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Discussion Starter #1 (Edited)
You guys were right. Low filthy coolant and radiator fins, low coolant levels, and running too
lean. From riding so much on these repulsive streets..☺
Its definately time for a cooling system flush and high pressure radiator cap.
67852

67799


Right before the stunt, i went to my parts guy. He gave me purple ice coolant optimizer. Also, I am back on my meds. FIXED!!!
TY FAM!
67715
 

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Have you checked the coolant reservoir and radiator levels? Both should be checked with the engine cool.
 

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Being up to date on services and recalls doesn't mean the radiator fluid levels have been checked. Has the coolant been changed recently? Any thing at all different that would have effected the coolant system?
 

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The R3's not prone to over-heat. I have a 2015, and even in 90degree rides, it won't kick on the fan until I'm finishing up my ride and letting it idle for a few minutes while I'm parking it. I guess it could be a faulty thermostat, or a damaged impeller shaft not circulating fluids, but that's a long shot. Possibly a bad sensor or sending unit to the gauge and or fan. Like I said, this isn't a common problem, so I'm not much help. I have a link below if you care to look through previous discussions. Maybe something there I've overlooked. And maybe someone else will chime in to give better advise. Good Luck.
 

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Discussion Starter #7
The R3's not prone to over-heat. I have a 2015, and even in 90degree rides, it won't kick on the fan until I'm finishing up my ride and letting it idle for a few minutes while I'm parking it. I guess it could be a faulty thermostat, or a damaged impeller shaft not circulating fluids, but that's a long shot. Possibly a bad sensor or sending unit to the gauge and or fan. Like I said, this isn't a common problem, so I'm not much help. I have a link below if you care to look through previous discussions. Maybe something there I've overlooked. And maybe someone else will chime in to give better advise. Good Luck.
Thank you for your time.
 

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Yes it has coolant. I noticed it ran warmer when i spec torqued my axle nuts recently. The weather has been hot and ive put on a few pounds. Lol!
Torquing the axle nuts should have ZERO effect on engine temperatures. It sounds like you have a cooling problem. Check the radiator (not just the overflow). It could be as simple as a bad radiator cap-
 

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Im not rich or a great mechanic, so i guess ill just run her till she blows up.
Ok, that's off a bad start to try fix anything. Motorcycles are pretty simple machines. You don't need to be rich or a great mechanic to problem solve.

I rode yesterday in temps approaching 100° and the fans came on a few times at stoplights, but not once did the temps rise above 3 bars. Never.

When I got my bike a few months ago, it had about 4500 miles on it and it had all of the factory/dealer recalls done by the previous owner, including the coolant hose recall. Within the first week, the bike started to show signs of overheating on my afternoon commute home. And I mean full bars with the last one blinking while sitting stationary at stoplights. When I got home, I ordered a jug of Engine Ice and planned to do a full cooling system refresh. Turns out, the dealer that did the coolant hose didn't refill it properly, and left the cooling system about half full of straight antifreeze.

I took off all of the fairings to make it easy to work on (there are a couple of good FAQs out there if you need help). You only need a few metric hand tools to work on the R3. 4mm and a 5mm allen wrenches, 8, 10 and 12mm sockets, Phillips or JIS screwdrivers and you can take much of the bike apart with those tools and a few others.

Drained the whole system into a drain pan, then flushed the system once with distilled water. Got it full, burped out the air bubbles, ran it a few minutes then drained the water. Once it was completely empty, I did it again with distilled water. I actually filled and drained until the water coming out was clear. Took about a half gallon of water.

Two things—the filling process was made easier by using a tall 500ml graduated cylinder that I have in my shop for tasks just like this, but filling slowly from a red Solo cup would work, too. I also used the water flushing process to figure out how to properly "burp" the system of air pockets. I filled slowly, sat on the bike and rocked it back and forth a few times, and topped it off. STG has a video on Youtube that can also help show you how the process is done.

Once the bike was flushed thoroughly, I started the new coolant fill the same way I had done the water. Slowly, filling the radiator until you are close to the top of the radiator neck. Squish the hoses slowly from the bottom-up on both sides of the bike and watch the coolant level. Rock the bike a few times, and the level will reduce even more. Top it off. Fill the overflow tank halfway with coolant.

Run the bike a few minutes at idle, watching the temps of both coolant hoses. I used an old temp gun I had from my RC racing days to check the hose temps at the base of the engine inlets/outlets to make sure they were relatively similar. Let the fans cycle while at idle, and watch the temp gauge. If it jumps past 3 bars, shut it down. Top off the radiator again until it's full. Squeeze the coolant hoses again to burp the air out once the temps have come down a bit.

Now put the radiator cap back on after everything is topped off, and run the bike and get it up to operating temps (3-bars). Again, if it goes to 4, shut it down and wait until it cools off before opening up the radiator cap again. DO NOT REMOVE IT WHILE HOT.

Once you have the fans cycling a couple of times and the bars staying at 3 without going past, you're done. Button it all back up and go ride. I would check the level on the expansion tank after the first ride, and make sure the level of coolant is right in the middle of LOW + HIGH.

The R3 does NOT run hot unless something is wrong. If you throw up your hands and ride it until it blows up, you're not going to have a motorcycle to ride much longer. Don't do that.


The cooling system is pretty simple. It's a few hoses, a radiator, an expansion tank, a thermostat that controls when the coolant is let into the engine, fans and coolant. If the bike is overheating, start with the easiest and cheapest to fix first—coolant level. Then work from there (thermostat, hoses, radiator cap, etc). It's all easy stuff to fix.
 

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Discussion Starter #12 (Edited)
My dood,
If i go in all gung ho and start ripping my bike all apart theres a good chance it will never run again.
Thanks for the advice bro, but im just gonna take it to a mechanic.
 

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Get him to check the fan temp sensor and the radiator cap. They are normally the culprits for overheating bikes. I think it's the radiator cap, personally, as your fans are turning on at temp.
 

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Get him to check the fan temp sensor and the radiator cap. They are normally the culprits for overheating bikes. I think it's the radiator cap, personally, as your fans are turning on at temp.
Would a bad radiator cap cause the engine to over-heat.. or loose coolant that causes the over-heating? My understanding is the cap is designed to allow the system to build some amount of pressure, allowing the system to run hotter than normal ambient pressure, before reaching boiling temperatures.
 

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Would a bad radiator cap cause the engine to over-heat.. or loose coolant that causes the over-heating? My understanding is the cap is designed to allow the system to build some amount of pressure, allowing the system to run hotter than normal ambient pressure, before reaching boiling temperatures.
A bad radiator cap could either overpressure the system building up heat in the system potentially causing leaks in the cooling system (ie. hoses, radiator fins) or not pressurise the system at all, causing the coolant to flow into the overflow tank prematurely and lose fluid that way. Both ways, the cooling system can cause temps to rise, be it due to insufficient coolant or unreleased pressure. Or it could be air in the coolant system, but I find it unlikely as he stated his temps were fine before, and I assume he has not laid down the bike before the change in behaviour.
 

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Discussion Starter #16
Hey guys im here. Thanks for trying to help me out. Im so distraught that my bike is not happy. It has not been laid down since the temp increase. Not sure how to check a fan sensor, but im happy to check the radiator cap. Do i have to rip my bike apart to check these things? What does a bad radiator cap/ fan sensor look like? Im not a noob ok. Ive been riding a long time. Im just not the greatest mechanic ever. Dont judge.
 

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Would a bad radiator cap cause the engine to over-heat.. or loose coolant that causes the over-heating? My understanding is the cap is designed to allow the system to build some amount of pressure, allowing the system to run hotter than normal ambient pressure, before reaching boiling temperatures.
I had a 2016 KTM RC390 with a bad radiator cap (a known problem). It wouldn't hold pressure. When it got hot, it would puke coolant out into the overflow tank, but wouldn't draw it back in after it cooled down. I bought a better quality (aftermarket) radiator cap, and never had another problem. I knew it was bad when I removed the radiator cap, and the radiator was barely 1/2 full :rolleyes:-
 

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When i got my recalls done about 9 months ago.
I ride about 7k miles a year.
Do you think i should attempt a coolant change?
Did you request for new coolant? FYI the recall does not include new coolant. I believe most dealers will just reuse the old coolant because Yamaha will not pay for it.

I would just buy one of those coolant tester on amazon for 5 bucks and see if your coolant is still good.
 
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