After almost a month of retirement, I was finally able to get back to my project bikes after about a four-month hiatus. I decided to get Bultakenstein’s new Shinko tires mounted. The matte gold paint didn’t come out as well as I’d hoped, but the lip of the rims are painted, so I can just mask off the tires if I want to do any touch-ups later on.
So, back to my favorite task: mounting tires. With inner tubes, for an extra fun time. Fortunately, Santa brought me a set of NEIKO tire spoons. Those, along with the Beadbuster lube, made things a lot easier.
But I punctured the tube! That’s something I have not done in a long time. Ok, just do it again—and again, a second puncture! That’s when I realized that the Motion Pro “RimShield II” rim guards I was using to protect my gold paint have very pointy corners on the inside edge. Yep—sliding them around inside the rim was catching the tube. I ordered a third tube, and this time I raw-dogged the spoons directly on the rim. Yes, I did get a couple of scratched up spots, but I now had two wheels that held air.
Time to get the chassis back on its wheels. One of the minor little things I needed to do was to split the axle bushings that go in the front forks. Otherwise, cinching up the fork caps would just grip the bushings without actually taking up the free play between the axle and the bushings.
At the other end of the bike, the location of the shock mounts on the SRX-6 swingarm required extending the length of the rear shocks. In this photo, you can see the original lower end eye compared to the short and long extended eyes available.
I first tried the longer extensions, and they were clearly too long. The bike sat so high I couldn’t flat-foot it unless I sat way up at the narrower front edge of the seat.
So, I swapped them for the “in-between” size. I am happy with how the bike sits now, but I did some calculating, and assuming the rubber bump stops can compress by 70% (a general rule-of-thumb I’ve seen online a few places), the wheel might be able to gently kiss the rear frame frame when bottoming out. The rear spring rates are pretty high, so it’s unlikely enough that I’m not going to worry about it. (Well, I’m actually going to mildly worry while doing nothing to fix it.)
So, here’s the updated chassis with the SRX-6 swingarm (and larger pivot bolt), slightly extended shocks, 18″ rear rim, and gold paint.
Next up are new rear engine mounts. Let’s get the engine back into the frame. Open the crate it has been sitting in, one quick hoist, and—something is wrong.
Hmmm. Why won’t the bolt holes line up?
It’s the new swingarm! The heftier pivot tube is just that much thicker, and now interferes with the crankcase at the rear.
WELL, $#!%.
Just out of curiosity, I pulled out an old set Model 68 Pursang cases, which I modified to fit this frame. Between 1970 and 1977, Bultaco moved the swingarm closer to the output sprocket, and of course altered the rear mounting bosses to accommodate. I accomplished the same thing with a hole saw and a file.
Hmm…
I could trim away some of the crankcase.
I could modify the swingarm for clearance.
OR…?