Hey Guys,
Trying to track down a coolant mess on my 2008 SuperDukeR with under 17,000 miles.
I cleaned the engine case today looking for the leak.
Started the bike and got it hot e-nuf to run the fan at 7 bars.
Was going to ride it to get it hot but it is raining outside, so opened the garage door and ran it.
Could not find any leak from the engine case, hoses, overflow bottle or radiator and turned the engine off.
Floor was dry.
As I was sitting there for a few minutes thinking my next move, a small puddle formed on the floor.
It came from an over flow hose that ends in the side support for the battery, aimed directly at the exhaust.
I think the other end of the hose is connected to the overflow bottle, but is hard to see.
Am I over filling the over fill bottle?
Or is there more to it.
Have to say the fill bottle is hard to get a read on.
I did check the radiator cap rubber gasket for the typical crud.
Cheers, and hope all is well with all.
RichUK
2020-04-18 20:32:00 UTC
RichUK
2020-04-18 21:19:00 UTC
Maybe.. the bottle doesn't actually need much in it. I keep mine on the minimum level.
The idea is that it only uses the bottle if it needs to and then sucks it back as it cools down. If the level is moving much then you are either racing or you have air trapped between the cylinders, or have a head gasket leak as was the case with mine.
The idea is that it only uses the bottle if it needs to and then sucks it back as it cools down. If the level is moving much then you are either racing or you have air trapped between the cylinders, or have a head gasket leak as was the case with mine.
RichUK
2020-04-18 22:07:00 UTC
Thanks for the reply.
All good info.
How did you know about the bad head gasket?
What test did you use?
Compression leak down and pull the radiator cap off and look for bubbles in the coolant?
Bought this bike used and no record of how old the coolant is or what it is.
Was thinking of a coolant flush with new coolant and radiator cap for starts, but it would be nice to check for the bad head gasket first.
Had the head gasket go bad on my 93 SAAB 900 and it hydro locked, could not turn the engine over.
Pulled the spark plugs out to pump the coolant out. Glad there was not a car in the next parking spot because coolant shot out 10 feet.
Oppps...
All good info.
How did you know about the bad head gasket?
What test did you use?
Compression leak down and pull the radiator cap off and look for bubbles in the coolant?
Bought this bike used and no record of how old the coolant is or what it is.
Was thinking of a coolant flush with new coolant and radiator cap for starts, but it would be nice to check for the bad head gasket first.
Had the head gasket go bad on my 93 SAAB 900 and it hydro locked, could not turn the engine over.
Pulled the spark plugs out to pump the coolant out. Glad there was not a car in the next parking spot because coolant shot out 10 feet.
Oppps...
RichUK
2020-04-18 23:04:00 UTC
Flush it and burp it, you can search for the procedure. Its not hard, you just have to get the front wheel about 20" off the ground.
RichUK
2020-04-19 08:44:00 UTC
On mine the engine would not stay burped.
Once you have air trapped between the cylinder you start to get a lot of liquid movement in the coolant catch tank. Get the front wheel nice and high and then undo the top bleed bolt on the water pump and allow coolant to flow for a few seconds to clear any air.
Mine was a very small leak on the rear cylinder. It would first put combustion gas between the cylinders, which is then trapped there and can cause a hot spot. Then when that was full it would go into the radiator, all the time this is happening it expels coolant into the catch tank. It also defeats the pull back mechanic as the radiator will remain slightly pressurised even when cold. Eventually enough coolant is expelled to drop the radiator level about 2 inch from the filler, and that point it was stable. The coolant vent hose always looked wet after a ride and one day I actually saw bubbles rising up through that overflow tank.
Eventually I accepted it had to be a head gasket so I tooled up to do the job. I started the strip down and once I'd got to the plugs I did a leak down test whilst watching the coolant level at the filler, which I'd first topped up.
BTW - The leak down test was just a means to put pressure in the cylinders and not to actually test the leakage. This head gasket leak was way too small to test for like that. The front cylinder took 80 psi for a few minutes with no change.The Rear only needed 60 psi for about 30 secs before I could see the coolant level rising.
I changed just the rear head gasket and it sorted it. The level in that tank doesn't seem to move at all now, and the radiator stays full to the top.
If I were to buy another 990 I would check the rad level straight away now.
Yours will likely be that it just hasn't been burped properly, or it could even be that your radiator cap is faulty so change that if it continues doing it after burping it.
Everyone told me that these engine are not prone to head gasket failures, even my local KTM dealer did... so I guess I was just unlucky, but if burping doesn't sort it (or the rad cap) then IMHO it's time to test for a small head gasket leak.
Once you have air trapped between the cylinder you start to get a lot of liquid movement in the coolant catch tank. Get the front wheel nice and high and then undo the top bleed bolt on the water pump and allow coolant to flow for a few seconds to clear any air.
Mine was a very small leak on the rear cylinder. It would first put combustion gas between the cylinders, which is then trapped there and can cause a hot spot. Then when that was full it would go into the radiator, all the time this is happening it expels coolant into the catch tank. It also defeats the pull back mechanic as the radiator will remain slightly pressurised even when cold. Eventually enough coolant is expelled to drop the radiator level about 2 inch from the filler, and that point it was stable. The coolant vent hose always looked wet after a ride and one day I actually saw bubbles rising up through that overflow tank.
Eventually I accepted it had to be a head gasket so I tooled up to do the job. I started the strip down and once I'd got to the plugs I did a leak down test whilst watching the coolant level at the filler, which I'd first topped up.
BTW - The leak down test was just a means to put pressure in the cylinders and not to actually test the leakage. This head gasket leak was way too small to test for like that. The front cylinder took 80 psi for a few minutes with no change.The Rear only needed 60 psi for about 30 secs before I could see the coolant level rising.
I changed just the rear head gasket and it sorted it. The level in that tank doesn't seem to move at all now, and the radiator stays full to the top.
If I were to buy another 990 I would check the rad level straight away now.
Yours will likely be that it just hasn't been burped properly, or it could even be that your radiator cap is faulty so change that if it continues doing it after burping it.
Everyone told me that these engine are not prone to head gasket failures, even my local KTM dealer did... so I guess I was just unlucky, but if burping doesn't sort it (or the rad cap) then IMHO it's time to test for a small head gasket leak.