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Strange Noise

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Need a little help. I have a noise when in gear under throttle. It is so hard to pin point where it is coming from. Did a search on engine noise but most point to the cam chain. The bike is a 2012 with 5k miles on it and in great condition. I just bought it a month ago and want to find out if this sound is just something normal with the DRZ's. This is the first dirt bike I have had in over 30 years, been drag racing bikes for the last 20 years and I just might not used to the sound of a thumper. Best scenario to describe when I hear this sound is when I am up to a constant speed in higher gears such as 3rd-4th or 5th just cruising at about zero to a quarter throttle. When I apply slight throttle I hear a knocking kind of a sound from the lower end. Its not a clutch or clutch basket sound, bad bearing sound (oil spotless),piston slap sound or valve tapping sound, it sounds more like backlash if you want it to call it that in the tranny area. Under higher RPM's (half throttle or more) smooth as can be. Just would like to hear from everyone on this issue for a little help. Just might be my racing ear reaching on noises when riding a thumper. Thanks in advance...

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Under idle and in neutral low to high rpms there isnt any noise. Again only rolling in gear using light throttle in higher gears.

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Yeah, don't lug the engine.

 

Something else you might want to check is chain slack. Mine would make a noise while accelerating when the chain was too loose. Adjusted it to the correct slack and the noise went away. It was pretty easy to tell it was on the left side though.

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Under idle and in neutral low to high rpms there isnt any noise. Again only rolling in gear using light throttle in higher gears.

Under the operating conditions you describe here, I would have to agree with Wisconsinite about your chain being a little slack.

If you tap on the chain roller that's on the frame, I'm sure you will notice the sound is very similar to the one you hear while riding.

Hopefully you will be relieved with such an easy fix.

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Thanks for all the info but the chain is right within spec.This sound is a: I am coastong about 30 along a secondary street in 4th st low rpms and a start to roll on the throttle I get that knocking sound. Not like a chain slap would make. As you are giving it light throttle the engine seems clunky until the rpms come up. It seems as if the bike is not under a descent load (torque or throttle) the sound is there.

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sorry about the spelling this voice text is terrible at times

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I understand...but in slow to moderate traffic and between stop sighns in neighborhoods what else is the choice. Just guess I am going to have to learn to accept that chugging knock sound. Going to try to go to a 50 weight oil And sEe if that quiets the tranny a little. I swear that's where all the sound is coming from just the backlash in the gears...but what do I know I'm just guessing at this

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Thanks for all the info but the chain is right within spec.This sound is a: I am coastong about 30 along a secondary street in 4th st low rpms and a start to roll on the throttle I get that knocking sound. Not like a chain slap would make. As you are giving it light throttle the engine seems clunky until the rpms come up. It seems as if the bike is not under a descent load (torque or throttle) the sound is there.

does it sound like a hollow repetitive knock knock knock as you gain rpm under load, if so normal IMO.

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I understand...but in slow to moderate traffic and between stop sighns in neighborhoods what else is the choice. Just guess I am going to have to learn to accept that chugging knock sound. Going to try to go to a 50 weight oil And sEe if that quiets the tranny a little. I swear that's where all the sound is coming from just the backlash in the gears...but what do I know I'm just guessing at this

 

 

the more hooked your front sprocket is, the worse a chain inspired noise will be. give it a look, it may be worn out. 

 

if you're certain it's not that, it could be the (completely normal) chain slapping against the swing arm chain slider. even with proper tension it does this when the engine is run in slower rpm's with higher gears. i prefer to keep a higher rpm (but not screaming of course) i na lower gear to prevent chain slap while cruising through lower speed areas. 

 

have you done the loctite fixes yet ? 

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I understand...but in slow to moderate traffic and between stop sighns in neighborhoods what else is the choice. Just guess I am going to have to learn to accept that chugging knock sound. Going to try to go to a 50 weight oil And sEe if that quiets the tranny a little. I swear that's where all the sound is coming from just the backlash in the gears...but what do I know I'm just guessing at this

you could downshift? get a nice sound too...
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Going to do the loctite fixes and check everything out. thanks to everyone for all the info. sounds more and more like this is a common sound. Front sprocket is like new put on a brand new o ring chain when I installed a 47 tooth sprocket on the rear for my weight. And as for downshifting thats not the issue there is definitely a sound and i was just curious if anyone knew what causes it mechanically.

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You just need to listen to what people are telling you, you are lugging the engine. The revs are too low for the speed you are doing and the gear you are in. It's not good for the engine.

 

A gear lower and you'll be fine, bring the revs up ma touch mate.

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if at low rpms then I would say down shift, chain slap on top of swingarm-you can check this by having someone next to you look at it to see if chain is jumping up n down- or engine is just under a low rpm load and chugging.

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Mike in Fresno: thanks bud that was it...chain slap on the swingarm. Adjusted right to spec too. Went one more notch on the snail adjuster and knock went away. Problem is I don't like running the chain that tight and from notch to notch there is no in between like a slide adjuster.

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