Gearbox "Shunt"

[alexanderfitu]

Hi all


I had a long ride out on the fazer today and noticed that there is a fair bit of gearbox/drivetrain shunt on my fazer, eg, throttle off, clunk, throttle on, clunk. Is this normal on the fazers or just on mine?

[darrsi]

Chain tightened correctly?


Not totally sure but if it's what i think you mean then it's normal in lower gears.

[alexanderfitu]

I checked the chain tension recently and its spot on.

If its normal then im happy, I will have a double check of axel bolts and things are tightened.

[red98]

yeh  i was going to say chain aswell.......how about too much slack in your throttle cable 

[Andy FZS]

Or too much slack in the pilot

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[alexanderfitu]

heh, to be fair, I was using my bluetooth headset for music on the journey, so it could be that I was being a bit sensitive

[Fazerider]

As well as the throttle cable I'd check carb balance.
Having said that, mine has more drivetrain slop than I'd like. With the bike on the centrestand and in gear I can rock the drive sprocket backwards and forwards though one whole tooth's worth of movement... I wonder how that compares with yours, or with anyone who has a low mileage example.

[alexanderfitu]

Aha it might be the sprocket then, I recently changed the sprocket nut for the larger one.

I will double check the free play at the sprocket side, if yours is moving that much then thats where my slop is coming from.

Ill have a look tonight.

[limax2]

Aha it might be the sprocket then, I recently changed the sprocket nut for the larger one.

I will double check the free play at the sprocket side, if yours is moving that much then thats where my slop is coming from.

Ill have a look tonight.

I think Fazerider is referring to the free play inside the gearbox rather than the fit of the sprocket itself, so nothing to do with the sprocket nut. (Unless it's come off!). A certain amount of free play, measured at the sprocket as mentioned, is normal. It is due to normal clearances in the gear drive train but mainly in the gear drive dogs in the mating slots.
Reducing the clunk is a lot to do with general feel for the throttle responce and a slack cable etc. will make that more difficult. (Not to mention tapping out the music in your ears  ).

[alexanderfitu]

Ah right I see.

Yeah Im not that bothered if its normal

It was a long boring journey round the m25, its either silnence with ear plugs or music with ear plugs

I have started shifting at different points, and using different clutch amounts fo reduce it, I wonder if its one of those things that I will get used to.

[alexanderfitu]

I have managed to put together a quick video.

I am moving the back wheel with the center stand on. The noise is still there with the engine running and bike in gear + clutch in, have a listen:

http://youtu.be/3TsgwTx0NgU

If its normal, then im happy

[darrsi]

No, that ain't normal, but i haven't got an answer for you either ???

[alexanderfitu]

Sad days, I wonder what it is.

[His Dudeness]

can you be a bit more specific in where the noise is coming from? like rear wheel area, engine area etc.

[alexanderfitu]

Comes from the gearbox sprocket area. Defo not the rear wheel, and there is no movement in the rear sprocket.

[His Dudeness]

not sure what it is then. doesn't sound good though. was it happening before you changed your front sprocket? maybe take the chain off and check whether it's the sprocket causing the excessive free play or if it's something in the gearbox. probably best if you don't ride it until you know what the problem is.

[alexanderfitu]

It wasnt making the noise before, but it didnt start straight after either.

I will check the sprocket nut againt before I shoot home.

[alexanderfitu]

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.

[Fazerider]

That seems to be about the same amount of slop as my 70,000 mile gearbox has, perhaps a bit less. As Limax says, there's bound to be some since the cogs have to have freedom to slide on the shafts and need clearance to allow for thermal expansion etc.
It would be interesting if someone with a nice crisp low mileage example could try the same measurement.

[alexanderfitu]

Well that's fair enough, it's a shame as mine only has 17,000 on it! It's the most annoying during low speed riding.

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