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Cap should have a number listed on it. (generic image) That'll be the cooling system pressure.
Font Nickel Circle Silver Metal


This is opening pressure for my system. (yours may be different)
Rectangle Parallel Font Circle Number
 

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It is being screwed on correctly. not have a pressure gage on my cap. Do you recommend getting one? Also, I plan on draining my coolant and inspecting the water pump again as well as the hoses when I have time.
Keep an update. If it’s not overflowing due to overheating it must be a pressure thing, rad cap or similar imo
 

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Discussion Starter · #24 ·
Keep an update. If it’s not overflowing due to overheating it must be a pressure thing, rad cap or similar imo
I do not believe it is from overheating because it is able to cool itself down if idling. I doubt it is the radiator cap since I replaced it and it is still having the issue (unless the new one is faulty too). I do notice that when the coolant is pushed into the reservoir, it is very hot, almost boiling. I am not sure if it is due to the vacuum being broken or if it just got shot out before it had a chance to cool down. I have not seen any leaks at all. Other than a head gasket, is there any other way pressure may be building up?
 

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I do not believe it is from overheating because it is able to cool itself down if idling. I doubt it is the radiator cap since I replaced it and it is still having the issue (unless the new one is faulty too). I do notice that when the coolant is pushed into the reservoir, it is very hot, almost boiling. I am not sure if it is due to the vacuum being broken or if it just got shot out before it had a chance to cool down. I have not seen any leaks at all. Other than a head gasket, is there any other way pressure may be building up?
Air in the system. When you refill the radiator are you burping the system properly? Leaving the cap off and letting the bike run and get to temp. You’ll see bubbles escaping through the radiator when the cap is off. If not and there is air in the system when it gets hot the air expands it can cause high pressure and poor cooling. It will overflow forsure if there’s air in the system
 

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Discussion Starter · #26 ·
Air in the system. When you refill the radiator are you burping the system properly? Leaving the cap off and letting the bike run and get to temp. You’ll see bubbles escaping through the radiator when the cap is off. If not and there is air in the system when it gets hot the air expands it can cause high pressure and poor cooling. It will overflow forsure if there’s air in the system
Yes I have a few times. Is it possible there is an air bubble stuck somewhere deep which I am unable to remove? I read online that these bikes do not need to be burped due to the cap being at the highest point of the system?
 

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Yes I have a few times. Is it possible there is an air bubble stuck somewhere deep which I am unable to remove? I read online that these bikes do not need to be burped due to the cap being at the highest point of the system?
I’ve never heard that but you could be right, I don’t know everything lol but I’ve noticed on my bike over heating when I didn’t. I don’t think it’s a problem if you burp it till the thermostat opens, your overflow tank will displace the last bit of the air with the coolant in the overflow at that point. But I don’t think there could be an air bubble trapped that hard to get rid of. It’s a weird problem
 

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Discussion Starter · #28 ·
Hey everyone, I apologize for the very late update. I took my bike to another mechanic and he found out that it was in fact a blown head gasket. It was a very minor leak which is why it only happened at high RPMs. I really do appreciate all of your help!!
 

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Thanks for the update. 👍
Yeah can't keep riding when it's overheated... treat it the same as running out of oil and shut it down immediately; don't restart until enough fluid is added.
 

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I recently changed mine. Not sure what a shop would charge but at least you caught it in time. It’ll be right back to the way it should be with a new one.
 

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May have warped the head and/or block. Would have to lookup the tolerances for piston head to valve clearances. If already tight, shaving might prove risky(?) and require a tune.
 

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May have warped the head and/or block. Would have to lookup the tolerances for piston head to valve clearances. If already tight, shaving might prove risky(?) and require a tune.
With a slight leak let’s hope it’s just a gasket blow out. A serious resurface would need some other things adjusted but I got away with a cometic head gasket with 6 thousands thinner then oem and no need to cut the pistons or re shim. And if it was rode a lot with that blow you can also have piston wall cracks. But I think this case he got lucky catching it. Worse case he may need some new plugs and a throttle body sync after the new gasket.
Also YOU CAN REUSE THE OLD HEAD BOLTS. A lot of people will say they NEED replaced. They don’t. They tighten down in 2 sequences with different torque numbers. An experienced shop can handle this.
 

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Hello, I am new here so please let me know if I am doing anything incorrectly.

Recently while riding, I noticed my bike was overheating. I've never had this issue previously. I was only a few miles from home so I delt with it. When I arrived home, I noticed a coolant tube was off (image attached). I put it back on and tightened the ring. I then flushed the coolant, filled the radiator, and filled the reservoir to a bit over the low mark. When I rode next, I noticed coolant splashing out of the reservoir at higher RPMs (~12k+).

This issue only happens when in gear at higher RPMs. I have driven it a few miles at low RPM and there was no change in reservoir level. All it takes is one rip of the throttle and the reservoir will go from "low" mark to well over "high". During this throttle rip, the bike will also almost instantly overheat (~249F or 120C) before slowly cooling back down. Before the incident, its never experienced overheating issues.

Things I have tried or noticed so far:
  • Can't recreate issue when in neutral
  • When in neutral and revving, I can see small bubbles in reservoir
  • No coolant in oil or vice versa
  • No performance issues
  • Water pump works fine
  • Temperature sensor works fine
  • Fans work fine
  • Replaced radiator cap
  • After recreating issue, when bike is off, reservoir coolant slowly lowers back down
At first, I suspected it was a head gasket issue, however since there is no performance issues or mixing of oil/coolant, I think it is a low chance of it being the problem. I would love to do a leakdown test, however I lack the tools and the experience to do so (local shop does it for $360 but I'd like to avoid it if possible).

Thanks for reading this far. Please let me know if you have any ideas!

Bike: 2017 R6 Raven (I've heard the color matters)
I'd have to look at it. Guessing in the dark from my place though, stretched cylinder studs (slightly), a headgasket on the way out or a slightly warped head.

Edit; I see you got it fixed and the head gasket was going. Glad you got it fixed bud. I guess I should have read the entire thread before I posted.
 

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Didy you test or replace the cap?
 

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Discussion Starter · #35 ·
Hey everyone, the issue was resolved. As I mentioned, it was a slight leak in my head gasket which is why it was only happening at higher RPMs. I found a mechanic that did work on the side. He replaced the gasket, valve adjustment, spark plugs (I provided), oil & filter (I provided), and brake fluid for 1k even. Everything now runs perfectly. He also looked into an issue with my ABS light always staying on since I changed the tires. The two issues are DTC ID: 31 - Hydraulic unit assembly (defective ABS solenoid power supply circuit) and ETC ID 53 - Vehicle system power supply (voltage of ABS ECU power supply is low). I am not sure what these issues are but I am still able to ride it.

Thanks again for all of your help through this, I really appreciate it!!
(Don't ride when your motorcycle when it is overheating, even for a few miles. I learned the obvious lesson the hard way)
 

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Hey everyone, the issue was resolved. As I mentioned, it was a slight leak in my head gasket which is why it was only happening at higher RPMs. I found a mechanic that did work on the side. He replaced the gasket, valve adjustment, spark plugs (I provided), oil & filter (I provided), and brake fluid for 1k even. Everything now runs perfectly. He also looked into an issue with my ABS light always staying on since I changed the tires. The two issues are DTC ID: 31 - Hydraulic unit assembly (defective ABS solenoid power supply circuit) and ETC ID 53 - Vehicle system power supply (voltage of ABS ECU power supply is low). I am not sure what these issues are but I am still able to ride it.

Thanks again for all of your help through this, I really appreciate it!!
(Don't ride when your motorcycle when it is overheating, even for a few miles. I learned the obvious lesson the hard way)
How many volts on the battery? Those codes seem to relate to the battery voltage not being high enough to kick the abs solenoid.

Also, I hadn't read through the whole thread when I responded, so that's my bad. I did edit my post though.

Regardless, good luck with stuff and keep the rubber side down.
 

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Discussion Starter · #37 ·
How many volts on the battery? Those codes seem to relate to the battery voltage not being high enough to kick the abs solenoid.

Also, I hadn't read through the whole thread when I responded, so that's my bad. I did edit my post though.

Regardless, good luck with stuff and keep the rubber side down.
I have not been able to test it yet but from the way it cold starts I believe the battery is weak. I will replace it and hopefully it will resolve the issue.

No problem! Thanks, I appreciate it!
 
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