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My 06 rmz 250's radiator hose that connects the right radiator to the right case is a bent by about 20 to 30 degrees and I was wondering if that will restrict the coolant flow. I had to buy a radiator hose not for my bike so that is why it is like that. Will it stop the coolant from flowing or cause any problems?
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This month I want to discuss three easy ways to improve engine cooling for your dirt bike or ATV and explain why they are effective. As improvements are made to an engine that increase its power, the amount of heat the engine will create will also increase. Effectively removing heat from the engine and cooling it is very important as the power output of the engine goes up. The cooler an engine runs, the more power it can produce. There are three ways that the aftermarket attempts to improve the cooling system of a particular engine. 1. Increase flow through the cooling system. 2. Increase the cooling capacity of the radiators. 3. Increase the pressure of the cooling system. Let's dive in. 1. Increase flow through the cooling system The flow through the cooling system can be increased by installing a water pump impeller and housing designed to increase the flow rate of the coolant, such as the Boyesen Supercooler. The reason increasing the flow rate of coolant works is because the rate of heat transfer from the engine to the cooling system is directly proportional to the mass flow rate of coolant. This is thermodynamics jargon, but there are two key parts to consider. First, how much coolant is flowing, and second, at what speed the coolant is flowing. The more coolant that flows and the faster it flows will reduce the temperature difference between the point where the coolant enters into the engine and where it exits. This next part is not quite as intuitive. When the temperature difference between the inlet and outlet is reduced, the average coolant temperature is lowered. When the average coolant temperature is lowered the engine will run cooler. This is why fitting a water pump, which increases the flow of coolant through the engine, improves cooling. Boyesen SuperCooler H2O Pump Impeller 2. Increase the cooling capacity of the radiators Radiators consist of a series of tubes and fins which run from the top to the bottom of the radiator. These are often referred to as the radiator’s cores. As coolant enters the radiator it moves through the series of tubes and heat is transferred from the coolant to the fins. Air passes over the fins and heat is transferred from the fins to the air. This transfer of heat from coolant to air is how radiators reduce the temperature of the coolant. Coolant temperatures can be reduced by upgrading radiators in three ways, by increasing the frontal area of the radiators, by making the radiators thicker, or by using materials with better heat transfer properties for the cores such as those by Fluidyne. For all practical purposes, increasing the radiators’ frontal area and improving the core materials is rarely a viable option for dirt bike applications. This is because there is little room for the radiators to begin with and they are susceptible to damage, making the use of expensive core materials a risky affair. Unfortunately, both of these options are better improvements to make before resorting to increasing the thickness of the radiators. Increasing the thickness of a radiator is not as efficient of an improvement as increasing the frontal area of the radiator. In order for thicker radiators to cool more effectively than their stock counterparts, airflow past the radiators is key. When the thickness of a radiator is increased, air must travel a greater distance through the radiator before exiting. The speed the air is traveling plays a big role in determining how quickly the air heats up as it moves through the radiator. If the air is not traveling fast enough through the radiator, the air temperature will rise and equal the coolant temperature before reaching the end of the radiator. Once this happens, heat transfer stops and whatever portion of the radiator remains will not help with cooling. In order for a thicker radiator to be effective, air must flow quickly enough through it so that the exiting air temperature is at, or better yet, below the coolant temperature. In conclusion, benefits from adding thicker radiators will be more prominent in applications where speeds are relatively high. Whereas in applications where the bike is hardly moving, improved cooling may not be noticeable. Fluidyne Oversized Radiators 3. Increase the pressure of the cooling system The last alteration to the cooling system that can be made is to install a high pressure radiator cap such as CV4. As coolant temperature increases, pressure increases inside the cooling system. The radiator cap is designed to be the pressure release point in the cooling system in the event that too much pressure builds up. This can occur as a result of overheating or a blown head gasket for example. By designing the radiator cap to be the weak link in the system, other parts of the system, such as seals, don’t end up getting damaged from being over pressurized. The radiator cap features a plug and spring on its underside. The spring is designed to compress once a certain pressure is reached, at which point the plug will move upwards and uncover a pressure release hole where excess pressure will be vented. CV4 High Pressure Radiator Cap The coolant’s boiling point and ability to conduct heat are necessary factors in understanding why a high pressure radiator cap can help improve engine cooling. Water alone boils at 212°F (100°C) while a 50/50 mix of water and antifreeze boils at 223°F (106.1C). Radiator cap pressure designations are usually advertised in bar, with most stock radiator caps designed to withstand pressures up to 1.1 bar (16psi). The more pressure a fluid is under, the more difficult it becomes for the fluid to vaporize, and the higher its boiling point becomes. When water is under 1.1 bar of pressure, the temperature water will boil at is 260°F (127°C) while a 50/50 antifreeze mix will boil at 271°F (133°C). By installing a radiator cap designed to withstand higher pressures, an additional increase in the coolant’s boiling point will be seen. High pressure caps are usually designed to withstand 1.3 bar (19psi) of pressure. This 0.2 bar (3psi) increase in pressure over the stock system will increase the boiling point of water or antifreeze by 8.7°F (4.83°C). This will then bring the boiling point of pure water or a 50/50 antifreeze mix to approximately 269°F (132°C) and 280°F (138°C) respectively. While this small temperature increase alone won’t do a lot for your engine, coupling a high pressure cap and using coolants with better heat transfer properties can do wonders. Antifreeze (ethylene glycol) alone is not an inherently good conductor of heat. In fact, pure antifreeze conducts heat about half as well as water, while a 50/50 mix of antifreeze and water conducts heat approximately three quarters as efficiently as pure water. This means a cooling system using a 50/50 mix of antifreeze would have to flow faster than a cooling system filled with pure distilled water in order to achieve the same cooling efficiency. What this means for you is significant cooling gains can be made by using distilled water and an additive called “Water Wetter” in place of an antifreeze-water mix. Water Wetter is an additive that improves water’s “wetting” abilities (another whole subject), adds corrosion resistance, and slightly increases the boiling point of water. A high pressure radiator cap in conjunction with distilled water and Water Wetter as the coolant is by far the best route to go for high performance applications where freezing is not an issue. For applications which must still be resistant to freezing, the antifreeze-water ratio can be altered in favor of mixtures incorporating more water than antifreeze so that the cooling efficiency of the mixture is improved. Just bear in mind the freezing point of the mixture as it is thinned with water will be reduced, so you will need to pay close attention to the environment you are operating in so that the coolant is never susceptible to freezing. A frozen coolant system can ruin an engine and makes for a very bad day! I hope you enjoyed this post on three easy ways to improve your engine’s cooling. Feel free to add your engine cooling tips, tricks & questions in the comments section below.
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so i have made template for xr6xx heads - single and dual carb versions. planning to have them water jetted, but unsure what aluminum to use - my thoughts lean toward: 3xxx Series Alloys – (non-heat treatable – with ultimate tensile strength of 16 to 41 ksi) These are the aluminum / manganese alloys (manganese additions ranging from 0.05 to 1.8%) and are of moderate strength, have good corrosion resistance, good formability and are suited for use at elevated temperatures. One of their first uses was pots and pans, and they are the major component today for heat exchangers in vehicles and power plants. Their moderate strength, however, often precludes their consideration for structural applications. These base alloys are welded with 1xxx, 4xxx and 5xxx series filler alloys, dependent on their specific chemistry and particular application and service requirements. but i think the non-heat treatable is a knock esp if you are doing cloverleaf heads that really should be heat treated before surface finishing and machining... so does that point to: 6XXX Series Alloys – (heat treatable – with ultimate tensile strength of 18 to 58 ksi) These are the aluminum / magnesium - silicon alloys (magnesium and silicon additions of around 1.0%) and are found widely throughout the welding fabrication industry, used predominantly in the form of extrusions, and incorporated in many structural components. The addition of magnesium and silicon to aluminum produces a compound of magnesium-silicide, which provides this material its ability to become solution heat treated for improved strength. These alloys are naturally solidification crack sensitive, and for this reason, they should not be arc welded autogenously (without filler material). The addition of adequate amounts of filler material during the arc welding process is essential in order to provide dilution of the base material, thereby preventing the hot cracking problem. They are welded with both 4xxx and 5xxx filler materials, dependent on the application and service requirements. i am not conversant with solution heat treatment. i always thought the al in heads had a fair amount of silicon... so anybody got thoughts of what alloy best to use? i am thinking that maybe this should become a group buy. let me figure out the yield from a sheet of aluminum and the cost of waterjetting and then we can see if this is something TT members want in on. i can't imagine it will cost much - no upcharge, just share the cost of material and jetting - i would think the more we cut, the cheaper it gets per unit. neil
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Hi, I drained the coolant out of my ‘19 Yz125x and was wondering how to refill it? There is a bleeding screw in the cylinder head as far as I know, do I need to use it? Or just fill up like this? Thanks!
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I was sitting in class daydreaming about my bike when it occurred to me; Why haven't I seen more people running two radiator fans for hard enduro? I mean it's a bit overkill and might take away from learning to be a more efficient rider but there have to be people out there who do it? I might be mistaken. Is it for electrical reasons, or is it just not necessary? Just a thought...
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Hey, I have this '09 YZ250F that started continuously leaking coolant out of the weep hole (underneath the water pump housing) while it was running and later while it wasn't running. From some searching this forum, I understand that it's probably a bad seal. So my question is what all do I need to replace to fix the issue and what should I replace while I'm in there? Here's the schematic https://www.rockymountainatvmc.com/oem-schematic/6 I appreciate any input, thanks in advance!
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Thought this mod will be straight forward, but no. Bought a KTM fan for my 450EXC, it come in a nice box, including the fan, wiring, thermalswitch, manual. Trial fit the fan on my right radiator as manual said, looks good: But then I found there are something unlike what it should be... 1. There is no matching available power connector on my bike 2. There is no where on both radiator for the thermalswitch to screw in 😢 In the below photo, circle #1 is the power socket from the fan, circle #2 is the connector to the thermalswitch. Manual said: Current wiring harness, no available outlet: Example of one radiator, no nozzle for thermalswitch: Any recommendation pls? Thanks.
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Hey guys, I got a 2002 rm125. I recently rebuilt the top end and water pump. For the first start of the bike I only idled it for about 1 minute or even less. No throttle at all. I put the bike back in the garage and came back a couple days later to see all the coolant in the bike was spewed out of the overflow. When I rebuilt the water pump, I spun the impeller while it was out of the bike and it had some resistance to it. Anyone know what is could be?
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Just inquiring if anyone out there ever put some type of a cooling fan on their XL600? I have a 1987 that I've always looked for ways to keep cooler. I have a TRX300FW that we added a 7" fan to and it works great, but that frame had lots of room to fit one in. Not a whole lot of room on the XL to add anything, but I've thought about maybe fitting something small behind the headlight shroud angled down.
