RF900 Overheating

[Macstar]

Having just bought this bike 10 days ago second hand I am having overheating problems. Low on cash and a student, I'm hoping to replace things myself... Maybe some of you gurus can offer some advice on what could be the cause? (please) Here are the symptoms:

First of all, the bike is fine when moving but in traffic it overheats and last night it actually shut down the engine (I guess there's a fail safe). Obvioulsy i wouldn't have kept going if I knew it was that hot as according to the temperature guage at the time it was in the middle and no where near the red zone. So I guess my temp guage is faulty?

Next: I read on-line that if you can see coolant leaking from the pump the seals are probably gone. Well there is some leakage but do I really need to replace the whole pump or just the seals?

It has lost no fluid (apart from minor spots out of the water pump), so I don't think there are any leaks elsewhere that could be causing the overheating.

Should I go for a new thermostat, radiator flush and pump seals and see if that works? Would that make the temperature guage operate correctly? Cause I guess the radiator cooling fans aren't going to switch on until it gets to at least half way on my faulty temperature guage right, which could be adding to the problem.

One other crazy thing happened: The engine shut down (turned off) as mentioned last night when it presumably overheated and I left the ignition on with the radiator cooling fans doing their thing. I put the bike on its stand and suddenly after about 4 minutes the engine re-started automotically. Unfortunately my bike was in gear though and it went flying off with no rider at the helm. My immaculate body work is now scratched and the gear shifter snapped off. Gutted! Has anyone ever heard of a bike automatically starting again - seems pretty crazy! True story though.

[98tls]

never heard of a bike self starting....whats the oil like ie any water in it..thinking head gasket but not sure.also wondering of the consequences of a thermostat not opening.

[MacD]

Well that sounds all very strange (unbelievable really)! The RFs generally run cold due to a low temperature thermostat (opens at 78 degrees C), which is about 1/3 of the way up on the temperature guage. Sitting in traffic my bike will heat up though and the fan comes on at around 2/3 reading on the guage.

I don't know of any thermal cutout or similar so I would suspect that you may have some other electrical problem which caused the engine to stop, and maybe also was responsible for the very odd restart?

Check the wiring loom where it runs through the frame on the right-hand side just behind the steering head. The loom can wear through here as it moves as you turn the bars. I've added extra tape around the loom to protect mine, maybe you have a short at this point?

If you start the bike with the coolant cap off you should be able to see the flow of coolant. The thermostat has about 5 drill holes in it so even a closed/stuck thermostat should let quite a reasonable flow past.

Anyhow, I'd check the electrics as much as the cooling system given the symptoms. Good luck!

[Macstar]

Yeah I was too scared to check for water in the oil incase you're right about the head gasket. It hasn't lost any fluid so I'm hoping that's sweet, but will check that tomorrow (bike was towed to a mate's place). The electrics could be a problem too I'll have a looksee there too thanks. I'm hoping that's not the case I know how fidgety and subsequently expensive electrical stuff can be. Thanks guys.

[JimO]

if the stand was down it should have stalled

[Macstar]

True! I know that feature does usually work on my bike. At the time it self started I had a steel u-lock passing through the rear disc rotor. When it took off on its own last night it actually broke the lock! I think if it weren't for that lock though the bike could have gone flying into some parked cars! The Rf's must have a fair amount of torque to smash a lock and take off on a bunny hop start...

[MacD]

Here's a live link to a copy of the RF900 service manual.

[DingDong]

The bike wont start without the clutch engaged and the stand up... you would have to have an elc fault in both these and the starter switch or starter motor as well, seems highly unlikely and this all sounds like bull-shit to me, come-on own up... it pissed you off and you threw it to the ground didnt ya.

If the bike is overheating, the coolant will come out the overflow... unless the pump is stuffed or the T/stats jammed restricting flow.

If it overheated to the point it cut out, sorry dude your bike is gonna cost ya plenty... I'm not aware of any failsafe on the RF engine

[DingDong]

True! I know that feature does usually work on my bike. At the time it self started I had a steel u-lock passing through the rear disc rotor. When it took off on its own last night it actually broke the lock! I think if it weren't for that lock though the bike could have gone flying into some parked cars! The Rf's must have a fair amount of torque to smash a lock and take off on a bunny hop start...

Now, you've done it!, the rotor would have broken before the U bolt
I dont believe this is a real post...

[Macstar]

Come on guys - I've got no reason to bull shit. I'm seriously devastated. I sold my prized SRX400 to get this bike and saved for over a year. Now this has happened and I'm out of cash and with no transportation at all (apart from the bus). I swear every detail is 100% as it happened. The ubolt lock was a $25 shitty one, not a proper disc lock one and so yeah it broke before the disc rotor. I've just signed up to this site so I don't know if people usually lie here when they post stuff, but that's not what I'm about. Anyway what good would it do me in terms of finding out what is wrong with my bike if I distorted the details??????? The bike started on its own with the keys in the ignition and the stand down. This was about 4 minutes after the engine stopped on its own. I left the key turned on so that the radiator cooling fan would keep going whilst the engine had stopped cause I thought it obviously needed it (like some European cars do after you turn off the engine and walk away, the fans keep going for a minute or two). It jumped about 1 metre and fell on its side. I was standing next to it and pulled the clutch in (BUT BY THIS STAGE THE STAND HAD FLICKED BACK UP CAUSE IT HAD MOVED FORWARD). I managed to lift the bike back up on my own and no the engine was not still going at this stage.

[DingDong]

Come on guys - I've got no reason to bull shit...

People dont usually b/s... but your story is just so unbelievable, OK I'll give the bene of the doubt.
But you must be the unluckest biker still breathing

[imdying]

First of all, the bike is fine when moving but in traffic it overheats and last night it actually shut down the engine (I guess there's a fail safe). Obvioulsy i wouldn't have kept going if I knew it was that hot as according to the temperature guage at the time it was in the middle and no where near the red zone. So I guess my temp guage is faulty?

Next: I read on-line that if you can see coolant leaking from the pump the seals are probably gone. Well there is some leakage but do I really need to replace the whole pump or just the seals?

It has lost no fluid (apart from minor spots out of the water pump), so I don't think there are any leaks elsewhere that could be causing the overheating.

Should I go for a new thermostat, radiator flush and pump seals and see if that works? Would that make the temperature guage operate correctly? Cause I guess the radiator cooling fans aren't going to switch on until it gets to at least half way on my faulty temperature guage right, which could be adding to the problem.

They're just playing with ya mate.

First things first, cooling system. What makes you think that it's overheating if the gauge is reading ok? Is it steaming/boiling or something quite obvious?

Nothing other than a wiring fault, or faulty temp sender would make the gauge read wrong. The fans probably turn on using the same sender as the gauge, it that sender is rooted, neither the fans nor the gauge will operate properly. Test that sender. Probably a procedure for it in an RF900 manual, but you can always dangle it in a pot of boiling water and see what the gauge reads (just jerry rig some longer wires..). You indicate that your fans do work (left the key on so they'd work), which indicates either the sender is ok, or the fans and gauge have seperate ones, you'll have to establish that for yourself as I have no idea on your model.

Where abouts is the leak on the waterpump? If your pump is knackered, that would account somewhat for any overheating. Find out what a new pump is worth. Perhaps Motu can shed some light on how much leakage is a problem (I'm assuming it's coming from the small hole at the base of the pump?). I'm guessing any leakage is indicative of a worn pump, and should probably be replaced ASAP?

Hope that gets you started, sorting the temp problem is probably a good start.

[FROSTY:Me]

That bike must have been accident damaged before methinks.
The only way this could happen is a short in the wiring loom

[Sensei]

Take it back to where you got it from & get Ya Money back !

[crazybigal]

dude you fell off! it happens.
i had a short in my wiring on my rf, the wires are quite thin and the outer casing is not that thick so it wore a hole and shorted. take the inner plastics off and trace the loom from the kill switch and the loom from the headlight back to the frame, check for a crimp or a worn patch.
as for starting on the stand with the clutch out never going to happen, you batt would have gone flat to start with as your headlight would have been on if you had left the ingnition on.

Having just bought this bike 10 days ago second hand I am having overheating problems. Low on cash and a student, I'm hoping to replace things myself... Maybe some of you gurus can offer some advice on what could be the cause? (please) Here are the symptoms:

First of all, the bike is fine when moving but in traffic it overheats and last night it actually shut down the engine (I guess there's a fail safe). Obvioulsy i wouldn't have kept going if I knew it was that hot as according to the temperature guage at the time it was in the middle and no where near the red zone. So I guess my temp guage is faulty?

Next: I read on-line that if you can see coolant leaking from the pump the seals are probably gone. Well there is some leakage but do I really need to replace the whole pump or just the seals?

It has lost no fluid (apart from minor spots out of the water pump), so I don't think there are any leaks elsewhere that could be causing the overheating.

Should I go for a new thermostat, radiator flush and pump seals and see if that works? Would that make the temperature guage operate correctly? Cause I guess the radiator cooling fans aren't going to switch on until it gets to at least half way on my faulty temperature guage right, which could be adding to the problem.

One other crazy thing happened: The engine shut down (turned off) as mentioned last night when it presumably overheated and I left the ignition on with the radiator cooling fans doing their thing. I put the bike on its stand and suddenly after about 4 minutes the engine re-started automotically. Unfortunately my bike was in gear though and it went flying off with no rider at the helm. My immaculate body work is now scratched and the gear shifter snapped off. Gutted! Has anyone ever heard of a bike automatically starting again - seems pretty crazy! True story though.