Overheating

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shipfner
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Overheating

Post by shipfner »

I had to cut my ride short last night when I discovered my crankcase breather hose was melting and falling off of the crankcase breather opening. I was about 2 hrs into the ride, and not sure how long the hose had been melted for before I noticed it. Checked the coolant level when I got home and it was low by at least 1/3 litre (poured that much coolant in and it's just at top of fins now). It's a 2013 KTM 250XCW that I bought slighlty used this Spring. I checked the coolant level before my first ride (only 4 rides on it since then) and it looked fine. Ambient temperature-wise, I'd say it was hot as f*&#@ last night, if not hotter.... but I've never seen anything like this with the hose melting. So, any thoughts on:
-Is it normal to have lost this much coolant in just 4 rides? I guess I should be checking and topping up coolant before every ride? (I'm also trying to stay off the clutch as much as possible).
-What kind of damage might I have done to the bike last night? Is there anything I should be doing now other than top up coolant and change oil?
-If I go with Evans coolant, do I need to change out the hoses or anything else in the coolant system, or just give it a good flush?

boland
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Re: Overheating

Post by boland »

Check your inner (large) clutch cover gasket for leakage in between the power valve and the exhaust flange. Seems to be a common issue. If it's leaking you could be losing coolant from there.
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cerealkiller
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Re: Overheating

Post by cerealkiller »

It seems possible you could have lost that much over 4 rides, but I would expect you to notice the amount of steam that would cause.

If you overheated a couple times on your first ride and didn't top up again, it would happen more easily the next time. However, losing that much coolant would cause quite a bit of steam. I suggest you check your coolant before every ride.
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Braap791
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Re: Overheating

Post by Braap791 »

I have had the pleasure of dealing with that inner clutch cover gasket this year on my 300 I would start there first if you fill it up and it starts ending up on the garage floor thats most likely your issue. To use Evans you need to drain the system completely. Drain it all out and than use compressed air and blow it out some more. The more water you get out of the cooling system the better it is with Evans. I would double triple check all your hose connections and re tighten them. Do an oil change and inspect for "seriously milky" oil I would probably tighten the hose clamps first than add new Evans and get it up to operating temp and ride it. Than let it cool down and check if the level has substancialy dropped this could be caused by a poopy head gasket and in the most severe of cases it would not hurt to do a top end and replace all the necessary gaskets for saftey.

shipfner
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Re: Overheating

Post by shipfner »

Thanks for the replies. I'll check the inside clutch gasket and the rad hose connections. After that, the plan is to put in the Slavens impeller and Evans coolant. Hopefully the damage isn't already done.
In terms of coolant loss, I did noitce some overflow/steam the first couple rides of the season then nothing since. Maybe the level got too low to boil over again.

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Re: Overheating

Post by trailguy »

If you have any plastic elbow/"T's", they restrict flow and can melt. Replace with silicone hosed that are one piece/molded. Made a big difference on my XCF 250. Also running Evans - the stuff is awesome, never loose a drop on the death rides. :smirk:

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Re: Overheating

Post by shipfner »

Just looking at it now, it looks like in a crash yesterday I may have bent the pipe in towards the bike, on the rider's right side, so that the coolant tube coming off the impeller is touching the pipe. Does that sound like a bent pipe? Can't imaging it's supposed to be touching that tube.
Timing-wise, I did notice the melted crankcase breather tube shortly after that crash.

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RJHenry
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Re: Overheating

Post by RJHenry »

I cannot comment on the melted hose, but I have only one suggestion for overheating - go for the fan! Impeller, Evans, etc. all increase the heat transfer to the rads - but only airflow actually takes heat away from your bike.

Trailtech has come out with a very well priced kit for KTMs and for Honda X models.
http://www.trailtech.net/electrical/dig ... it/732-fn1

The Husaberg comes with one stock, and I am always surprised how often it is running after tight sections. I have NEVER lost a drop of coolant.

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cycleworks
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Re: Overheating

Post by cycleworks »

Im not sure Evans coolant is the best answer for overheating... kind of just masking a problem, right? Just my two cents....
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Re: Overheating

Post by Bark »

I had the fan on my 530. It never lost a drop in 3 years.

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WRocks
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Re: Overheating

Post by WRocks »

Boiling coolant is not a bad thing, it takes a ton of energy to boil water and that all energy is being taken away from an over heated engine.

Take a pot of water at 20°C and put it on the stove (assume 5000W), it comes up to 100°C (at sea level) then boils and holds that temperature.
Thus the 5000W of energy input is all being used up by phase change from liquid to gas. Same thing happens in an engine, albeit it at a higher temperature since the system is pressurized.

Check for leaks, keep coolant topped up, add an overflow bottle and a fan if you think you need to.
I never ran a fan in my 300 and rode it like it was stolen with no issues, but had all the rest right.
I also swabbed my coolant to DexCool (orange), it has ~5°C higher boiling point than regular Green coolant.

For a 2T ensure your jetting is right, if it is set right it runs and cools better. There's lots of info on the forum about it (see my old posts on 300 jetting), so am not going there.

I have nothing bad to say about Evans, as I have never used it.
Have heard of the occasional melted impeller or hose from it though.
However, if you have a coolant leak riding in the wood, Evans doesn't run in the Creeks, but water does... :smirk:
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axel99
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Re: Overheating

Post by axel99 »

Check for leaks and fix any flow restrictions (kinked lines). Coolants that boil at higher temps are likely just masking a damaged cooling system or a setup problem. Boiling is a good thing, its a unmistakable sign your bike is too hot and need to let it cool down. Fans work but should not really be necessary on a properly setup 250 2T or 4T.

Best solution .... ride faster :D
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cycleworks
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Re: Overheating

Post by cycleworks »

axel99 wrote:Check for leaks and fix any flow restrictions (kinked lines). Coolants that boil at higher temps are likely just masking a damaged cooling system or a setup problem. Boiling is a good thing, its a unmistakable sign your bike is too hot and need to let it cool down. Fans work but should not really be necessary on a properly setup 250 2T or 4T.

Best solution .... ride faster :D
Thats kind of what I was getting at.... just not the faster part (hahaha)! Gotta be a better answer than "hiding" the problem....
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cedric
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Re: Overheating

Post by cedric »

I've seen a few posts on KTMTalk about bad rad caps that don't hold the pressure correctly, might be worth trying another cap.

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AJRJ
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Re: Overheating

Post by AJRJ »

I've bent the pipe far enough to put a very small nick in the hose that runs up out of the water pump. Might want to check that...

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