Why Does My 4-Stroke Motocross Bike Get So Hot?

There are many reasons why your four-stroke motocross bike is getting so hot. Fortunately, I can show you how to help prevent your dirt bike from overheating.

Before you do anything, there is one thing you should check  that some riders choose to ignore. Coolant flows through the engine to keep your bike ‘cool’. If there’s little to no fluid, it’s just going to overheat. So, before every ride,  pop the cap off the radiator to check and make sure it’s full of coolant. Just by doing this you can prevent a costly engine repair. On the other hand, if you keep having to fill the radiator because the coolant level is down after every ride, then you have problems. There is a leak somewhere, and you’ll have to take stuff apart to find it. It will often be a blown gasket (base, head, or water pump), a hole in the radiator, or in a hose.

2-Stroke Piston That Overheated (Applies to 4-strokes as well)

That brings us to the next possible culprit. A worn or torn gasket will allow coolant to seep through, reducing cooling, and very possibly causing damage. The least damaging can be the water pump seal/gasket. If you’re lucky, it will just dribble out somewhere around the impeller cover and onto the ground. It can also mix with the tranny oil, causing it to corrode and eventually seize. If that is the problem, it’s best to replace it right away.

A blown head gasket can be a cheap fix, but it could also cause an engine malfunction. If you’re running your bike with a bad head gasket, it’s probably burning coolant, which will show up as white smoke out the exhaust.

A faulty base gasket is usually going to be worse. Coolant will leak into the transmission, contaminating the oil. This will eventually cause it to fail, or the piston/cylinder will overheat and seize due to the lack of coolant in the radiators. It can also happen in a matter of hours or even minutes. This is why it’s always a good idea to take the top-end of an engine off (if it’s a used bike you bought) to see if anything needs replacing, or if something was put in wrong by the previous owner (happens WAY too often, so don’t ever think it won’t happen to you!).

The other common factor of overheating is not one that everyone realizes. Water isn’t the only thing that keeps a bike cooled. Air is still needed to flow past the radiators to keep the radiator temps down. So, if there’s no air-flow, then there is little cooling. Simply put, if you’re idling or putting around a lot, your bike is going to start overheating. Not only does it get hot from little air-flow, but the little amount of gas going through the engine also causes it to get too hot. The gas actually cools the intake and exhaust valves as it passes by, so 4-stroke motocross bikes need to be ridden fairly hard to stay cool. This is one of the major reasons why valves burn up, so don’t let your bike sit and idle for very long (How To Properly Warm-up Your Dirt Bike).

There are a few ways to fix these problems. If it’s a gasket, then pretty much the only thing to do is replace it. Improper jetting will cause problems as well. Too rich and it won’t run right at all. Too lean and it will burn the piston down. Read the Jetting 101 Guide Here and it will show you how to properly jet your dirt bike.

If coolant is weeping out of the overflow tube on a hot day, a simple fix to keep the temp down could be a High-Performance Radiator Coolant. It can bring down the running temperatures by up to 50 degrees Fahrenheit. If there is nothing defective on your bike, this alone can prevent overheating problems.

Damaged Cylinder From Detonation

Another way to cool a bike down is with different gas. I wouldn’t necessarily recommend this for that sole purpose, because if your bike regularly overheats then it has bigger problems. Higher octane gas, such as race-gas, will make your bike run a little cooler. Although, doing this will require re-jetting. Higher octane gas burns at a slower rate, reducing the engine temperature. But, if you keep the previous jetting, it will be on the rich side because it’s putting more gas into the engine than it can burn. Race-gas is used by many racers to help make their bike run better (instead of nasty pump-gas), and probably cooler.

-Tom Stark

What’s New On The GoPro HD Hero2 Helmet Cam?


GoPro has unleashed their latest and greatest product, the HD Hero2 Helmet Camera, claiming to be twice as good in every way! Since helmet cams have become so popular in the motocross realm, I had to check it out myself. I didn’t think GoPro could make what they already had much better without the camera costing a fortune, but it looks like they had a few more tricks up their sleeve…

The All New GoPro HD Hero2

 Image Quality

If you thought the previous GoPro HD Hero had good image quality, you gotta check out the Hero 2. Not only is the image sharper, but the low light image quality is greatly enhanced. When watching footage from this helmet camera, it could be mistaken for a professional camera. Night-time videos were sub-par on any other helmet cam, but GoPro figured out how to capture those night-time adventures!

Picture Features

Taking still pictures when you’re out riding in the middle of nowhere can be difficult on a dirt bike. GoPro made their other helmet cams to take photos, but for the Hero2 they upped the anti with the ability to take 11, 8, and 5 Megapixel photos (It was only 5 MP previously). On top of that, it can take 10 photos per second compared to 3/second the first HD Hero could do. It also has an increased time-lapse mode (0.5).

Video Resolution

While the video resolutions stayed the same (720p and 1080p), GoPro has included more features that movie enthusiasts will love. New for the 1080p & 720p mode, you can choose medium (127 degree) or narrow (90 degree) Field-Of-View, giving you different perspectives of a video.

As for the 960p mode, you can record it in 48fps, in addition to the original 30fps.

GoPro also decided to update the standard def WVGA mode. Don’t think it’s needed? Think again; you can now record footage at an incredible 120fps!! This takes slow-mo helmet cam videos to a whole new level while still keeping it smooth.

Usability

Many people complained that GoPro helmet cams were difficult to operate and navigate through. Now with the upgraded language-based interface, the HD Hero 2 is easier to use than ever. You don’t have to be a genius to figure out how to use one and change modes.

It was often difficult to tell when the camera was recording on previous GoPro helmet cams, so they decided to put 4 LED lights (1 on each side) on, making it easier to see when it’s on.

Motocross Helmet Cam

Want to watch HD footage on your TV? Now you can hook your HD Hero 2 directly up to your HD TV through the added mini-HDMI port.

Sound has always been an issue with helmet cameras, but GoPro has come through yet again by including a new 3.5mm external mic jack to plug in your own microphone.

Compatibility

The first HD Hero you could control by remote using wi-fi. Now on the Hero 2 you are able to preview and playback the video, as well as stream it to the web through wi-fi. Not even the Contour helmet camera can say that.

When all said and done, this isn’t “just another camera” that GoPro put a few blingy parts on. No, they took it to the next level, and it shows in the videos. If you are looking for the best helmet camera on the planet right now, this is it.

Click Here To Buy My GoPro HD Hero2 Helmet Camcorder


 -Tom Stark

How I Built A YZ250F With A Box of Scraps

What do you get with a bin full of dirt bike parts and an eager mechanic looking for excitement and satisfaction? A great project rebuild! If you are a dirt bike grease monkey like me who not only likes riding their bikes but sometimes working on them too then this is for you. I enjoy project rebuilds and love the oh-so greatly anticipated finished product even more. Ever since I got into dirt biking I have gained more knowledge about how they work and how they are put together. So after doing many rebuilds myself I thought that I would share the experience with you fellow riders.

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I bought this 2003 Yamaha YZ250F in pieces as a project bike thinking that I would have some fun and get some more experience putting another bike together over the next month after I bought it. It came needing a complete new top-end at the least. I managed to get one and put the engine together in a reasonable amount of time. I then slapped the engine in the frame and started the process of puzzling the rest of the bike back together; this is where the fun started. It only took a few short minutes of bolting parts on to find that there was stuff missing. The more I put together the more parts I found that were missing or broken, and they were not all at the same time. So one-by-one I had to buy parts that I needed to piece this thing back to its somewhat original form. These parts consisted of, including engine parts, clutch plates, radiator shrouds, timing chain, timing chain slider, a different piston, head pipe, a couple crank bearings, engine/frame mounts, air filter, cylinder head breather hose, chain, gas tank, clutch perch assembly, a shift lever, and maybe a couple other miscellaneous things. Figuring out that we had to find and buy these parts got a little frustrating because we were told that the bike was complete and that it just needed a new top end.

Well, after weeks of picking at my wallet this bike has finally been put together and is running. It just needs a couple things put on to be ride able. So once I get those together I’ll take it out for a spin. The process was long and somewhat miserable, but I think I learned a lesson and gained more experience and knowledge about these modern four strokes that basically took over the world. In the spring, if not sooner, I will be putting on some new bling to make this baby look new, but as of right now it’s a clean bike that runs. Thanks for checking out this rebuild process, and make sure to check back in the near future for another bike rebuild! (If you liked this article make sure to check out my other rebuild, “I Rebuilt My YZ125 In A Closet!?

-Tom Stark

P.S. I might update this article with some pictures and/or video once I get this bike looking good. Questions and comments are welcome.

When I got the bike (as you can see, I had my work cut out for me):

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Pic of the damaged cylinder head:

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After I cleaned it up and the engine was together in the bike:

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Put the wheel and handlebars on:

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The bike put together (added sub frame, carb, electronics, old plastics, seat, exhaust, cables, etc.):

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The finished product…

 

Renewing the ’01 YZ125

So I decided that I wanted to give my dirt bike a good look before I sell it. It originally was my first race bike, but I have bought a newer one, so I will not be needing this anymore. It has been a great bike and very reliable to me. The bike is also very fast. I try to keep my bikes clean and well maintained so that when I sell them it looks nice and I can sell with confidence. My bike did not look the greatest when I first got it, but that’s because it didn’t have any plastic on it. For racing I just put some used plastic on so that I could at least race. Although I am a racer and a younger person, I did not beat the snot out of it and trash it like most people do. I did ride it somewhat fast at times, but I always kept it running and looking pretty clean. Now it is time to sell, so I have brought back the stock look of the bike with the addition of New Plastics and graphics. I have always liked the look of stock bikes better than most aftermarket graphics. I will miss this bike a little, but there’s many more fast bikes to come. Thanks for reading, and stayed tuned for more posts soon!

-Tom Stark

When I Got The Bike
Bike With Some Used Plastics On
Bike With Matching Tank
Bike Refreshed With Cleaning, New Fenders, and Graphics

Schampa Coolskin Balaclava – Best Motorcycle Face Mask


Do you ride your dirt bike on ice, in snow, or just plain cold weather? Give your face some warmth with the Schampa Coolskin Balaclava! No more snosticles, frozen lips, or immovable cheeks after a ride. You can breath better, and with the long neck section, you can tuck it in to help keep the cold wind from blowing down your chest.

No Annoying Seam!!

Have you worn a face-mask with that outrageously provoking seam going down the middle of your entire face?! And no matter what you did, it was next to impossible to keep it in one place while being comfortable… Well, those days are over with the Coolskin winter balaclava face mask with its fully flat-seamed construction. This alone can make it worth it if you want a smooth and comfortable fit on your face.

What Is Silkweight?

It is light-weight and uses silk-like material that is soft on your face. It stretches to fit around almost any size head, making it a versatile and must-have item of protection in your Gear Bag.

Schampa Coolskin Balaclava

Not only is it a one-size-fits-most balaclava, but this Schampa face mask fits under almost any dirt bike, snowmobile, or motorcycle helmet. This makes it a perfect gift to give to friends and family that ride all-year-round.

Dirt bike riding in the cold will be much more tolerable with this winter motorcycle mask.

The Schampa Coolskin Balaclava is currently getting 4.5 stars out of 5 on Amazon, and is on the “Best Sellers” list.

Click Here To Buy My Black Coolskin Motorcycle Balaclava


-Tom Stark