How To Swap TTR125 Carb to VM24 – Video Tip

Having starting or running problems with your TTR125? There’s a good chance that the stock carburetor is your problem. Instead of spending hours trying to fiddle with it, a carb swap can save you a lot of headaches and make your bike start easier and run much cleaner. Here’s a step-by-step video tutorial on how to convert to the Mikuni VM24 carburetor. If you’re unsure about this conversion or have questions on why you should do it, read all the details on swapping out the stock carb HERE.

How To Remove and Replace Wheel Bearings On A Dirt Bike

Wheel bearings inevitably fail over time, and that time is much less if you often ride your dirt bike through water. Water and mud will eventually seep inside if you leave it wet, causing the bearings to rust and end up seizing. An easy way to tell if your dirt bike wheel bearings are shot is by moving the wheels side to side. If the wheel moves at all then the bearings need to be replaced. Some tools you will need to replace wheel bearings include:

  • Wrenches to remove wheel
  • Screwdriver
  • Punch
  • Bearing retainer tool/pliers
  • Hammer
  • Bearing installer/socket

Before taking any parts off your bike, give it a bath so that it’s easier to work on. Keeping your dirt bike clean makes working on it much easier, keeps you cleaner, and you will be able to tell much sooner if there’s a leak or other problem with your bike. Once your bike is spotless, set it on a stand and remove the wheel that you are replacing the wheel bearings on. Now put the wheel on a wheel stand, a wooden box, or even saw horses to make it easier to work on without damaging the rotor or sprocket.

Wheel Bearing Retainer Removing Tool
Wheel Bearing Retainer Removing Tool

Remove the seals by prying them off with a screwdriver so you can get at the bearings. One side will have a retainer clip or nut, such as the one on Honda motocross bikes, which you’ll want to buy the special tool for. They are pretty cheap for a specialty tool, but make sure you get the right size because they changed over the years. You can try tapping it out with a small punch if you’re careful, but I wanted to re-use the retainer, and for under 20 bucks, it’ll pay for itself even if I only use it a couple times. Tools like this will save you time and the hassle, especially if you need it again sometime down the road.

Once you remove the retainer, flip the wheel over to remove that bearing (If you bought a fancy bearing remover tool, just use that, otherwise for the rest of us that are cheap, continue reading these instructions). Before you go to punch it out from the other side, you’ll have to take the punch and push the wheel spacer that is in between the bearings over so you can hit the bearing with the punch. Now just hammer on the punch to knock the bearing out of the wheel. Punch the bearing in a circular rotation so that the bearing comes out straight and doesn’t gouge the bore of the wheel. The wheel spacer will come out once that first wheel bearing is out, so set that aside until you need to re-install it.

Now you can flip it back over and knock out the other bearing(s). Just make sure you punch them out as straight as possible. Before you install the new bearings, I recommend putting them in the freezer. Metal slightly shrinks at cooler temps, so this will help make the installation a little easier. Clean the area and surfaces of the wheel on both sides where the bearings go in and set your wheel back on the stand/wood blocks.

Some people say to heat up the hub where the bearings go to make it easier to install them, although others will say that it weakens the metal. I haven’t seen any issues caused by heating it, but it’s up to you whether you want to use heat or not. I didn’t use any on my recent rear wheel from a CR125, but it took a little more force to press the bearings in.

Take the wheel bearing and set it on the journal where you will press it in. You can start out with a piece of wood or flat piece of metal and hammer it in until its flush. Make sure you know that it is going down straight, otherwise it can damage the surface. Next, you’ll have to use a round piece of metal or a socket that is almost the same size as the bearing. You want to be hitting on the outer race (outside circumference) of the bearing and NOT the inner race. If you press or hammer on the inner race you will destroy the bearing. Keep hitting the bearing down while making sure it’s straight. You will hear or feel when it bottoms out in the bore, and that’s when you stop. Now you can put the clip or retainer ring/nut back on, along with the seal.

Removing Seal and Bearing
Removing The Seal and Bearing

Flip the wheel over to do the other side, but before you put the other bearing(s) in, REMEMBER TO INSTALL THE WHEEL SPACER. This is just the sleeve that you took out that goes in between the bearings, and it can be easy to forget until after you press all of the bearings in, resulting in hair-pulling frustration. Now you just repeat installation on this side, whether you have one or two bearings left. If you’re doing it all by hand, just be patient and get them in straight. It may take some time, but the bearings will go in (assuming you bought the correct part).

Now you can install the other seal to complete the wheel bearing installation. When you go to put the wheel spacers on, put some waterproof grease on them to help protect the seals and bearings. If they are worn with grooves then they should be replaced, otherwise water will find it’s way to the bearings much easier.

That’s it, just put your wheel back on the same way you removed it and remember to properly torque the bolts. If you have any questions, don’t hesitate to post a comment below…

Good luck, and ride safe!

-Tom Stark

Dirt Bike Trail Building Tips – Know The Land

Hare-Scramble Practice Track

After long and hard work of building a loop of riding trails, it’s a blast to get on them right away. Unfortunately, they will quickly get boring…. That is, unless, you incorporate some obstacles in them. These “obstacles” can range from: fallen trees, to large rock sections, all the way to rutted hill-climbs with a combination of logs, rocks, and tree trunks all the way up.

For most of us that don’t have machinery that can move and haul equipment and obstacles as such, we have to get more creative. Depending on how technical you want your trails to be, the goal is to make the trail so that you can incorporate as many obstacles as possible with minimal/no effort in moving them. I try to make it so that if there is a large/difficult obstacle, such as a downed tree, I make a line that goes over it, as well as one that can go around for less-experienced riders (if possible).

Even if you have a trail loop already, you can still go back and scrutinize what you can add to the trail. Who knows, you may find an even better route than what you had before. Go ahead and change it up if that’s the case, even if you didn’t find any obstacles to include.

 

What I try to look for are some nice rounded logs/downed trees, long fly-aways, steep hills/hill-climbs, valleys, and anything else that will mix it up, while still keeping the trail flowing, which is key (more about that in a later article). For logs, I usually make the trail go perpendicular over them (better for beginners), and sometimes stack them up in a pyramid-like shape to make it more challenging.


Off-Camber Switch-Back Section

If there are any hills, I look for a line to make a sweeping corner that turns and goes up the hill. Once I get near or to the top, I make a 180 degree turn to go back down, if possible. It’s hard to tell you what to look for exactly, since every woods is different. You just have to look for lines that connect and flow well, and possibly include obstacles.

Remember to get some Helmet Cam footage of your trails, and if you have any more ideas, feel free to comment. Ride safe, and stay tuned for my future posts on Trail Building!

-Tom Stark