spalkin
Well-known member
OK, guys and gals. Please stop giving these “********” to your bikes. Sounds like someone thinks it’s cute to be able to call something a “*******”. Ron Major (rest in peace) may have been a great guy, but he really can’t help us here. The factory carefully designed the cooling system to be serviceable by a tech who could get a thorough flush and fill done with no comebacks. Here’s how they did it.
Everything slopes down, from the cylinder distribution pipe at the top of the head, down through the valve at the end of the throttle body, down through the very bottom of the cylinder bank, into the radiator and then down and out through the drain bolt at the bottom of the water pump. That’s as low as it gets. When you open the radiator cap and remove the drain bolt, everything just falls right out of it. Except for about a half a cup in the oil cooler, and some residual that can’t possibly make it out by gravity alone. You’re going to help it.
When you snug the drain bolt in place and funnel in some nice, fresh distilled water until it starts to come out, wait. What you’re waiting for is the water level to reach itself up and around the back of the thermostat. It does this because at the very top of the thermostat (inside the passage), there’s a small purge hole so the system can equalize itself. Top it off and gently rock the bike a couple of bumps to the left and a couple to the right, top it off again and now you’ve saturated the entire system with fresh, clear water. No waiting necessary! Open the drain bolt and hold your pan out (you should be getting pretty good at this by now). Check out that green water! You just about caught all the residual in the system. Just about, though. You want do that a couple of more times. By the third one you should be seeing perfectly clear water.
You’ve done it. That entire system has nothing in it but water. You got around the back of the thermostat. You went up through the bottom of the cylinder bank, all the way up through the head, out the pipe at the top of the head. You got the lines going to the throttle body. You got the hose leading up to the front of the thermostat and you even got the oil cooler, because water falls through it from a line off the radiator and then an exit that joins the return hose to the drain bolt.
Now go mix your 50/50 and cascade that fresh stuff in there and you’re golden! You never saw a hot engine. You saw how crystal clear the water was, and all you had to do was get a look at the radiator cap and the drain bolt. All the clear water had to do was touch old antifreeze mix and it stuck, then you drew it all out. Three times without breaking a sweat. I guess you can blow air through it if you want to, but it’s not necessary. If you were really insane, like me, you could add just a touch more solid antifreeze to your mixture to compensate for the ¾ cup of pure water left in places of the system, but it’s not enough to worry over.
In cars it’s really easy to get behind the thermostat. You just pick a hose off the heater core, point it down, connect a hose to the inlet of the heater core and turn on the water. With the radiator open and cap off everything just gets blown out of it. On the FJR1300 we’re lucky because there’s actually a line that runs off the main system to do another job. That’s the line that goes to the valve at the throttle body from the top of the cylinder head. If you were to install a Tee into that line and connect in a hose, you could simply take a pump-up garden sprayer with the nozzle cut off, fill it with three gallons of distilled, connect it in and just flush everything! I thought about doing that, even bought the brass Tee and all fittings, but fill and dump works just as well. I still may mess with it
Everything slopes down, from the cylinder distribution pipe at the top of the head, down through the valve at the end of the throttle body, down through the very bottom of the cylinder bank, into the radiator and then down and out through the drain bolt at the bottom of the water pump. That’s as low as it gets. When you open the radiator cap and remove the drain bolt, everything just falls right out of it. Except for about a half a cup in the oil cooler, and some residual that can’t possibly make it out by gravity alone. You’re going to help it.
When you snug the drain bolt in place and funnel in some nice, fresh distilled water until it starts to come out, wait. What you’re waiting for is the water level to reach itself up and around the back of the thermostat. It does this because at the very top of the thermostat (inside the passage), there’s a small purge hole so the system can equalize itself. Top it off and gently rock the bike a couple of bumps to the left and a couple to the right, top it off again and now you’ve saturated the entire system with fresh, clear water. No waiting necessary! Open the drain bolt and hold your pan out (you should be getting pretty good at this by now). Check out that green water! You just about caught all the residual in the system. Just about, though. You want do that a couple of more times. By the third one you should be seeing perfectly clear water.
You’ve done it. That entire system has nothing in it but water. You got around the back of the thermostat. You went up through the bottom of the cylinder bank, all the way up through the head, out the pipe at the top of the head. You got the lines going to the throttle body. You got the hose leading up to the front of the thermostat and you even got the oil cooler, because water falls through it from a line off the radiator and then an exit that joins the return hose to the drain bolt.
Now go mix your 50/50 and cascade that fresh stuff in there and you’re golden! You never saw a hot engine. You saw how crystal clear the water was, and all you had to do was get a look at the radiator cap and the drain bolt. All the clear water had to do was touch old antifreeze mix and it stuck, then you drew it all out. Three times without breaking a sweat. I guess you can blow air through it if you want to, but it’s not necessary. If you were really insane, like me, you could add just a touch more solid antifreeze to your mixture to compensate for the ¾ cup of pure water left in places of the system, but it’s not enough to worry over.
In cars it’s really easy to get behind the thermostat. You just pick a hose off the heater core, point it down, connect a hose to the inlet of the heater core and turn on the water. With the radiator open and cap off everything just gets blown out of it. On the FJR1300 we’re lucky because there’s actually a line that runs off the main system to do another job. That’s the line that goes to the valve at the throttle body from the top of the cylinder head. If you were to install a Tee into that line and connect in a hose, you could simply take a pump-up garden sprayer with the nozzle cut off, fill it with three gallons of distilled, connect it in and just flush everything! I thought about doing that, even bought the brass Tee and all fittings, but fill and dump works just as well. I still may mess with it
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