Ktm 150 sx 2018 vibration

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6/23/2018 3:48 AM

Hi,
I bought a Ktm 150 a few weeks ago, went and ran it in and everything and the thing vibrates like mad. I get that there will be some vibration with the bike but it’s bike holding onto a running generator makes your hands tingle and this is through the bars, seat and pegs. I’ve checked the all the engine mounts and swing arm to make sure that’s all tight. The only other thing I can think of is the crank is out of balance.

If anyone has any advice on what it could be or if anyone has a Ktm 150 and this is normal for them please let me know.

Cheers
Marcus

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6/23/2018 3:57 AM

Yeah next thing to look at is the crank. If youre really that concerned about the vibration, take a look. Last thing you need is it to send a rod through the cases. Its hard for anyone online to say if its normal if we cant actually feel it. 2 strokes do vibrate a lot though

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6/23/2018 4:18 AM

That’s the only other thing I can think of. The bikes only 2 weeks old with 3.2h on it. I get that 2 strokes vibrate abit ive riden them for a few years now but this is next level vibration. Il keep looking into it cheers kb228 ??

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6/23/2018 4:44 AM

Wow 3.2 hours? Shit id take it to the dealer and have them look it over. Dont care what bike it is there shouldnt be any crank issues when its brand new. Hell they might just tell you its normal.

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6/23/2018 9:57 AM

I have an '18 150sx and the vibration is very little. I had a '17 300xc two stroke with the counter balancer and I would say my 150 vibrates about the same or less. A friend of mine had a new '18 150sx he bought at the same time as mine and it vibrated way more than mine. I rode it and thought to myself that this thing vibrates like a 250 2t without a counter balancer. As an mx engine builder in a past life my first thought was that the crank probably has a runout of at least .005" for it to vibrate that bad. His bike was brand new with .5 hrs on it. I'm just glad my 150 crank is true and there is very little vibration. It would be a tough sell to get the dealership to have KTM get involved as the bike runs except for the vibration. Cranks should be less than .0015" total runout. I have seen new OEM cranks come at over .003-.004" and some were horrible. On a 125-150 this will be a huge annoyance. On a 250-500 it's unbearable and will rattle your teeth. Lol. I true all of by crankshafts when new and bring them to .0005" or less. The difference is amazing. I have actually refused to take delivery of a new YZ250 at the dealership because it vibrated like crazy and I knew the crank wasn't true. The salesman was annoyed as I made them uncrate another new bike. He was surprised as the new one had zero vibration compared to the other one. Go figure. Lol. Good luck!

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6/23/2018 9:51 PM

Check all the bolts holding the engine into the frame.

Check the headstay bolts(upper engine mounts)

Check swingarm nut.

I have a constant problem of mine coming loose. Use proper torque specs and loctite. I’ve actually now had to safety wire my engine bolts because they come loose often.
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