[TwistedMister]

could be the issue, run a gallon M12 through it see what happens

 

[Browniee]

could be the issue, run a gallon M12 through it see what happens

I’ve done that , gives me the same results

 

[Browniee]

I just took the thermostat out and took the radiator off and flushed it real good , when I’m adding fluid as soon as I top it off and crank the bike with the lid off it just starts pouring over , is this normal?

 

[BillV]

"if the bikes completley cold , the gause reads 80ish before i even try to crank it"
Unless it doesn't get below 80 °F where you live, that doesn't sound right. My K6 displays "---" below 68 °F. I'd expect yours to do the same.

I've never done this on a bike but would expect the bike to run normally with the radiator cap off, i.e. without coolant shooting out. That sounds like a blockage. I've done it many times on cars.

 

[Browniee]

"if the bikes completley cold , the gause reads 80ish before i even try to crank it"
Unless it doesn't get below 80 °F where you live, that doesn't sound right. My K6 displays "---" below 68 °F. I'd expect yours to do the same.

It’s about 85 degrees out in the day time

 

[BillV]

How cold does it get overnight?

 

[Browniee]

How cold does it get overnight?

Right now the forecast says 65 but usually around 55

 

[jeremyr62]

There's no point running it with the thermostat out. Thermostats rarely fail. They act to restrict the flow even when fully open. You need the restriction so the coolant is retained in the radiator so it can cooled. If you take the thermostat out the hot coolant wizzes through the rad and doesn't get chance to transfer its heat to the air.

 

[Skilla]

With high temps and high RPMs, the coolant pressure can exceed 1 bar / 14psi, seen it go past 1.5bar / 20psi

Just a few questions,
When the Cap blew off, did it bend/break the cap where it latches to the radiator? ie. deformed the cap or radiator?(pointing to massive increase in pressure)
Did you replace the cap with the correct OEM part?

If you have a temperature gun, does the temperature that is displayed on cluster match the actual temperature where the sensor screws into the engine?

When the head gasket was replaced, do you have photos perhaps of what the sealing areas looked like on the block and head?
Photos of the head gasket that was removed to see what the damage was ?
as if the damage was severe on the gasket, there is a really good chance that the sealing surface got damaged and you mentioned only the head was cut.

Tests I would do in this instance:
Leak down and Compression tests
Coolant system pressure and Radiator cap pressure test ( just to be safe / curious)

because the bike was "tuned for MR12" & "it had this problem since the beginning" statements, I would start testing elsewhere than the coolant system, and one of the above mentioned tests should point to the failed part, and guessing it will be gasket again.
unless the bike has a dual map setup, with it being tuned for a specific fuel, means that there is a much higher chance of it running very lean or detonating when running pump fuel, and by increasing the compression with a thinner gasket just makes it worse.

 

[TwistedMister]

I’ve done that , gives me the same results

then that tells you an enormous amount right there, dood lied when he sold you the bike..

also a working radiator cap will not blow when secured properly, they are self bleeding at a specific pressure deemed catastrophic or too much pressure and or temp, tempo and pressure go hand in hand..why they have a spring under the seal, if enough pressure builds up too high the spring contracts and pressurized coolant flows out the radiator into the reservoir, once the pressure in the reservoir reaches a certain point it then spews out the bottle vent hose..

the cap should never fly off, not after its secured properly, we should have pics of everything, something is off here...

seems like a clogged radiator overflow hose, or clogged res bottle overflow hose..

the function being the overflow system is engineered to vent the hottest of situations, the fact your cap is blowing off means something, wrong cap perhaps? radiator caps have a pressure value in PSI, not all radiator caps are the same even if it fits, it may be that your cap has too strong of a spring in it? not allowing the pressure to vent at the right time before the fan is activated and the pressure builds up so much it blows the cap?

you can burst a radiator installing the wrong cap

get a proper new cap for giggles, check those hoses again, is the hose from radiator to bottle getting kinked or blocked? same for bottle vent hose..

 

[what?]

did you buy this bike used or did you do all the mods? if used check the mods like the pair valve, maybe someone removed it and didn't block it off? dunno much bout the L9's pair but if it works the same way as previous gens then if you remove it without blocking off you will get alot of fresh air going into the cylinders..

Excuse me Twsted, but this statement about the PAIR valve leads me to believe you don't really know How the PAIR system works. Period. It CAN'T get into the cylinders when the Pair venturri is solely in the exhaust port! LOL Most people don't really understand how it works and why. Or the fact if you simply leave the pair valve in and hook it straight to the crankcase breather tube- it's a dyno proven 2-6HP gain on the dyno. Proven.
air Into the exhaust? maybe? anything about the pair system itself can NOT make the cylinder run lean. It can put some air into the exhaust though- falslely and slightly altering the a/f ratio. To take that false reading away a good dyno tuner will plug the system so that NO extra air makes it to the sniffer that measures the a/f ration in the tail pipe.
The Cumbustion chamber itself- and the plugs never see any air brought in by the PAIR valve. Only the exhaust- it's ONLY to help with emissions on idle and low speeds.

 

[what?]

Is it the reservoir cap, or the radiator cap blowing off?

 

[Browniee]

There's no point running it with the thermostat out. Thermostats rarely fail. They act to restrict the flow even when fully open. You need the restriction so the coolant is retained in the radiator so it can cooled. If you take the thermostat out the hot coolant wizzes through the rad and doesn't get chance to transfer its heat to the air.

i was only taking the thermostat out to diagnose the problem

 

[Browniee]

With high temps and high RPMs, the coolant pressure can exceed 1 bar / 14psi, seen it go past 1.5bar / 20psi

Just a few questions,
When the Cap blew off, did it bend/break the cap where it latches to the radiator? ie. deformed the cap or radiator?(pointing to massive increase in pressure)
Did you replace the cap with the correct OEM part?

If you have a temperature gun, does the temperature that is displayed on cluster match the actual temperature where the sensor screws into the engine?

When the head gasket was replaced, do you have photos perhaps of what the sealing areas looked like on the block and head?
Photos of the head gasket that was removed to see what the damage was ?
as if the damage was severe on the gasket, there is a really good chance that the sealing surface got damaged and you mentioned only the head was cut.

Tests I would do in this instance:
Leak down and Compression tests
Coolant system pressure and Radiator cap pressure test ( just to be safe / curious)

because the bike was "tuned for MR12" & "it had this problem since the beginning" statements, I would start testing elsewhere than the coolant system, and one of the above mentioned tests should point to the failed part, and guessing it will be gasket again.
unless the bike has a dual map setup, with it being tuned for a specific fuel, means that there is a much higher chance of it running very lean or detonating when running pump fuel, and by increasing the compression with a thinner gasket just makes it worse.

im not 100% sure on any of the tuning , once i was told it was tuned for mr12 and 87 and now im being told only mr12 and it was the rsevoir cap that flew off not the radiator cap.

 

[Browniee]

then that tells you an enormous amount right there, dood lied when he sold you the bike..

also a working radiator cap will not blow when secured properly, they are self bleeding at a specific pressure deemed catastrophic or too much pressure and or temp, tempo and pressure go hand in hand..why they have a spring under the seal, if enough pressure builds up too high the spring contracts and pressurized coolant flows out the radiator into the reservoir, once the pressure in the reservoir reaches a certain point it then spews out the bottle vent hose..

the cap should never fly off, not after its secured properly, we should have pics of everything, something is off here...

seems like a clogged radiator overflow hose, or clogged res bottle overflow hose..

the function being the overflow system is engineered to vent the hottest of situations, the fact your cap is blowing off means something, wrong cap perhaps? radiator caps have a pressure value in PSI, not all radiator caps are the same even if it fits, it may be that your cap has too strong of a spring in it? not allowing the pressure to vent at the right time before the fan is activated and the pressure builds up so much it blows the cap?

you can burst a radiator installing the wrong cap

get a proper new cap for giggles, check those hoses again, is the hose from radiator to bottle getting kinked or blocked? same for bottle vent hose..

it wasnt the radiator cap that was flying off , it was the resevoir cap that kept coming out, yesterday i tore it down for the thoussandth time , i flushed the radiator with water and checked all the lines , all the big ones were good and most the small ones , i found that the overflow tube had what seemed to be a stick shoved up in it , i got it completley out and refilled with fluid and took the thermostat out, i couldnt test it till today when i got fluid and i took it for a 3-4 mile ride , coolant was coming out of the overflow hose prettty good when i got to going good , my whole boot was soaked with fluid , the bike rode at 200-210 and when i slowed down to turn it would creep to 230 then when i got moving again it would be back at 200-210 , this is really bugging me and i wish i can figure it out soon..

 

[TwistedMister]

Excuse me Twsted, but this statement about the PAIR valve leads me to believe you don't really know How the PAIR system works. Period. It CAN'T get into the cylinders when the Pair venturri is solely in the exhaust port! LOL Most people don't really understand how it works and why. Or the fact if you simply leave the pair valve in and hook it straight to the crankcase breather tube- it's a dyno proven 2-6HP gain on the dyno. Proven.
air Into the exhaust? maybe? anything about the pair system itself can NOT make the cylinder run lean. It can put some air into the exhaust though- falslely and slightly altering the a/f ratio. To take that false reading away a good dyno tuner will plug the system so that NO extra air makes it to the sniffer that measures the a/f ration in the tail pipe.
The Cumbustion chamber itself- and the plugs never see any air brought in by the PAIR valve. Only the exhaust- it's ONLY to help with emissions on idle and low speeds.

guess I should have clarified, oops... surely I know it does not alter the A/F on the intake side, I've seen plugs look lean without plates bolted on..

 

[TwistedMister]

it wasnt the radiator cap that was flying off , it was the resevoir cap that kept coming out, yesterday i tore it down for the thoussandth time , i flushed the radiator with water and checked all the lines , all the big ones were good and most the small ones , i found that the overflow tube had what seemed to be a stick shoved up in it , i got it completley out and refilled with fluid and took the thermostat out, i couldnt test it till today when i got fluid and i took it for a 3-4 mile ride , coolant was coming out of the overflow hose prettty good when i got to going good , my whole boot was soaked with fluid , the bike rode at 200-210 and when i slowed down to turn it would creep to 230 then when i got moving again it would be back at 200-210 , this is really bugging me and i wish i can figure it out soon..

a stick shoved up the outlet tube can create this issue, it needs to breathe

 

[Skilla]

....i found that the overflow tube had what seemed to be a stick shoved up in it ....

that will cause the reservoir cap blowing off issue as twisted stated,

.....i got it completley out and refilled with fluid and took the thermostat out, i couldnt test it till today when i got fluid and i took it for a 3-4 mile ride , coolant was coming out of the overflow hose prettty good when i got to going good , my whole boot was soaked with fluid....

If you overfilled the reservoir bottle it will do this on the first ride, as when it gets really hot it will "purge" water from radiator into the reservoir bottle, and with it being over filled, will expel water until a balance is maintained, the reservoir acts like a water expansion bottle

the bike rode at 200-210 and when i slowed down to turn it would creep to 230 then when i got moving again it would be back at 200-210 , this is really bugging me and i wish i can figure it out soon..

was the test ride with the thermostat installed or without?

I would suggest to go and get an original radiator cap from Suzuki and the overflowing should stop.

Had a K7 that kept overflowing when it started getting hot, replaced the radiator cap twice with aftermarket ones with te correct pressure rating, but still overflowed until I got an original one from Suzuki.

If it still overflows once you replace the radiator cap, then the engine is introducing additional pressure into the system that can only come from a bad head gasket

 

[Browniee]

that will cause the reservoir cap blowing off issue as twisted stated,


If you overfilled the reservoir bottle it will do this on the first ride, as when it gets really hot it will "purge" water from radiator into the reservoir bottle, and with it being over filled, will expel water until a balance is maintained, the reservoir acts like a water expansion bottle


was the test ride with the thermostat installed or without?

I would suggest to go and get an original radiator cap from Suzuki and the overflowing should stop.

Had a K7 that kept overflowing when it started getting hot, replaced the radiator cap twice with aftermarket ones with te correct pressure rating, but still overflowed until I got an original one from Suzuki.

If it still overflows once you replace the radiator cap, then the engine is introducing additional pressure into the system that can only come from a bad head gasket

it has all original caps on it , could it have anything to do with me having the head cut and running a thinner head gasket? maybe i took too much off and should run stock gasket?

 

[TwistedMister]

If you overfilled the reservoir bottle it will do this on the first ride, as when it gets really hot it will "purge" water from radiator into the reservoir bottle, and with it being over filled, will expel water until a balance is maintained, the reservoir acts like a water expansion bottle

what I like about these looped cooling systems, a lot of folks have issues with em but you just keep filling that reservoir bottle and it will keep sucking it in till it's perfectly full, fill it to much and like you say it spits out what it don't want then its dead nut perfect....

these systems have been around since what late 70's early 80's? soa lot of you guys don,t know how to the old school cars operated cooling wise, the hose coming out the radiator just went to atmosphere, before that they didn't have pressurized caps so it was real tricky when things beg and to overheat, of course those engine didn't create near the heat the 60's models do but enough to blow radiators open, yup

the 1939 buick was the first vehicle to utilize the radiator cap as we know it, so before that...

funny how for around 3 decades they finally realized "hey, all we need to do is run the overflow hose into a reservoir bottle and run a hose out the top of the reservoir bottle to atmosphere and whallah! no more losing coolant to the ground... which BTW was bad, back in the day animals would drink the coolant after it cooled and became poisoned so in reality the reservoir bottle has saved many a cats.. and typically it as the car owners cat, park in the driveway, a little spills out, crazy cat comes along and laps it up.. no more cat