I have a ’94 XCR 600 that is pretty much stock except for the ports have been polished and it has a 133.5″ track on it. The problem is that I can run the tach past 10,000 rpm at will on hardpack, at almost any speed. So I installed a set of #10 weights from an Ultra and now the rpms dropped to a steady 8500 (which I figure is where I’m supposed to be) but my bottom end and top end is weak, and the clutches are not shifting all the way out. I ride at an elevation of about 2,000 feet, the gearing is 20/39, I’ve got a white/blue drive clutch spring, yellow Erlandson secondary spring, stock 36 degree helix, and I ride on both trails and fields. How can I get my power back and keep the rpms down?
The yellow Erlandson secondary spring is a good product, but you’ll need at least 54 gram weights to make it work right and keep the rpms down. The problem is that your engine doesn’t have enough power to pull this combination. I’m not sure as to what the white/blue spring rate is in the drive clutch, so I would try a Polaris almond/yellow that is a longer version of their blue spring. This will bring the engagement up but still allow you to shift out at the right (8500-8700) rpm. Since the ports are polished you can spin it this high. The #10 weights are only 51.5 grams, go up to the #10 ALs that are 53 grams. I would change your gearing to 21/39 (at least, maybe more). Install a silver Polaris secondary spring (in hole #2), a Polaris T1 helix (old Storm helix) and hang on. Your engagement should be 4500-4900, shift out should be 8500-8700, and it should pull harder than any other “stock” XCR you’ve ever ridden.