I haven't been very present on the forums lately, mostly distracted with old dual sports though of course I'm still riding my K1. My K5 developed a noise before the holidays, I'm thinking it's time for primary chains and tensioner and a full inspection and freshening up. Unfortunately I haven't got around to it as I've been busy with dual sports this winter.
So the XL600 got new rejetted. Appreciably richer on primary and secondary carbs helped, leaner on the slow jet to ease starting as it was way big from the previous owner. I still need to fine tune jetting as when letting off from WOT a bit there is a stumble and surge. I think jetting is pretty close, but need to raise needles so I'll do that next time it's convenient.
I focused on suspension work recently. I swapped the 37mm XL600 forks for a set of 43mm '97 XR650L forks which are longer and of cartridge design. More travel is more good. I rebuild those with springs appropriate for my weight, new seals, and synthetic 5w fork oil. To mount the original XL600 gauges to the top triple I had a local welding shop weld new tabs on the top triple. Some longer hoses, cables, misc. brackets, and so forth and the front bolts right on. It's a big improvement and looks clean and like it could have come from the factory that way.
For the rear I swapped an '87 XR600 aluminum swingarm. it is longer and a bit lighter than the steel XL600 swingarm. The XR600 and newer XR650L dual sport do not have cush drive hubs though for less wear and smooth operation on pavement. As the aluminum XR600 swingarm is narrower, to retain the XL600 cush drive hub I machined about 3/8" off the brake plate outer "nose", ground down the brake stay pin to fit, and clearanced the groove on the brake plate for the brake stay pin on the swingarm. I also had a shorter spacer made for the left side of the rear wheel. On the XR600 swingarm, just about all of the shorter width is removed from the left (drive) side, so the wheel ended up not centered to the frame. I had to lace the wheel offset to make up the rest of the difference and get the wheel centered. All said and done, it fits and all is well. For now I put the old XL600 shock back in, but it's very inadequate compared to the new modern front suspension, though the swingarm gives a bit more height from the extra length. I have an XR600 shock I will rebuild and install though. I also replaced a damaged clutch cover and upgraded the oil pump to an improved version for a 2020 XR650L along with new drive and driven gears, which are one tooth more on drive and one tooth less on driven for more oil pump RPM and oil volume.
All said I'm really digging the old XL and getting back into riding off road. I also picked up a matching '86 XL350 for the boss back in November. We did all the basics and it runs great, but it's too heavy for her to pick up on her own when she drops it and while she can start it normally, she cannot start it after it has flooded from dropping it. This means we need a lighter dual sport for her. In my Craigslist perusing I stumbled across a street legal 1977 Yamaha IT400 (two stroke) which was converted several years ago in CA. I used to have an '82 IT465 and regret selling the bike, but it's impossible to get them street legal here. I jumped on the IT400 since it had a street legal title, did the usual stuff plus a top end, and had a little fun with it but despite being lighter than the XL350, at 40 HP and the twitchy nature of a two stroke it's not suitable for the boss. I'm keeping my eyes open for an '85 XL250, for fun to add to the stable since apparently I'm now collecting 1985 model year XL Honda's. The 250cc-600cc RFVC bikes are all basically a 600. Minimal chassis and suspension changes and same engine but smaller bore or stroke so they're all heavy. The boss asserts that we're a Honda family, so we've been looking for an XL200 for her, a 3 year production bike which is older tech engine and lower output but significantly lighter and still modern monoshock suspension that can take all the upgrades I did to my XL600. Finding one with a title is a struggle!