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The FJR "BlowJob" - Coolant Flush/Refill
System Category: Engine
Activity Type: Scheduled Maintenance
FJR Model Year: 2003  2004  2004 ABS  All model years
Date Submitted:July, 2004

The FJR "BlowJob" - Coolant Flush/Refill

The FJR's cooling system leads a rough life. It's important that the coolant level be maintained within spec, and flushed/refilled at least within the specified Service Interval. Personally, I would never go past 12 months without flushing/refill. Don't neglect this system.... Bad Things will likely result if you do.

There are a number of ways to go about servicing the cooling system. What follows is the description of the FJR "Blowjob", a cooling system flush/refill technique that was taught to me many, many years ago by a legend in the Endurance Riding arena, Ron Major. Ron was sadly taken from us by a heart attack in 1997. RIP, Ron.

The purpose of the FJR Blowjob is to remove the vast majority of old coolant before you start flushing the system with water. You then use this same technique to remove the vast majority of the water used for flushing, prior to pouring in your fresh coolant.

Materials Needed:

Below are pictured the very few items you will need for this maintenance evolution:

  • 1/4"-drive 8mm and 10mm socket
  • 1/4" ratchet with extension
  • 4mm T-Handle or allen wrench for bodywork removal
  • A gallon of your Coolant brand of choice. Do ensure that whatever brand coolant you choose, it is silicate and phosphate-free. This is extremely important. If your nervous about using other brands, you certainly can't go wrong with Yamaha Coolant. Personally, I have used the pictured Havoline Dex-Cool Extended Life coolant for the past 8 years on 5 different bikes for a combined 350,000 miles, and never a single problem. Havoline Dex-Cool is The Shit.
  • Four (4) gallons of de-ionized, de-mineralized purified water. Do NOT use tap water, or even bottled drinking water (which contains trace minerals).
  • Approximately 1-2 feet of 5/16" I.D. (and ~5/8" O.D.) fuel line
  • Not pictured are the bucket to hold old fluid, and an appropriately-sized funnel for refilling coolant at the radiator cap.

Overview: Basically, this maintenance involves draining old fluid, flushing the system three (3) complete times, then re-filling with fresh coolant. Begin by pre-mixing your coolant to the appropriate 50/50 mixture. Take one of your gallons of de-ionized water and pour exactly 1/2 gallon of it into a separate, clean container. Now pour exactly 1/2 gallon of your fresh antifreeze into the water jug, and the clean water into the coolant container. You now have two full gallons of fresh coolant. One gallon will be used to "flush out" the very last water flushing, and the second gallon with be used to actually replace the old coolant.

Step 1: Start this maintenance procedure with a cold engine. Remove the right side cowling to expose the overflow reservoir, and the left rear black plastic dash panel to expose the radiator cap. Although not absolutely necessary, I also removed the left side panel, which allows you to better "flex" the cowling bodywork near the radiator cap as you go about inserting the funnel and fuel line during this procedure.

Step 2: Disconnect the lower drain tube located at the bottom of the overflow reservoir, and drain the old coolant into your bucket. Reconnect the tube when you are done. 


Step 3: Remove the radiator cap. Now position your bucket appropriately, and use your 8mm socket to remove drain plug located immediately below the water pump (yellow arrow point to where drain plug resides). Use caution here as the fluid will initially come streaming out at a pretty fair rate. Be prepared with your drain bucket before completely removing the drain plug.  


Step 4:Now it's time to perform your Blowjob! First drape a heavy rag over the coolant drain plug opening. If you fail to do this, old fluid will come flying out of the drain plug and across the garage floor when you go to perform a proper Blowjob.

Now insert the fuel line into the radiator cap opening as seen below. The 5/8" O.D of the fuel line makes a fairly good seal if you insert it deep in the neck of the filler cap, but you might find you need to seal it up further as best you can with you hand/fingers. 


Now give a mighty blow on the other end of the fuel line, and watch how much more fluid you can force out! Blow several times until you don't see/hear any more fluid coming out.

Step 5: Now it's time for the painful flushing game. Take one gallon of your de-ionized water and fill the radiator to the very brim. Put the cap back on, start the bike, and let it run long enough until the fan comes on at least once (which is four bars on the temp gauge). This ensures the thermostat is fully open, allowing any residual old coolant to be thoroughly mixed with the fresh water.

Step 6: Let the bike cool down enough that you can remove the radiator cap uneventfully. Remove the drain plug again to drain this flushing, obviously using care to avoid burning yourself if the water is still hot (which is why you should wait to let the bike cool down sufficiently!) As the flushing drains, you will still see it a definite green color from some old coolant that still "trapped" in the cold motor, but is now mixed with the fresh water

Step 7: Repeat the Blowjob technique to remove as much of this initial flushing as possible. Re-install the drain plug.

Step 8: Repeat Steps 4-6 again. This time, the flushing should be a pretty faint green in color, indicating you are indeed flushing out the old coolant appropriately. Do a good Blowjob technique here.

Step 9: One last, final flush: repeat Steps 4-6 one last time. This time, the flushing that you drain had better be essentially clear. If it still shows a good hint of green, you probably ought to consider yet another flushing. When all done, remember to again re-install the drain plug.

Step 10: Now we're getting close. Take many towels and COVER YOUR FAIRING everywhere around the radiator neck opening (coolant + bodywork paint = Badness). Insert the funnel in the radiator cap opening as seen below, and carefully fill the radiator with your fresh coolant:


Step 11: Painful as it is, you should once again let the engine come fully up to temp, let it cool down, then drain the system again. Don't forget to perform another Blowjob, the last one of this exercise. Re-install the drain plug and torque to specs. The purpose here is to remove all traces of the flushing as possible, which prevents the 50/50 mixture from being diluted with the old flushing water.

Step 12: Almost done, really! Take your last gallon of fresh coolant, fill the radiator to the very brim for the last time. Use your 10mm socket to remove the black plastic trim covering the top of overflow reservoir opening. Now pour some fresh coolant up close to the "max" line on the overflow reservoir. One, final, last time, run that engine and get the fan to kick in at least once. Now let the engine *completely* cool down.

Step 13: When the engine is again *totally* cold, open up the radiator cap. You should see that the some amount of "burbing" has occurred, and the coolant level is no longer at the very top. Top it off once again. Check the overflow reservoir level, as fresh coolant may have been sucked back into the system upon cool-down. I keep mine somewhere around 2/3 the way between "min" and "max" levels.

Done! Reassemble the bike. Check for any leaks near the drain plug (Yamaha recommends replacing the copper sealing washer on the drain plug, but I found that unnecessary). Dispose of the old coolant/flushings properly. Go ride.


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