KTM overheated - what do I need to consider?

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9/30/2020 5:57 AM
Edited Date/Time: 9/30/2020 7:37 AM

This past weekend at NHHA in Utah, there was an uphill rock canyon that became a conga line. Lots of high-rpm spinning-wheels on wet/oily rocks to get through the rocks and up & over the rock ledges. I'm a 49 year-old vet B rider on a '16 KTM 350 XCF. Never hard on the throttle. I'm more of a smooth, roll fast through corner kind of rider. I've never overheated any bike before. But this time I had lots of steam coming out, and the hydraulic clutch got a bit sloppy while in the rock canyon and for a short while once I got up to speed. When it would overheat, I would shut it off and give the bike and myself time to cool down, about 2-3 times. Also, this was on the first loop. Once I got up to speed and back into my race pace, the clutch felt fine. It was 50 miles to the finish.

Afterwards, I checked the coolant and it was 1-2 inches below the radiator, so like 3 inches below the neck of the fill opening. I will change the oil. Other than that, anything I need to be worried about? I have about 105 hours on the bike. I've never been hard on clutch plates, but is this one of those times I should consider changing it?

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9/30/2020 6:29 AM

I wouldn’t worry about it. Change oil and top up coolant.

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9/30/2020 7:57 AM

Im with tuna. There is little you can do to keep the bike from heating up in those situations, tighter cap will keep it from boiling over but it'll be just as hot or hotter.

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9/30/2020 8:04 AM

If you don’t have a radiator fan and you’re racing off-road, you need to get one. I would also recommend getting the IMS catch can that fits in the frame. It can hold probably a flask sized volume of coolant in the event of a boil over. I run a Boyesen Supercooler in conjunction with these other two items on my FX450, and have yet to lose any coolant, even when riding in 105+ temps.

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9/30/2020 1:20 PM

Second the radiator fan suggestion.

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10/1/2020 6:55 AM

Thanks everyone! If I'm going to keep running these races with the harder/slower enduro sections, then I'm definitely going to the fan route and mods that Csar Fe mentioned.

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10/2/2020 9:24 AM

CSAR FE wrote:

If you don’t have a radiator fan and you’re racing off-road, you need to get one. I would also recommend getting the IMS catch can that fits in the frame. It can hold probably a flask sized volume of coolant in the event of a boil over. I run a Boyesen Supercooler in conjunction with these other two items on my FX450, and have yet to lose any coolant, even when riding in 105+ temps.

Which battery do you use?
From what I heard, running a fan can flatten the battery, so I guess its a balance between the stator output, battery capacity and fan set point.
I know that the current gen of SXF XCF FC FX bikes have low stator output.

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KTM250SX YZ125 YZ85 PW80 ZX6 FZX700

10/2/2020 11:03 AM

I able to make it to the race this year. I coulda showed that congo line how to boogie on my 200xc :D

Glad to hear your engine isn't smoked!

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10' 200 XC-w
96' XR600r

10/2/2020 9:37 PM

CSAR FE wrote:

If you don’t have a radiator fan and you’re racing off-road, you need to get one. I would also recommend getting the IMS catch can that fits in the frame. It can hold probably a flask sized volume of coolant in the event of a boil over. I run a Boyesen Supercooler in conjunction with these other two items on my FX450, and have yet to lose any coolant, even when riding in 105+ temps.

YZed250 wrote:

Which battery do you use?
From what I heard, running a fan can flatten the battery, so I guess its a balance between the stator output, battery capacity and fan set point.
I know that the current gen of SXF XCF FC FX bikes have low stator output.

Stock battery. I've had no issues. I have the fan set to come on at 195 degrees, so it doesn't run all the time. I think Engine Ice starts to boil somewhere around 250, so that's plenty of room to catch the heat and cool the bike down before boil over.

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