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Keep on riding while the bike is overheated?

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This last weekend at an enduro race there was a long heavy section with lots of climbing through loose rocks and large boulders.

On my practice run the bike overheated twice so i stopped and let it cool off a bit before starting it again each time.

But on race day on my 1st lap the bike overheated in the same section i stopped just a bit to let it cool off but people started to gain on me.

So on my 2nd and 3rd lap i didnt stop eventhough i could hear the rad coolant boiling over, and tried my best to use the clutch the least i could and to keep my pace up to finish that section, cause i knew that after it there was a wide open section were the bike would cool off.

My question is:

1) How long after you hear the hissing sound of the coolant boiling over can you keep on riding

without affecting your engine?

2) On my 2nd lap since i didnt have any coolant with me i poured some water from a water bootle i had nearby at the pits on the radiator to compensate for all the coolant that was lost.

Just guessing It was around 300 ml -500ml.

Would this ammount of reg. water affect the hoses?

Should i drain it and fill it up with coolant?

Thanks!

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If racing or riding areas where overheating is prone I would install a recovery bottle. The overflow line goes into the head of the bottle and into the cooling fluid reservoir. A secondary hole is a must so when cooling the overflown liquid finds its way back into the radiator. Similar to a car set up with little extra weight. A 600 to 700ml thick plastic bottle would do and best installed on the opposite side of the silencer. Tricky to make it stay there.

Another solution would be the KTM road, a ventilator.

Loosing 500ml of water is more than half those radiators have in there normally.

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Find out why it boils, do you put too much coolant in it? Dont what bike you have, but my ktm 300 puke if there is just 5 cc more then it like..

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It boiled because it was a long technical sections with 3 or 4 rocky hills with little traction.

So it boiled due to low speed riding + lots of clutching and tire spin.

Its a 200 xc-w. It rarely happens to me.... but this was a very dificult section at least for me.

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Had the same issues on my 450 exc, I added a recovery bottle when she boils over it catches what comes out about 10min after the boil over it sucks the fluid back into the radiator.

Edited by Txkiller

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What psi pressure cap are you using? Most KTM folks use at least a 1.6 bar cap, and some 4 stroke bikes taking up to a 2.2 bar cap. Might look into this along with the over flow catch bottle.

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all the above is good. but don't destroy your motor for a local race. If you are in the points lead for a national win go for it - if not stop.

Things to check.-

jetting- are you to lean.

Check idle- to low causes low coolant flow.

coolant- use engine ice or some ones quality coolant.

clean your rads. I'm very surprised how much dirt can get stuck deep in a rad. I soak them with simple green and rinse with a garden hose ( NO PRESSURE WASHERS you will bend the fins)

rad cap- if a few years old replace.

add a recovery tank.

gearing- if your using your clutch a lot may be you need lower gears.

Add a fan kit.

Edited by dave-g

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on my '10 300xc I run a 2.0 rad cap, upgraded billet water pump impellor, coolant tank and engine ice. Has taken care of any overheating issues I have had. I have a fan on it but it never turns on, and might just take it off and sell it.

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Thanks for all your responses.

The bike is fine. The overheat issue was because i was riding on a track beyond my skill level and i was spinning the tire too much.

I understand that the bike will start to boil way before it reaches temperatures so high that may damage the motor.

So for me boiling is just a warning sign to let the bike cool off or to keep on riding but to be careful cause you are reaching dangerous temps.

I want to understand just how much is too much. Just in case it happens to me again.

A cap that takes more preassure or engine ice, IMO would keep me from knowing that i am starting to overheat the bike.

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Thanks for all your responses.

The bike is fine. The overheat issue was because i was riding on a track beyond my skill level and i was spinning the tire too much.

I understand that the bike will start to boil way before it reaches temperatures so high that may damage the motor.

So for me boiling is just a warning sign to let the bike cool off or to keep on riding but to be careful cause you are reaching dangerous temps.

I want to understand just how much is too much. Just in case it happens to me again.

A cap that takes more preassure or engine ice, IMO would keep me from knowing that i am starting to overheat the bike.

Pornstar, you are on the right track. I ride a lot of technical trails in the mountains. Every bike will overheat, and you are right it is often because of a situation beyond your or my abilities and we abuse the clutch at low speeds. A couple things for you. You should be using water in your rad in Mexico. coolant is for areas that have a freezing issue. Water is also very efficient at transferring the heat both absorbing it then dissipating it compared to many coolants. Its free!

Never, ever put a higher pressure cap on a ktm. Just let it boil when it must and keep moving. The newer ktms have a weakness... the gasket at the front of the case on the waterpump assembly is very narrow and can blow out... the higher pressure cap only makes the problem worse.

If you are in a tight spot and you are boiling over AND you know the bike is fine (ie jetting etc) just keep on moving... (pick better lines :) )

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Best answer is to runs Evans or Zip Ty waterless coolant. It has a boiling point of somewere around 350 so you won't boil over. Better to keep the coolant in there with no "hot spots" from air bubbles from boiling. As long as you don't ride extended periods at over 250 you're not going to do damage.

I've run it for a few years now since I discovered it. Lifesaver on a 4T, piece of mind on the 2T.

http://www.evanscooling.com

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Thumbs up on the Evans coolant !! You do still overheat when you are in the tight stuff but you wont lose that precious coolant. Evans will not build up pressure due to its extreme boiling point.. This is a life saver on your gaskets and the coolant will stay where it belongs .... It isnt a cure for overheating but it is a great product..

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It boiled because it was a long technical sections with 3 or 4 rocky hills with little traction.

So it boiled due to low speed riding + lots of clutching and tire spin.

Its a 200 xc-w. It rarely happens to me.... but this was a very dificult section at least for me.

I personnaly would run the coolant/ mix that is manufacture reccomended you might check rather a radiator cap for a 250 or 300 has a higher bar than your 200. Raising the bar will equal higher boiling points.

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