Author Topic: Gearbox "Shunt" (Read 3922 times)

alexanderfitu · « **on:** 03 February 2013, 09:09:29 pm »

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 · « **Reply #1 on:** 03 February 2013, 10:32:36 pm »

Chain tightened correctly?

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

alexanderfitu · « **Reply #2 on:** 04 February 2013, 08:02:10 am »

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 · « **Reply #3 on:** 04 February 2013, 09:15:56 am »

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

Andy FZS · « **Reply #4 on:** 04 February 2013, 09:45:43 am »

Or too much slack in the pilot:P

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alexanderfitu · « **Reply #5 on:** 04 February 2013, 09:46:24 am »

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 :P

Fazerider · « **Reply #6 on:** 04 February 2013, 12:26:29 pm »

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 · « **Reply #7 on:** 04 February 2013, 12:58:42 pm »

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 · « **Reply #8 on:** 04 February 2013, 02:40:26 pm »

Quote from: alexanderfitu on 04 February 2013, 12:58:42 pm

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 · « **Reply #9 on:** 04 February 2013, 02:43:34 pm »

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 · « **Reply #10 on:** 05 February 2013, 02:54:33 pm »

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 · « **Reply #11 on:** 05 February 2013, 03:10:38 pm »

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

alexanderfitu · « **Reply #12 on:** 05 February 2013, 03:11:51 pm »

Sad days, I wonder what it is.

His Dudeness · « **Reply #13 on:** 05 February 2013, 03:16:53 pm »

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

alexanderfitu · « **Reply #14 on:** 05 February 2013, 03:18:16 pm »

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

His Dudeness · « **Reply #15 on:** 05 February 2013, 03:31:07 pm »

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 · « **Reply #16 on:** 05 February 2013, 03:47:50 pm »

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 · « **Reply #17 on:** 05 February 2013, 06:09:13 pm »

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 · « **Reply #18 on:** 05 February 2013, 07:23:25 pm »

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 · « **Reply #19 on:** 05 February 2013, 07:29:10 pm »

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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limax2 · « **Reply #20 on:** 06 February 2013, 10:13:15 am »

To hopefully put your mind at rest you could see what a few other bikes feel like when on a centre stand and rocking the back wheel. (Best to ask permission first or you might get attacked

).
I know you said it didn't do it before the sprocket change, which is a bit worrying, but it is easy to kid yourself when you become super sensitive to a possible problem.
Good luck.

darrsi · « **Reply #21 on:** 06 February 2013, 10:40:45 am »

Just for the record, i've just been outside and given the bike a bit of TLC on my week off, and gave the rear wheel a good rocking back and forth and can report there was no play at all.
My bike's just touched 40,000 miles on the clock.

alexanderfitu · « **Reply #22 on:** 06 February 2013, 10:42:04 am »

Was that in gear Darrsi?

alexanderfitu · « **Reply #23 on:** 06 February 2013, 10:43:15 am »

Quote from: limax2 on 06 February 2013, 10:13:15 am

To hopefully put your mind at rest you could see what a few other bikes feel like when on a centre stand and rocking the back wheel. (Best to ask permission first or you might get attacked ).
I know you said it didn't do it before the sprocket change, which is a bit worrying, but it is easy to kid yourself when you become super sensitive to a possible problem.
Good luck.

Yeah I will have a look with at my xj600 in the same situation. Its eniterely possible that its been there the whole time and im just noticing it now.

darrsi · « **Reply #24 on:** 06 February 2013, 10:50:57 am »

Quote from: alexanderfitu on 06 February 2013, 10:42:04 am

Was that in gear Darrsi?

DOH!!!
No it wasn't

I'll have another go when i get a minute.........but the bike does look all nice and shiny now if that helps at all?