Dirt Bikes Part 1
A Suddenly Fun Sunday
Anyone remember that movie where the message is to take something you desire or want to experience and “put it out there for the universe”, and how in some way or another it will come to you or be available? Well I’ve long been thinking about how cool it would be to ride dirt bikes on some of the local mountain trails and forest service roads near me, and just the other day after passively mentioning an interest in trying to figure out how to rent one, my friend whom I’m calling Red on here tells me he’s got three just sitting around going unused that we can try to repair and ride! Turns out he used to ride a ton when he was younger and they’ve just been sitting unused for over a decade just waiting to be restored.
My Sunday just got a whole lot more exciting!
Barn Find
I guess a “shed find” is probably more apt!
There was the first bike we’d be looking at, a Honda CRF100F from 2004! Definitely dusty, dirty, and in need of some love, but it still seemed pretty solid and was simple enough that Red and I (two guys who’d never done any kind of engine repair before) felt confident that we ought to be able to get it running again! We had after all watched several videos and read several forum posts about restoring bikes, so we were obviously experts now!
Day 1 with the Red Baron
We wheeled it out, leaving the two other bikes which we could then tell would need even more work than this one, and got to work by first giving it a well-needed cleanup.
I joked about us being experts thanks to a few videos and forum threads, but they had given us a good direction to go on since neither of us had done anything like this before. Heck, I haven’t even changed my own oil before, not for lack of interest, but lack of confidence in working on an engine, so I was excited to learn!
Some of the thing we’d apparently want to do would be to drain all of the stagnant fluids that had sat in the thing for over a decade, clean anything as best we could so that there was no dirt, silt, or obstructing matter in the way of operation, replace any of the parts that made up the main combustion process if they were in need of replacement, and fill ‘er up with fresh fluids, so first thing was first, it was time to remove and drain the gas!
We got the tank freed, relocated a spider that had decided to take up residence on the underside, and drained some fuel that looked suspiciously like water. Using a little bit of fresh gas we gave it a good shake and rinse before disposing of that too (and the sediment that came along with it), and set it aside to dry off while we worked on cleaning up the fuel valve, filter, and petcock as best we could.
Since we didn’t have a bike shop nearby that sold these kinds of parts and only a NAPA down the road, we’d have to make do with cleaning stuff like this to the best of our ability until a replacement could be delivered. Using a little more gas I washed even more sediment out of the screen filter, and we got the fuel valve switch turning again.
Red set about draining the engine oil while I removed the carburetor to give it a once-over. According to his brother, the OEM carburetors on these things were pretty bombproof so as long as nothing was actually broken, we ought to be able to get by cleaning it and replacing any of the moving parts that were in need. We made note of the model and would later order a replacement filter so that we could be sure it would do its job right. I drained it of fluids, scrubbed it as clean as I could, and also made note of the gasket shape so that we could get a new one since this one was falling apart.
Then there was the engine air filter, and oh boy was that thing in bad shape! Darn near fell apart when we touched it, but I guess that’s what you get when a spongy foam material coated in oil sits undisturbed for that long! This was another thing we knew we wouldn’t be able to fully replace the same day, so we removed the old sludge that was formerly foam, washed and dried the filter completely with an air compressor, and since the only testing we’d be doing would be on a short paved road for today, put the metal mesh filter back in. We wouldn’t be taking it off-road without a proper filter in place.
Finally we dropped in a new spark plug, having picked up a 1:1 replacement at NAPA, put everything back together, put a little gas in the tank, and got to kicking. It took a good minute or so of trying but eventually we could hear the engine catch something. A few more tries and the engine roared to life and sustained itself! Victory! Red was excited to hear his bike run again after so long, and I was thrilled that we’d managed to actually take it apart to a pretty fair degree, put it back together, and get it working!
We finished tightening everything back down (mostly the seat at this point), and Red took it for his very first test drive, it being his bike after all. I got to recording, and he set off down the driveway. Here I was thinking he’d just be riding it down and back up his first hill though, so imagine my surprise and light concern when he wasn’t back in five minutes and I couldn’t find him anywhere after heading down the driveway myself. I started checking the bushes, hoping that we’d remembered to properly tighten everything and he didn’t go sailing off into a ravine when he called me.
“Hey, I ran out of gas…”
Turns out he’d gone two miles down the road in the excitement of having it working again, and it died right as he reached the farthest point before the main road. Oops! We had, after all, only put a tiny bit of gas in the tank at first. I loaded up the can in my car and went to rescue him, and after we got it back to the garage, it was my turn to give it a try.
Now I’d ridden an old Honda 4Trax ATV on my grandparents ranch many many times growing up, and had become familiar with clutch-less shifting, so I guess I must have gotten it in my head that this was clutch-less too. I’ve never ridden a dirt bike before at all, only years of riding a bicycle, so when it came time for me to start it up, it had been left in gear, and I wasn’t holding the clutch down since I’d wrongly assumed it was a brake… Yeah…
After picking myself and the bike up I got it in neutral, acquainted myself with the clutch, and went for a real test ride. I only planned to go down the driveway and back, but just like when Red went on his test ride, the thrill of the thing finally working was overwhelming and I too went the full two miles down the road. What a blast!
I’m afraid I don’t have any footage of me riding at speed, I don’t have any sort of action camera or phone camera mount (thought I might 3D print one of those now that I have a working 3D printer!) What I can say is this though: that thing is addicting! We took turns riding it up and down the road a bit, then troubleshot a small fuel leak we were seeing from the carburetor. Looks like there were indeed some parts we’d want to replace there. Considering it was running, though, especially after a decade of wasting away, we were both pretty satisfied!
That night Red got some parts ordered, and we made a plan to meet back up next weekend to properly fix up the engine air filter, install a new fuel filter and valve, and replace some parts on the carburetor.
Day 2 with the Red Baron
Lucky us, the parts arrived sooner than expected, so that next Saturday we met back up and got back to work! Inside the carb we replaced the pilot and idle valves, needle valve, and the main O-ring up top. I also took the manifold off, scraped off all of the disgusting old gasket, gave the surface a proper cleanup, and got it put back on good as new!
We also prepared and installed the foam engine air filter so that we could take it into some light off-roading thing time around, and filled the tank up a bit more so we wouldn’t have a repeat of last time’s rescue mission.
By this point, having replaced carb parts, the spark plug, the oil and gas, many valves and seals, and the fuel filter, the engine was in a pretty good spot and was seeming to run quite well! One of the only things preventing us from declaring it done were the tires: they seemed to lose air after a bit of riding, so they wouldn’t last on any kind of long drives. A short test in the pasture should be fine though, so we layered up and gave it a spin!
Once again, I can see how these things can be addicting! What a rush going up and down hills and through brush! I hadn’t had this much fun on a vehicle in a remarkably long time, and it was made all the more satisfying because we’d gotten it to this state with our own two hands!
We’re looking into some replacement tires now so that we can actually put this thing through its paces, and began taking a look at the next bike in the list, the white one! This one would need considerably more work, but should also be considerably more powerful!