knocking leant over after gearbox rebuild

Snorty · World Chat Champion Joined: 13 Oct 2010 Karma :

So I've just swapped out the well and truly fucked gearbox from my gsxr as it was slipping out of 4th. New (used but no wear at all on dogs) gearbox dropped in. Bike starts up, but there's a knocking when it's on the side stand. If you put the bike straight up or lean to the right, the knocking stops. All gears select fine and no knocking when in gear. Any ideas? I didn't replace the selector forks as they 'looked' ok - ie not obviously bent and I'm thinking maybe something to do with that?

This doesn't happen in gear at all when leant to either side, so that rules out anything to do with the crank
Only when leant to one side as well... so maybe a bent selector fork slightly knocking a cog onto another?
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Current: Yamaha FZ1 '07 | GSXR 750 SRAD

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pepperami · Super Spammer Joined: 17 Jan 2010 Karma :

Thrust washer missing?

Different parts from different model or year? (specs change)

All gears select fine and no knocking when in gear.
Gear box ok , clutch ?

EDIT : try asking this in Workshop?
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uberkron · Crazy Courier Joined: 12 Nov 2012 Karma :

Did you disturb any engine mounts doing this job? The sidestand being involved sounds odd. I also tend to think that gravity would not have that much influence on an engine/gearbox.
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uberkron · Crazy Courier Joined: 12 Nov 2012 Karma :

Did you disturb any engine mounts doing this job? The sidestand being involved sounds odd. I also tend to think that gravity would not have that much influence on an engine/gearbox.
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iooi · Super Spammer Joined: 14 Jan 2007 Karma :

Snorty · World Chat Champion Joined: 13 Oct 2010 Karma :

m3-paul · Spanner Monkey Joined: 03 Feb 2009 Karma :

Something to do with the shift drum moving very slightly when in the neutral position? Can't imagine how a shift drum would have the ability to move in a sideways fashion but worth checking I guess.
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The Disapproving Brit · World Chat Champion Joined: 10 Sep 2008 Karma :

Can't help, but I have almost the exact same issue, except mine persists in gear. I'd be interested to know what you find.
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Paddy Blake · World Chat Champion Joined: 29 Jun 2006 Karma :

I would have put the drum and forks from the new gearbox in aswell.
Check the numbers on both sets of forks and see if they are different.

stickybackbob · Trackday Trickster Joined: 23 Mar 2013 Karma :

No chance of one of the gear wheels being put in the wrong way round?

Some gears (without the dogs on) can appear to go in either way when in reality, they only work properly one way round Smile

Snorty · World Chat Champion Joined: 13 Oct 2010 Karma :

Old selector forks were worn away... put new ones in which are mint.

The noise persists! No idea what it could be now, but as it's only when the bike is leant to the left in neutral I'll put up with it for now...

Gearbox is so smooth regardless.
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Current: Yamaha FZ1 '07 | GSXR 750 SRAD

Past: CB125TDC | TZR125 | GPZ500 | CBR600F3 | ZX9-R | GSXR1000 K4

_mjs_ · Could Be A Chat Bot Joined: 23 Feb 2012 Karma :

Paddy Blake · World Chat Champion Joined: 29 Jun 2006 Karma :

Just thinking the only time I came across this problem was when a garage left out the half-ring retainer from the bearing behind the clutch.
This allowed the shaft to move in neutral and caused that noise.
In gear the forks stopped the shaft from moving.

Any chance you left half-ring out.

metalizzer · L Plate Warrior Joined: 09 Jun 2015 Karma :

hi

got to dig this topic up from the grave... i´m experiencing exactly the same thing with a xrv 750 after engine rebuilt . only does the noise on neutral on the stand... did you solve the problem! it´s driving me nuts!

Snorty · World Chat Champion Joined: 13 Oct 2010 Karma :

To be honest, I've just ignored it. I am going to split the gearbox at some point when I get a spare weekend, could be what Paddy said, or something else.

Not sure if there is some kind of thrust washer I may have left out.
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Current: Yamaha FZ1 '07 | GSXR 750 SRAD

Past: CB125TDC | TZR125 | GPZ500 | CBR600F3 | ZX9-R | GSXR1000 K4

Vincent · Banned Joined: 16 Oct 2006 Karma :

I'd go with Peperami's idea of the thrust washer either missing or incorrect size. I'm pretty sure these are fitted to each gearbox and can vary on different engines of the same bike.
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spikenipple · Crazy Courier Joined: 20 Nov 2007 Karma :

metalizzer · L Plate Warrior Joined: 09 Jun 2015 Karma :

you guys are saying that everything probably is correctly mounted but it can be a washer out of specs? i did open the engine because of a worn output shaft but all the spline washers and cir clips on the new shaft are from the old one.
i took special attention assembling the shaft every gears or washers before assembly on the shaft i looked on the manual to see the corect position.
if you look at a parts manual for the XRV 750 all engines interiors are the same and have the same honda number parts no matter the year of the bike

Vincent · Banned Joined: 16 Oct 2006 Karma :

If I understand it correctly, when the gearboxes are assembled, the end float is measured and the appropriate shim used to get it to within spec. Your using a shaft and box that havn't been measured together. It could be that your replacement shaft needs a thicker washer with the old box.
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metalizzer · L Plate Warrior Joined: 09 Jun 2015 Karma :

metalizzer · L Plate Warrior Joined: 09 Jun 2015 Karma :

[quote="Snorty"]To be honest, I've just ignored it. I am going to split the gearbox at some point when I get a spare weekend, could be what Paddy said, or something else.

Not sure if there is some kind of thrust washer I may have left out.

yes, that´s what people keep telling me. but i fallowed every step on assembling the shaft by the bike´s shop manual. the washers and cir clips have a correct position to be mounted on the shaft that´s why i took so much care.
how do you ride the bike??? you have always to be careful not to start it on the side-stand or lean it to the left on neutral!

Vincent · Banned Joined: 16 Oct 2006 Karma :

The thrust washers won't be in the parts list as they're specific to each bike and put in place at the factory. If this is the problem, I suppose you'll need to measure the end float on the main shaft and find out the specs. Either that or guess and use what you have. Were there any thrust washers on the selector shafts? These washers sometimes stay stuck to the inside of the cases and get missed.
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metalizzer · L Plate Warrior Joined: 09 Jun 2015 Karma :

what i could of done wrong was probably assemble one or more thrust washer and snap rings on the wrong position since they are chamfered (rolled) and must be installed facing away from the thrust load! can this be it? i remember being a bit confused about this

Vincent · Banned Joined: 16 Oct 2006 Karma :

Could be.
I was always told to spend ages operating the gears with my hands before assembling the gearbox to make sure everything meshed up correctly and nothing was fouling.
Do you have a Yamaha Workshop manual? The end float should be specified in there.
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metalizzer · L Plate Warrior Joined: 09 Jun 2015 Karma :

yes , i´could´nt even do it without the manual.