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Gearbox Knock


alexanderfoti
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Hi all


My fazer has an annoying knocking noise.


When you throttle on - Knock


Throttle off - knock


Only does it in gear, and I can feel it through the bike, but can phase it out with use of the clutch.


Here is a video of it:


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Any idea if thats normal?

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I will have the sprocket cover off tonight and have a look.


Its moving as the tension is changing from the top to the bottom at the same time, but the sound is coming from the front of the engine rather than the chain area.

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Just got home, pulled the front sprocket cover off.


The slack is inside the gearbox, It moves nearly a tooth in either direction in gear. Sprocket bolt is done up nice and tight and hasnt moved in relation to the washer.


I have tensioned up the chain a little bit more, just to eliminiate some of the slack there.


Will see what its like tomorrow on the way to work.

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you will get a bit of backlash in the gearbox the sprocket will move while in gear


check for tight spots in the chain check cush drive rubbers it could be too much slack in the chain also check rear wheel bearings

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Others have suggested checking the Cush Drive rubbers....and I'd agree with that also.......oil been changed recently?......can make a difference to gearbox noise if it's changed regularly...... 8-)

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I wouldn't touch anything else now and see if the chain tension has sorted it, it could be that it was too loose and causing a lot of back lash when you powered on and off

 

My thoughts as well, although I did check the chain slack before I left with me sitting on the bike, 30mm exactly, had a friend measure it, so it was "within" spec.

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I wouldn't touch anything else now and see if the chain tension has sorted it, it could be that it was too loose and causing a lot of back lash when you powered on and off

 

My thoughts as well, although I did check the chain slack before I left with me sitting on the bike, 30mm exactly, had a friend measure it, so it was "within" spec.

 

Did you check the chain tension in more than one point along the chain?....could have tight and looser spots along its length...... 8-)

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I wouldn't touch anything else now and see if the chain tension has sorted it, it could be that it was too loose and causing a lot of back lash when you powered on and off

 

My thoughts as well, although I did check the chain slack before I left with me sitting on the bike, 30mm exactly, had a friend measure it, so it was "within" spec.

 

Did you check the chain tension in more than one point along the chain?....could have tight and looser spots along its length...... 8-)

 

I did :( A mystery on me to be fair, will see what its like tomorrow and will report back :)

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yup your supposed to check the chain tension on the tightest part of the chain and if it has tight spots I would say its new chain time


although saying that you can usually hear and feel any tight spots as you ride

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TBH....my Sprint ST tends to knock if I'm not gentle with the throttle in the lower gears......just kinda adapted my riding on this bike to smooth out things at lower speeds........ :wink:

Anyway....tomorrow you may have an answer...... 8-)

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TBH....my Sprint ST tends to knock if I'm not gentle with the throttle in the lower gears......just kinda adapted my riding on this bike to smooth out things at lower speeds........ :wink:

Anyway....tomorrow you may have an answer...... 8-)

 

I will keep an eye :)

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When you say on tightest part, does that mean on the top run between the sprockets rather than the bottom run (that you can see in the video moving)

 


No


you check the tension in the same place all the time at the bottom and you turn the wheel checking the tension until you find the tightest part at the bottom :)

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