2021 FC 350 timing chain noise on starts

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2/18/2021 5:19 PM

Hello everyone, i just bought a new 2021 Husky FC 350. The thing is that on cold start it makes a loud clattering noise for aboutt 3-5 seconds, and on hot starts for a out 1-2 seconds. The bike is fully stock and only has 3 hours.

I took it to the dealership and they say its normal... BUT I dont think so, ive had 2017-18-19 and 20 Fc350 and none of those made the noise.

Its like the timing chain tensioner is loose until it gets oíl pressure.

What do you think?

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2/18/2021 5:36 PM

Normal. The cam chain tensioner is hydraulic and needs to build pressure.

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2/18/2021 6:30 PM

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2/19/2021 1:38 PM

wildcard wrote:

Hello everyone, i just bought a new 2021 Husky FC 350. The thing is that on cold start it makes a loud clattering noise for ...more

There is valve 'lash' till you build pressure and the cam chain tensioner starts to keep pressure on the chain. It's pretty normal on these bikes, as long as it only lasts a few seconds.

Definitely continue with 50W oil, as recommended in the manual.

It can be fixed with a dirt tricks or manual tensioner. The advantage of the dirt trick is that it's automatic, although the manual tensioners don't need adjusting that often any way.

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KTM250SX YZ125 YZ85 PW80 ZX6 FZX700

2/21/2021 6:56 AM

I had the same issue. The dealer put a new tensioner in under warranty after the first ride. I rode it the second time with the new tensioner and it still did it. Not as severe, but still there. My dealer told me to switch to motorex oil and see what happens. As stupid as it sounds, the oil fixed it. Zero chatter now.

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2/22/2021 9:04 AM

There was another thread on this last year. This is common to both the 250 and 350 (same engine/tensioner).

https://www.vitalmx.com/forums/Tech-Help-Race-Shop,42/New-2020-KTM-350sxf-Loud-Engine-Noise,1370573

You'll see in that thread I installed the Nihilo gen-2 manual tensioner. I would say this tensioner not only stops the chain slop noise but is also a performance improvement. The bike seems to rev freer/faster, especially on the top end.

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