Honda XR280R Build
Riding in Bend and the PNW in general is great for many reasons...scenery, open spaces, terrain that is interesting but not brutal. One of the best reasons though, is some awesome singletrack. However, to properly enjoy it, you need the right bike.
The story of this build started back in 2011 when I was vainly attempting to ride my cumbersome XR650L on a singletrack ride... with a bunch of faster riders... all of them on lighter bikes. This ride was in the winter, so the trails were super greasy, not helping my efforts. It looked like this:
After trying to keep that thing in a narrow little groove for four hours, it was painfully clear I needed a different bike. Something lighter, more agile, but also easier for my aging desk jockey reactions to deal with, and something with a plate so I could connect trails. I created a shortlist with several models, and started looking.
I was looking for the usual models, 250 and 450 4ts, preferably a Honda, but it did not have to be. At some point I heard about a blown up XR250R down in Sacramento with a motivated seller. It was not the first bike on my list, in fact, it was not on my list at all. But, I looked around, and found that a few guys raced them with some success, winning Nationals and medaling in some ISDEs. The fact that it needed some work was not a deterrent, and the fact it had a cheap asking price was like a siren song to me.
The bike did not run, and the seller wanted to cut a deal over the phone. It was fairly new, in great condition, but he thought it burned the top end or something serious. He wanted me to commit sight unseen, so we haggled a bit, and came to a deal. I hopped in the truck, drove down from Bend, and bought it. It was a bit neglected but had very little use:
After getting it home, I powerwashed it and took it to a local shop to diagnose. After just one day, the tech gave me a call to deliver the news. Like many skilled mechanics, he is a man of very few words.
"Your bike is ready."
"What do you mean "ready"?"
"I mean it's running."
"Huh?"
"Yea, running."
"How? Isn't it blown up?"
"Nope. Pilot jet fell out. Put it back in and it fired right up."
I was pretty happy.
I happily rode the heck out of the little XR for two years, and did the usual small mods along the way. Suspension springs, controls, jetting, guards, etc., but nothing serious. I have NEVER met a bike, street or dirt, that I did not want to gear lower, but strangely this bike was worse when I did. The bike was a joy and hauled my fairly large ass, quite well, through woods, desert, and of course, lots of singletrack. 
At a certain point I realized Honda's basic platform, typical of Honda, was excellent but also spec'd very conservatively. The power was mild, the delivery gentle, and the 80s era suspension soft and cheap. The usual way people address this is by buying a different bike. But it also had a fantastic wide ratio 6 speed transmission, absolute simplicity, Honda reliability, and, baby ohhh baby, that low seat height and short wheelbase. Looking at specs I saw a path that took the basic bike, added modern suspension, a little more power, and gave me a different and perhaps better result than any other machine.
The first step isn't immediately obvious, but it is simple and very effective: most all playbikes and dual sports have heavy pistons and low compression. Contrast that with anything modern or racy, which have short, light pistons and high compression. Swapping the piston out with a 280 kit from JE Pistons greatly increases the cylinder pressure, which, on this mild motor, gave a shockingly big increase in grunt with almost zero downside. Like, dude, WTF just happened, and why didn't Honda do this? People generally are hesitant to go into the motor, but it's worth noting this is relevant to many other bikes such as the Honda CRF 300L, Suzuki DRz 400, Suzuki DR650, Kawasaki KLX 300, Honda XR650L, etc.
Something I had done very early is a perfect example of both how mild Honda spec'd this model and how much potential they left ignored. I had read that the welding inside the exhaust headpipe was sloppy and obscured the openings. However when I actually saw how bad this was I was nearly floored. The blockage looked as if it reduced 10% or more of the opening! Remember an engine is basically a big pump, and anything limiting its flow in or out reduces its effectiveness (look up Suzuki JR50 washer removal...). It is fantastically an easy solution though; grind those welds down and you have a free increase in power. Before on the right, after on the left.
The second step was to bring the bike into this century by swapping to a 47mm Showa Twin-Chamber fork from any Honda CR or CRF made after 98. It is not cheap, but once dialed in this is a massive, ginormous, epic upgrade, period. There are people out there who say it isn't that significant, they either 1. didn't do it correctly, 2. are completely ignorant, 3. full of crap, or all of the above. There are also people who have done the swap incorrectly, and will tell you it's a great result. I've ridden some of these bikes, they were awful. To truly understand this swap takes a lot of research and trial and error, which I did to excess. It is not a mechanically difficult swap, in fact that part was kinda easy. The hard part is gathering the information, getting the necessary parts to make the swap, and SHORTENING THE FORK LENGTH TO MATCH THE BIKE. You will need to memorize - not necessarily understand - a few specs surrounding trail and offset to get a good result. Once finished it was a different bike.
During this iteration I also tried an expensive FCR pumper carb only available from Japan, failed, reverted back to the stock Keihin, studied swapping to an XR400 shock or linkage (won't work), tried a bunch of different tires, added Bib Mousse's, recoiled on horror at replacing the Bib Mousse's, and studied every other part of the bike for hidden potential. By far, the piston kit and the suspension were the biggest payoffs, it was not perfect but worlds better than stock. The bikes torque-y motor and short wheelbase made it easy to ride and super fun, particularly in the woods.
Then......on a particularly nice day of terrific PNW riding, this happened:
That, my friends, is a broken shift shaft. This is not minor damage, it requires splitting the cases. Since I was forced into that, I used it as an opportunity to refresh every nut, bolt, bearing, seal, etc. and to make it street legal. A 1996 frame, with a street legal title was secured from EBay (Fight Club rules here please). It was also a chance to make it look pretty too.
The first step was to gut my poor little buddy:
The frame was reinforced in the kickstand area (an XR weak point), reworked for CRF forks, and powdercoated. Because the XR is a dry-sump engine design, holding some of its oil in the frame, it is critical that every. last. molecule. of sandblast grit be cleaned from it.
Every bolt was wire wheeled, every bearing and seal replaced, every wire connector cleaned, new cables, etc. On reassembly, everything was greased, Loctited, and / or torqued. Some parts, like the shocks and forks, would be serviced after the bike was reassembled. To keep organized, I set up the two units side by side:
The rolling chassis would get new front and rear tires, springs, and plastics.
Details:
I had a gouge in the original tank, it did not leak but did concern me. Along the way I found a new white tank from a 96, so I decided to go with a mix of white and red plastics. The look is nice, makes it look more modern. Here, the rolling chassis is ready to go back to the shop for assembly.
Since the cases were apart, I considered having them machined to accept an even larger 300cc kit. However, there was some question whether the revvy 300 kit, which has low compression, is more useful than the torquey 280 kit, which has higher comp. I passed on that, but I desperately wanted black center cases. First attempt was gonna be painting. For prep, I set up some buckets of solvent to soak off 2 years of dirt and cooked Northwest sap: 
One bucket was carb dip, the other Pine Sol. The Pine Sol was not bad, whereas if I never have to use that nasty toxic carb dip again, I will be happy. The before and after:
Got some throwaway screws from Ace, to bolt the cases together. Gave it one more clean, then CAREFULLY taped it up and sprayed:
The final result looks good in the picture, but was not very durable, and would have looked bad after 2 or three rides. When you get this deep into a project, it is unwise to cut corners. I know this, but was a little torn because the good riding season had arrived. Still, I decided to @*^#!! do it over.
After some checking, I found a local place that does a high temp ceramic coating. THIS TIME, it came out much better:
The Ceramic coating was applied by a local company here no longer in business. This material is much better for this application than regular powdercoat, as it is highly heat resistant and super durable. It also has a nice uniform finish that looked terrific.
I am fairly technical, but I leave bottom end reassembly to pros (so I do not have to do it over....). So, I dropped the cases and rolling chassis off back at M-Tech. Here is where another time / money setback popped up.
I had replaced the OE valves with premium Kibblewhite units about 100 hours earlier. The OEs were not worn, but Kibs are supposed to much more durable. Anyway, while I was cleaning the head, I squirted some contact cleaner into the intake passage. It quickly - too quickly - seeped out of one of the intake valves. I mentioned this to Matt at M-Tech, he being the detail guy he is, checked the valves....bad news. For some reason, my pricey Kibblewhite valves were mushroomed, and needed to be replaced. THIS TIME, I went for OEs again.
In addition, I replaced the clutch steel plates, friction plates, and springs. All bottom end bearings - ALL OF THEM - were replaced. Transmission gears were inspected, and all good. As one last detail, I got a steel braided brake line and a set of OE CRF-X pads to make them stronger. Then, I brought this truck bed full of bike and parts to Matt. He reassembled the motor, revalved the forks, put everything together, and gave me back this little gem:
One of the best feelings we moto people can have is a new bike. I say that building, tweaking, massaging, and most of all, learning about, every part of the machine may be even better. I liked the bike before....but now I was absolutely giddy over this newest iteration. Best of all, I became familiar with every part of the machine. Here are a few detail pics:
Steering damper:
New spring, frame guards, etc.
CeraKoated cases.
Exhaust is CeraKoated, and kickstart lever was rebuilt.
Polisport headlight, CRF forks and fender, and Acerbis Rally 3 guards. Note that guards use triple clamp mounts.
Before:
After:
The bike has only been out on easy break-in rides, but initial impressions are great. 
The bike still did not have a lot of power, but it was surprisingly grunty and the 6 speed was awesome. The short wheelbase and easy power continue to make the bike a lot of fun and little work in the woods. There was still one last weak link to work out, the stock carb. It's small bore and primitive choke plate really limits top end. Worse, it foods when the bike falls over. Swapping to a larger flat slide carb with an open bore would add power and make the power spread longer. This would have been another level of performance and rideability, but I never made it there.
A lot of people point out, often with some condescension, that I could have just bought something finished. I recognize this, it is obvious. However, I like to take stuff apart, examine it, understand it, and put it back together. At various points along the process, I too, wondered what I was thinking. But this one was a lot of fun, and I am glad I did it.
Thanks for reading.
BP
- Brian Price