Update minus pictures, the camera's still in the garage all set up. I'll get pictures later once I have time to resize them and
The left side pivot bolt takes a 14mm allen bit. The right side is a 10mm allen, and a 23/24mm or 1" deep socket can be cut down to make the tool for the locking nut. I cut down a gearwrench 23mm deep 3/8" drive socket, using a 1.25" speedbor bit and some scrap wood to make a template to align the keys. They're ~10mm wide and located at an easy 90* from each other: four lines on a square of wood, drill down the middle, cut off the 6-point section of the bit to get to the meatier part of the socket, mark and cut. Freehanded it well enough with an angle grinder and a cutoff wheel. When I got the two swingarms out and side by side, there was an immediate issue: the Sabre swingarm is ~1.5" wider at the pivot than the CB650 swingarm. HOWEVER, the Nighthawk arm does not butt against the frame on both sides; actual clearance difference is closer to 1/4" rather than the 1"+ the width difference suggests, especially once the step is accounted for on the Nighthawk arm. The bearing diameters are different, that was obvious; the Nighthawk uses NSK 30202 bearings (15x35x11.75mm bore diameter X outer diameter X depth) while the Sabre uses 30203J bearings (17x40x12mm). There is also not enough thickness to the Sabre arm tube to machine the step on the shaft side, though there is PLENTY of depth on the brake side to cut down for clearance. Given my original intention to leave the Nighthawk frame intact, only adding tabs and not cutting any part of the frame, I have a plan. I'm going to have the Sabre swingarm cut to make clearance, then I will fit a steel sleeve bushing into each side, sized to allow me to continue using Nighthawk bearings, seals and grease retainers. Since I am not increasing the weight of the bike in any significant way, these will be fine. These sleeves will allow me to machine the step on the driveshaft side, and give me some additional thickness on the brake side. A stock Nighthawk right side pivot bolt can easily be cut down and machined to accept the closer frame, and should actually be stronger for it with less lever arm. Sleeving to use the Nighthawk bearings allows me to use stock, readily available bearings and seals. Using the bearing codes means they're ~$16/each versus $45+ at a motorcycle site or dealer, and this isn't "direct from China" pricing either; that's $3 each. Not worth it to me, I'd rather have "Made In Japan," "Made In Germany," or "Made In USA" on my bearings. My ONLY concern with this is the difference in tube centerlines for the driveshaft tubes. The Nighthawk arm has a tube centerline, measured from the flat outer face of the bearing tube, of 1.7". The Sabre swingarm, measured similarly, is 2.4", for a difference of .7". I obtained these centerlines by clamping a straight edge to the bearing face on the outside of the swingarm, then measuring to a straight edge held against each wall of the driveshaft tube. There may be an issue with my methodology. 1.7" does not appear to put the driveshaft universal joint in any danger of scraping or rubbing on the outside of the Sabre swingarm tube, though that .7" difference does mean that the joint will be operating at a bit of an angle. Are there shims I can remove to move the angle drive closer to the transmission before we enter the swingarm? I am also going to try getting a little bit of material taken from the Sabre arm to reduce that distance, but I can't take more than a 1/4" that way, IF that. Will still leave me nearly 1/2" out of alignment, but only on the driveshaft tube centerlines, not necessarily the the driveshaft itself. Looking at the way the driveshaft sits in the Nighthawk tube with the final drive case installed, it rides really close to the edge of the tube anyway rather than down the centerline. The Sabre has an extra .4" of clearance on that side (1" even from outer face to inner tube wall vs. Nighthawk's 1.4"). I think I'll be fine. On a non-swingarm (or perhaps tangentially related) I will be building a bracket to move the rear brake pedal assembly 1/2" further from the frame. This will let me mount the rear master cylinder where it won't interfere with the swingarm's movement, and looking at where the footpad ends up it won't be a problem for my big foot. Any thoughts, ideas, questions so far? -Kurt -- You received this message because you are subscribed to the Google Groups "Nighthawk Motorcycle Lovers!" group. To post to this group, send email to nighthawk_lovers@googlegroups.com. To unsubscribe from this group, send email to nighthawk_lovers+unsubscr...@googlegroups.com. For more options, visit this group at http://groups.google.com/group/nighthawk_lovers?hl=en.
