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2018 KXF450 loses power after few laps

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My new 2018 KXF450 loses power after a few laps (on a sandy mx track) I logged about 6 hrs on it so far.

What is the most probable cause for this? Theoretically it can be anything from a defective sensor to..?? but it's a brand new bike!

Any suggestions are welcome

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So, can you give some more details? Does the power come back when the engine is colder? As in, before your few laps are completed?

Details will really help out with this

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8 hours ago, Ryankx250 said:

So, can you give some more details? Does the power come back when the engine is colder? As in, before your few laps are completed?

Details will really help out with this

Yes when I get back on the track after bike has cooled down it is good again, for about 10mins. Also depends on the track, in loam wet sand it is more noticeable then on hardpack like conditions, seems when bike must pull harder power drops sooner

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I am convinced motor is getting a bit too hot. Mapping is adjusted for more fuel. Could OEM exhaust be too restrictive maybe?

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You boiling the fuel?


X2

Insulate the bottom of the tank with foil tape/blanket

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Really?? Did you experience this first hand? Anyway I will give it a try as this would be an easy/cheap fix.

Can I rule out the OEM exhaust front pipe/muffler as being restrictive, as I only see a few "small wings" in the perforated core to restrict noise?

Thanks for your suggestions!

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8 hours ago, frankdecrosser said:

Really?? Did you experience this first hand? Anyway I will give it a try as this would be an easy/cheap fix.

Can I rule out the OEM exhaust front pipe/muffler as being restrictive, as I only see a few "small wings" in the perforated core to restrict noise?

Thanks for your suggestions!

Yes you can rule out the exhaust , because its the same exhaust you have before you loose power (you loose power after  few laps, same pipe all the time)

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23 hours ago, skorpan777 said:

Yes you can rule out the exhaust , because its the same exhaust you have before you loose power (you loose power after  few laps, same pipe all the time)

Valid comment, I was thinking in the same direction, but also wondering if -in case muffler is somewhat restrictive- engine heat could gradually build up to a degree that it becomes noticable. I hate to waste money on an aftermarket exhaust and therefore I covered bottom of tank with reflective tape first as advised.

Will let you know if this works.

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Maby your clutch start slipping if you are a clutch abuser, especally if its a sand track.

Try buy a very good oil , like Castrol Racing 5W-40 or a MAXIMA oil (be sure its 100% synthetic sometimes "fully synthetic" is not that, sometimes its not the same, its just marketing 101)

Edited by skorpan777

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Really?? Did you experience this first hand? Anyway I will give it a try as this would be an easy/cheap fix.


I ride off-road only but I can hear the bubbling when I kill it in tight spots.

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Tried reflective foil under the tank this weekend in fairly hot ambient temps, and your solution seems to work, I noticed no loss of power. 

Although two tracks I went were not ultra loam sand, difference is definately noticable, best tip I had on TT so far, thanks so much!

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I sure think it does, tried some simple very thin aluminium tape first, but this didn't hold very well, probably due to gasoline vapours because I remember tank stickers on Suzuki's in the early 80's coming loose because of this.

Installed thicker heat shielding from a specialized firm now, but it does not seem to be a big improvement over the alu tape.

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3 hours ago, frankdecrosser said:

I sure think it does, tried some simple very thin aluminium tape first, but this didn't hold very well, probably due to gasoline vapours because I remember tank stickers on Suzuki's in the early 80's coming loose because of this.

Installed thicker heat shielding from a specialized firm now, but it does not seem to be a big improvement over the alu tape.

Ok good to know,.

Cheers 

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