This next section will dive into the engine portion of our bike prep series. This section can pertain to just about every motorsport category for preparation. As you will see in the pictures and our desert bike we used various components that we have found work. Not all are trial and error but what the factory teams like JCR Honda and KTM as well as the Factory Kawasaki teams use. These teams spend countless hours and huge sums of money testing and beating their bikes in the desert to make sure the products they use work and most importantly last in a desert setting. We have researched these tricks of the trade and yes some of it has been trial and error but you can make the decision on what you can spend or what you think your machine can use. Just remember, and as we have learned the hard way, you can never be over prepared.
#1- Hoses for the radiators. We use a neoprene silicone hose set from CV4. You can get these in just about any color and for any bike. These have a tough side wall and are very strong under high heat conditions. If you notice on picture “A” we even went as far as to insulate the lower hose from the exhaust heat. Anything helps and just little things like this do make a difference. One other little trick we use is to smear a thin coat of high heat silicon around the pipes before installing the hoses. This will help make a nice seal.
#2- The next item is radiator braces. See picture “B”. We are using a set from 7602. These braces are really strong, look good and for the cost can really save your tail if by chance you do a digger and smack your radiator on a rock. There are a dozen different manufactures for these braces. All different types, sizes, shapes and costs. Another reason we went with these particular braces is that these incorporate an opportunity to mount our radiator fan.
#3- Inside the engine. We thought this is a good time to discuss the internal parts and adjustments on the engine. We want to start by asking how many times have you ran your bike in a moto, enduro or other event to return to your shop and the next day the bike seems hard to start. The culprit is usually low compression caused by the valves going out of adjustment. This is not an uncommon phenomenon on racing machines. These bikes are high revving and will need periodic adjustments to keep the engines horse power at its premium and compression at its highest. From time to time you will need to have the valves checked for tolerance. Its easy, really. First check with your manual for this procedure. Once the valve cover is removed you will see the valve train with the two cams, one intake and one exhaust. Rotate the engine slowly until the cam lobs are facing away from the springs. Take your feeler gauge and the size needed and slide it under the cam against the valve spring. If you have to make an adjustment, and depending on your engine, you will have to remove the cam shaft to replace the desired shim size. The cam will then have to be replaced in its proper location for timing. You will have to have a manual for this operation or see your nearest dealer. After you make the necessary adjustments always rotate the engine slowly to make sure your cam timing is correct. NEVER just try and start the bike without doing this. If you have it out of time the valves my hit the piston and cause damage to the valves. Once you tackle this once or twice you will have it down.
#4-Heat rap. Picture “C”. We use a titanium heat rap over our exhaust to direct heat away from the engine. This has been a huge engine saver in long races. Think about this for a second. If the engine is creating heat out the exhaust, and like most bikes the exhaust is very close to engine components, wouldn’t be smart to say that those parts will be affected by that heat? How about a radiator hose, or a fuel line near the pipe for an example. Try this test. Get one of those digital thermometers, Harbor Freight and even Wally Mart sells them, anyway, go out for a ride. Get the engine temp up. Check the temp on various engine components, like radiator hoses exhaust and even your engine case. Then rap the exhaust and test again, walla you just reduced engine component temps by 10-15 degrees or more. Engine heat WILL cause loss of horse power! You can buy this rap at any hotrod store or auto store near your shop. Don’t be scared away from the cost for a roll. It runs about $25.00 a roll and enough to do a bike exhaust. After cutting the rap to length for the section of pipe you’re working on, drop it into hot water for a couple of minutes. Then start your rap. Fold the end under itself and tie a piece of safety wire around it and the pipe to hold it in place. Pull it tight while rapping it around the pipe. Finish the rap like you started using another piece of safety wire to hold the rap in place. You can also wrap your fuel line with some aluminum heat wrap and zip tie it in place. This will keep your fuel cooler which will keep your engine cooler, which will create more horse power.
#5- Carburetor. Picture “D”. Ok art fans, carburation is just that. It’s an art to get it right. It’s a pain and can really play havoc with your engine performance as well as your attitude. We are going to start this will only some basic tuning you can do that will make a huge difference to your power and the bikes performance. If you follow a few easy steps you will notice the difference. Now disregard this all together if your bike is fuel injected. So, loosen the two clamps on your carb. One on the front and one on the rear. You may have to remove the tank to continue. Gently rotate the carb so you can get at the bottom of the carb. Carefully remove the screws holding the float bowl. Once this is done you will see a couple of brass jets. The larger jet will need to be removed. Locate the size of jet you have and write it down. The next few steps is where the art of carburation comes in. Every bike is a little different. Has different pipes, engine mods etc. So we are going to go with a stock motor, and an aftermarket exhaust, like say an FMF of a Leo Vince like we have on our desert bike. Our stock main jet on our Husqvarna 510 was a 176. Here in Colorado we now use a 182 main and at sea level like in Baja we can bump it up to a 190! Huge power gains can be achieved by jetting your bike. Some big advantages on proper jetting is of course more horse power and better engine response. And of course cooler engine temps! A good rule of thumb is ‘more air, more fuel, more horse power’. You might have to play with these setting a few times to gain the best performance. Go out and ride the bike, feel how it pulls. If it pulls hard, doesn’t lag off the throttle and has no flat spots. You probably got it. Another little option is a good air filter. There are a million of these out there. We use nothing but NoToil filters, cleaners and filter oil in our bikes. They work and work well, even in the worst desert conditions. One more thing on filters- we always run axle grease around the contact area of the filter to the air box (see picture). This helps seal the air filter to the air box. One more thing we installed on the bike is a filter for all our drain hoses. Carburetors will suck small particulates up the drain tubes under high revving conditions. For instance in Baja the silt is so fine it will pass through the lines and collect in the float bowl turning the gas to mud. Not good unless you want to be cleaning your carb in the middle of the desert. It’s a cheap insurance policy.
#6- The next portion is ‘Coolant’. Coolant for your bike is always important. You want to make sure you have a proper level or type of fluid. There are a few different kinds of fluids you can use and we will discuss 4 of these with the pros and cons of each. First, check your fluid recommendations in your bike’s manual. Some engines require special chemicals to help protect against corrosion. The first product we’ll discuss and we use in our desert bikes is an oil based fluid called EVANS Waterless Coolant. This product is the lowest temp coolant on the market. It also lubricates the water pump. And since there is no water, there’s no need for antifreeze in the winter. The best part of this product is it doesn’t produce any pressure in the radiators. In a long race “if” something would cause a leak in the radiators, a rock or a crash, it won’t spray all your fluid out causing you to DNF. The second product is Redline’s ‘WaterWetter’. This is an additive you use with water. This product “IS NOT ANTIFREEZE” and the cooling temps are somewhat better then antifreeze, but not by much. It will also build pressure in your radiators because of the water. The third product is antifreeze. The good old standby. It won’t freeze up in the winter and it cools your engine (kinda) and that’s about it. But for a few dollars more you can get better coolant and lubricant for your machine. Fourth, there’s water. Good to drink for your hydration, not for your engine’s hydration. Enough said.