brake plate itself. Nothing fancy, don't think I got any pictures of that.
Got the throttle mounted to the bars, realized I needed better spaces for the cheapo clip-ons from Treats. The General fork tubes are 26mm, and even though the clip-ons were advertised for that size, they kinda bottomed out, even with the spacers included in the kit. I cut up some thicker round tube stock to copy the spacers, much better. Might still need some sort of anti-slip compound, but they're okay for the time being.
Got the petcock, fuel lines, etc., all hooked up, air filter mounted, rear brake cable installed and adjusted, all that last little stuff. It fired up on the second kick!
Here's a shot from the first test run:
No good video from that day, but the stock Pro Sr clutch was slipping at what sounded/felt like 8000rpm. Engine simulations showed a huge dead spot there, and the acceleration matched the sims. The road I was testing gets zero traffic, but it's short, so for a while never got out of the clutch slip while I messed with the needle.
I finally managed to get it above the 25mph or so for the clutch to engage by going around the block a bit, and when it finally climbed out of that dead spot and came onto the pipe, holy cow! It pulls HARD. At least as hard as my 65mph 50cc Peugeot, which has the clutch and variator absolutely dialed for maximum acceleration.
That Pro Sr. clutch setup, though, won't work at all for Colorado Springs. Plenty of 10% or greater grades in the area, plus 20% less oxygen than at sea level (means 20% less power), it simply won't climb them much faster than walking speed, slipping the clutch the whole time.
Two main options to deal with this: engage the clutch at a much lower speed, like 4000rpm. That's somewhere around 13-15mph with my current gearing (16:57 primary with 10:60 sprockets, geared for about 50mph at 15,000rpm). The sims show a dip in the torque at 8k, so at lower engine speed there is more torque, so easier to accelerate up to clutch bite. At that point, I may still struggle to blast up hills, but if I can climb into that dead spot at 8k, I'd at least be doing ~25mph which is the speed limit on most of those start-from-a-stop hills anyway. If I encounter a faster hill on a bigger road, no problem, I'm already on the pipe and can blast up it without issue. Not a terrible option, and can be improved immensely with something like ATAC or a trombone pipe (future projects once the bike is more complete). It's the "reliable" route, and conveniently the clutch springs from the KTM 50 SX Mini Adventure (significantly down-tuned version) swap right into the stock clutch, and should be set up for 4k-5k operation.
The other option is to raise the slip speed - I have a Tomar clutch on hand for this, much better than the stock three-shoe. It's set up for about 9500 out of the box, and has a good amount of easy adjustability (springs can be tensioned without removing the clutch, and options for spring size, too). By 9500, the engine should be making good torque again, making it no trouble to blast up hills (albeit loudly). Butt dyno on that first test ride tells me there's not a hill in the area that can stop me with this setup. But really tough on the clutch.
Here's a crappy flyby video, but you can at least hear it come onto the pipe: