No, this isn’t like one of those forum threads you see posted by some 12 year-old wondering how to make their xr100 fast enough for motocross racing. This is taking one of, if not the best, all-around and most reliable engines for adults and kids-alike, and placing it into a much more race-suited and agile chassis.
I’ve seen many of these builds from people in their small garages or workshops, and wanted one so bad that I just decided to do my own build to see what I could come up with. This is my first XR100 conversion bike, so it may not look factory in the beginning. I am doing this to show that with some basic and relatively inexpensive shop tools, someone can do this in their own garage on a budget, as it will be one of the funnest pit bikes to ride for us adults.
To get this project started, I happened to come across a rolling ’97 Suzuki RM80 that someone had started doing the conversion on. Luckily they didn’t go too far, so it was the perfect candidate since I picked it up for pennies. Most of these conversions are done with a Honda CR80/85R chassis, but I happened to find this Suzuki first. If I like it enough, I plan on building more of these conversion bikes. And that is when I will fix any issues I come across with this first build and take the time to make things look a little nicer. In addition, I’d like to try different bike combinations, such as a CR85 or YZ85 for the chassis, and possibly a TTR125 or DRZ/KLX125 for the transplant engine.
Here is how I got the roller…. I know, not much to look at, but when it’s finished, it will be more than worth the work. As you can see, the cradle has already been cut, and the previous owner started the build but gave up. Fortunately, I got a junk XR100 engine that I can use to mock up all the mounts (very useful because I didn’t have an XR100 yet).
Since this is such large project with so much information and lots of pictures (I know how everyone likes pics), I’m going to separate this into a few different parts. Next part will be tear down and engine mock-up, so stay tuned if you want to see how one of these is built in a garage…
If you are going to race motocross, let alone ride dirt bikes, you better have the proper protective gear. One of the first articles of protection for your body should be boots. These come right after a helmet for importance because you need your feet and legs almost every minute of every day. I don’t know about you, but that seems like a lot of time!
I have been wearing a pair of Alpinestars Tech 3 motocross boots and they have been a great addition to my protective gear collection. There are several specifications that you should look for in a pair of motocross boots. These are: break-in time, type of material they’re made of, buckle/restraint system, comfort, sole, how much grip they have, and other little things.
The break-in time is how long it takes for your boots to go from showroom rock solid to them being just flexible enough for your feet. Finding the pair of boots that break-in the quickest is not necessarily what you should look for. In fact, the faster they break-in the quicker they might wear out. Wearing brand new boots while racing is probably the worst thing you can do for protection. They will restrict your feet and be very uncomfortable. So it’s crucial that you break them in before going for a long ride or a race. Even though some motocross boots don’t require break-in now there are still many lower costing boots that do. The Alpinestars Tech 3 motocross boots do require a break-in period. It took mine about 3-4 hours of riding for them to be completely broken in. They were pretty stiff at first, like all boots, but they were just flexible enough after using them for a few rides.
These boots are definitely on the higher end of material quality, even though they are about the price of an entry-level pair of motocross boots. Alpinestars Tech 3 boots are made of high quality leather and abrasion-resistant polyurethane. I will personally say that these boots last a long time if you take care of them. I’ve had mine for almost two seasons and they still look like new. They are high quality motocross boots and will last longer than most.
Although buckle issues may seem pointless at first, I hear of many riders having problems with the buckles on their motocross boots breaking or not staying on tight. The Alpinestars Tech 3 boots have a good and simple buckle system. There are four latches that are strong and easy to buckle and unbuckle. They have never come off while riding with them on. I have not had any problems with mine and don’t see having a problem with them in the near future.
If you buy a pair of boots that aren’t comfortable then you are going to regret it, and forking out $200 on a pair of motocross boots that are worthless is something that riders do not want to do these days. So it’s best to know what you’re getting before you buy it. A simple way to see if you like the fit and comfort of motocross boots is to try them on at a store, although this is not always accurate because the fit differs once the boots are broken-in. My Tech 4 boots felt pretty good when I first bought them. There weren’t any sharp edges or anything scraping against my legs. As soon as I broke them in they felt great for how stiff and strong they are. The Tech 4 motocross boots gave me plenty of support while still being snug and pretty comfortable to my feet. These boots aren’t like putting on slippers, but they get the job done, and get it done in a good manner.
The sole of motocross boots can be very important for some racers. It’s because they grip the pegs, and if you can’t stay on the pegs then you are not going to stay on the bike. Aggressive soles will give you maximum friction with the pegs, allowing your feet to stay on them without slipping. The downfall is that they will wear out really quickly. The Alpinestar Tech 3 boots are about in the middle of having mild and aggressive soles. They are good grip and still last somewhat longer then other motocross boots. Mine are starting to get worn, but I’ve had them for about two seasons of riding. The calf plate/heat guard also gave me some grip against the frame of the bike. It is high quality and still in great shape.
The Alpinestars Tech 3 motocross boots are a perfect entry level, or even intermediate, pair of boots that last longer than most other motocross boots. They are also cheap enough for those wanting high-quality and comfort. Remember that your feet are very important, so make sure you protect them with a good pair of motocross boots.
Are you sick of not being able to clear the jumps at your local tracks? Do other riders not like you because you’re always in their way? A simple way to fix this is to build your own jumps in your yard. Although building a jump might not be easy without good equipment, it will be worth it once you make a jump or two because you will learn how to clear these obstacles in no time.
The first thing you want to do is find an area where to put the jump. You probably don’t want to build it next to trees or big pits until you are more experienced. The ground does not have to be flat though. In fact, a little slant or elevation change will make it a easier to build a jump because you can dig into ground for the take-off. Once you found a good spot for your dirt bike jump you should have some other thoughts in mind, such as: what type of jump you want, how big the jump will be, and what kind of dirt you will use.
If you want a motocross style jump that gives you more distance, a good estimation to go by is the 3-to-1 ratio. It basically means that if you have a jump 3 feet long then the height of the jump should be 1 foot. So if your jump is 9 feet long then a good height will be about 3 feet. So far you should have figured out where you are going to put a dirt bike jump and how big it is going to be.
On the other hand, if you want a supercross style jump it will be a little bit different. Motocross jumps are more gradual, while supercross jumps generally have a greater angle and give you more height. The main difference in building a supercross jump is that you want a steeper angle, so instead of a 3:1 ratio it might be 2 1/2: or even 2:1.
A couple more things to think about while building the actual jumps is to make sure it’s gradual take-off and not abrupt, or else you will be getting bucked around and have a high chance of flipping the bike in the air. Also, you want to make sure the take-off/base of the jump is longer than the length of the dirt bikes wheelbase. If the take-off is not long enough then it’s not going to be a smooth jump.
Once you figure out what kind of jump you want and how big it’s going to be then you have to decide what to do about dirt. A well made jump should have a good amount of clay in it, so if you’re lucky enough to have clay or a mixture of clay for soil then use it. If you have sand but don’t want to rebuild the jump every time you use it then you can always bring in some clay. Clay itself is fairly cheap, but if you have to get it hauled in by someone else then it’s going to take a chunk out of your wallet. This is not to say that you shouldn’t make sand jumps for dirt biking, because it’s a easy and will last longer if you pack it down and water it often.
Now to the actual building of the dirt bike jump… If you have heavy duty equipment, such as a skid-loader, then great! But for those that are using a tractor, four-wheeler with attachments, or even just shovels, don’t lose your confidence. It’s still possible to make a good jump, it will just take more effort. Plus, you will build some muscle if you do the work yourself! To cut the building time down to almost half, at the start you can put logs, bricks, or any objects to make the base, then just pile dirt on top. If you’re making a jump on a hill or if the ground is slanted (having the jump go uphill is easiest) simply dig dirt out below the jump and pile it up on the base of the jump. Remember to keep it smooth and fill in any holes or drops, even if they are small. The wider the jump is the better, especially when it’s packed down. For one, it’s wider so you can have more than one line, and it will last longer. If you’re bringing in enough dirt then there’s no need to dig prior to the jump, unless you want more air.
Haul your Dirt Bike on a Motorcycle Carrier to your friends house if that’s where the jumps are.
Just keep putting more and more dirt on the jump until you think there’s plenty, then add a little more. It may seem like a lot, but it’s better than fixing it or repeatedly adding more dirt. As soon as you’re done building the jump you scan it over a couple more times and get rid of any bumps or divots that might affect riding. Another key to having a good jump is making a good lip. The lip of the jump is the edge where the bike takes off. If this is not made right then you will not stay as stable in the air. To make a good lip just smooth of the top and make sure it flows with the rest of the jump. You can look at from the side to see if the angle is gradual or not.
To put the finishing touches you should water the jump and let it sit for a day or two so it hardens…. I think that pretty much covers the basics of how to make dirt bike jumps. Just be sure to build the jumps safe, and that you are making them on your own property. Good luck, and have fun!
It was more like a hallway, but the work area was still smaller than I wanted. I picked up a 2003 Yamaha YZ125 that had some major frame damage. The bike ran well but was not ride-able. The two options were to scrap the main and sub-frame, or take the time to bend and weld them back to their somewhat original form. Either way I would have to strip the entire bike down to the very last bolt and tie-strap. Just by looking at it I could tell this was going to be a difficult, yet exciting project.
I got to work tearing down everything on the YZ125, starting with taking the engine out of the frame. There were a lot of nuts and bolts from the plastics, engine, radiators, frame, and other miscellaneous parts that I had to organize into little zip-lock bags so I wouldn’t lose track of where they went when I put them back on the bike. In the middle of this process I got the sub-frame bent back and welded so that it would fit like normal. Being me, I decided to go the more challenging route of getting the main frame welded instead of paying a couple hundred for another one. Once I took everything off of the main frame my dad helped me by welding it.
I wanted to make this bike look good when it was finished, so I sanded and cleaned off the main frame to get it ready for painting. It took a while, but I managed to find some paint that was close to stock color shade. I then painted it with a few coats to make sure that it wouldn’t peel or chip right away.
The rebuilding process began just after the paint on the frame dried. This is the part where I had to move everything inside…. I started with the foot-pegs, front-end, rear shock, and swing-arm. Those went on pretty easily, so I then took the whole engine and bolted it up to the frame. The rear-wheel and handlebars with controls were next to go on. After that it was just the electronics, carburetor, plastics/tanks, seat, and a few miscellaneous things, such as the exhaust system.
After working inside for some time, this project was well worth the outcome. In the end I think the bike looks good, and I learned quite a bit more about rebuilding these modern dirt bikes (Check out my other article, “How I Built A YZ250F With A Box of Scraps” if you liked this one). Let me know what you think, and if you want to see more projects like this just give me a shout. Thanks!
I love two-stroke motocross bikes, there’s no doubt about it. And if there’s one thing I don’t want to see, it would be the discontinuation of two-stroke dirt bikes. They are just so much fun to ride, and cheaper/easy on maintenance I might add. So, I try to keep up on the latest news about the industry. Fortunately, Two Stroke Motocross.com is there to fill me in on everything I need to know, and more!
I have a million things to do around here, so reading every little article on the net about this topic is just not feasible. Two Stroke Motocross gathers the best, and most important things to know about the two-stroke industry, so I only have read one article to get the latest and greatest information. They post updates about two-stroke dirt bikes, motocross teams, tips and how-tos, and many other articles to fill your 2-cycle hearts’ desire.
I really liked their post, “Two Strokes and Attitude” because it not only gets you to want to persuade people to start riding two-strokes again, but it shows you the best ways to go about it in the motocross community.
If you are a die-hard two-stroke motocross fan like me, you’d better check out TwoStrokeMotocross.com Here now! You won’t regret it; they even have their own TSM Racing Team!! And remember that the best way to bring the two-strokes back is to go out and buy one!
Good luck, and have fun riding! (only possible on a two-stroke….. haha, just kidding!)