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Knock under load

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This is my first DR-Z400S and right out of box hear pretty loud "Knock" only under load. What is it with the DR-Z400 motor that causes it?

I've owned 20 different bikes over 30 yrs and none of them ever did this.

I love the bike, but the knock just bothers me. Some guys say get used it or wear earplugs and that's cool, but I want to hear all the reasons and opinions so I can decipher the best answer for me. It is not lifters ticking, this is a decent knock sound under load for every rev that it fires. All the things inside are properly tightened down and loctited per the forum's instructions, and she still has the sound. I will live with the noise, but what the hell causes it??? It is not spark knock from poor gas. I know this sound and it is not this.

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It is piston slap , the only way to stop it is to not lug the motor and always be in the right rev range for the gear you are in . Or fit a big bore and it will go away , greg

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ok, if it is piston slap, is this a somewhat common problem for suzuki drz400 motors right out of the factory?

I guess since it is under warranty the dealer should fix it right?

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These aru just noisy motors. Durable but noisy. See if you can find somebody with one close to you and compare them while running.

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ok, if it is piston slap, is this a somewhat common problem for suzuki drz400 motors right out of the factory?

I guess since it is under warranty the dealer should fix it right?

Nothing to fix but the rider and how that rider uses the motorcycle.

It's really pretty simple. It's not a tractor, . Don’t lug the motor.. the higher gearing of the S makes that a little harder to do then an E.

Bigger riders, riders that are not used to slipping the clutch under load, riders that are not used to a smaller sized single cylinder thumper that was built to rev more than other older thumpers, will all tend to lug the motor unless instructed or self taught not to.

Again… Don’t lug the motor

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Im with the dont lug it crowd, if I babied my around I would get paranoid and think it was something terrible..run it up and keep revs high and noise all but goes away. dont read the manual on shift points, and if you have not done 3x3 and jetting, its well worth the $100 bucks for the added power and better response.

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My big bore DRZ is definitely quieter than a stock DRZ top end. Dunno if its the forged piston holding better tolerances than the OEM cast unit or what. Just an observation

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ok, thanks guys! I aint gonna worry about it anymore. And I definetely aint lugging it! I have just turned 600 miles on her today, and I am keeping her in the high rev area. Maybe I'm just a bit OCD, but I think the noise may be getting quieter as I rev the pee out of it.

At least that way I hear loud exhaust noise and it drowns out any other up front noise!

The DR-Z400 is a cool looking bike and a blast to ride.

Appreciate all the info.......

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I've got a 2011s and I was always paranoid about it. 3k on the clock now, still noisy, but I just don't worry about it.

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Thanks flying junk! I feel better now knowing your 2011 has same thing.

(Not to wish something bad on your machine)

If it was just me , I'd be bumming, but it is what it is, so enjoy the riding.

I suppose if this is the worst thing in our life, we're damn lucky!!

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Mine does it too. '07 bone stock 400S. I never bothered me, but I've had a couple quads that sounded like this too, and never had issues with them either.

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