Appreciate the advice. It seems that the head might very well be repairable, but local estimates have come into the $100-$160 dollar range for seats, and recutting to match the valves. Seems somewhat pricy! Given that my valves are also worn to the service limit (2mm, according to the Honda manual), I may very well look for a low hour/mile head to replace this unit. That will probably put me ahead from a monetary perspective, as I will not have to purchase new valves either. PO didn't do such a great job with the maintenance; who knows how frequent the valve adjustment intervals were done. Will keep you all updated on that matter.
In other news... RE: piston.. that's already been taken care of. I had a machine shop measure the bore for me. Stock is 73, and the current bore is at 74mm. There is some minor rust related pitting to be taken care of, and as such, it'll require a minor overbore. Given the sizes available, I found a Wiseco 75.5mm piston kit w/ gaskets for a fairly reasonable price. Rather than jump straight to the 77mm bore, this should allow me to give myself one more bore (77mm) further down the road, before having to worry about changing the sleeve and all of that.
Couple of items arrived in the mail over the past week...
From left to right, we've got... A new pair of fork boots, gasket kit for the piston, 75.5mm piston, rings & hardware, valve spring compressor, valve stem seals, a pretty much brand new brake caliper, a size 128 main jet, and a new cam chain.
I don't think the bike has ever had a fluid change in the forks. I've got another package that should be arriving Monday-ish with a crate stand, fork oil, and some misc hardware and seals. One of the things I wanted to do was a complete brake and fork rebuild. While trying to change the front tire, I began to remove the caliper only to find that the piston inside of it was falling apart! The pads were badly worn and the top of the brake piston was falling off. While trying to remove the pads, I realized that the brake pins themselves were frozen and semi-stripped. Fantastic
Turned into a nightmare of trying to get the front wheel back on with pistons that didn't want to retract!
After that fiasco, I was looking at replacing the caliper. Sadly, XR250L calipers were listed as a different part number than all of the R calipers. Would they fit? Would they not? I had no idea at the time. To further complicate issues, somebody stripped the two screws on the master cylinder, so I was left unable to flush the fluid. Awesome.
Did some detective work and realized that indeed, Honda used the same mounting bracket for the brake caliper. I was able to find a pretty much brand new early/mid 2000s XR250R caliper that bolted right up. The mounting bracket was the same, and the basic architecture of the caliper was identical, but gave me the added bonus of all of the minor changes and improvements that were made over time. To boot, the caliper still had the OEM sintered pads in pretty much brand new condition! $40 was a great price to pay for all of that. Nearly the cost of pads alone, and here I ended up with a better caliper in new condition to boot! FWIW, that caliper seems to be common across MANY bikes... Nearly all of the entire XR lineup, along with some Yamaha WRs and so on. For any of you trying to repair/replace an old caliper on an XR250L or R, definitely look for one of the newer calipers off an XR250/400 - it'll bolt right up.
With that in mind, I'll be doing a fork refresh. Seals are in good condition, but I'll be giving it a fresh change of 10W oil. Brakes will finally be refreshed, too, as I've got replacement hardware for the master cylinder cover. As for the other items... Currently running a 40/125 jetting setup, and I'll be switching to 40/128 for the final product. That should be correct for the bigger exhaust & slight overbore. Cam chain was stretched to the limits before, and that'll be replaced with the chain above. Pro-X / K&L etc both use the same chain. It is a Borg Warner unit, made in Japan.
Lastly.. we had the exhaust issue to deal with.
Stock 'L' setup on the bottom. Top is an XR250R header, from the 86/87ish to 1995 year. It is very possible that an even newer header might bolt up, as well. I'm amazed at how much is the same across these bikes. I snagged a 2008ish CRF250X exhaust, which perfectly fits the older & slightly larger R header. L header will likely go in the trash, and the exhaust will probably go up for sale.
More updates as they come. Extremely busy, but I'll get this thing finished eventually. I haven't been able to actively ride since late June, and it's beginning to bother me