GT 380 Gear box strange noise

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arthur
Posts: 68
Joined: Wed Jun 17, 2020 8:55 pm

GT 380 Gear box strange noise

Post by arthur »

Like the title says my 75 380 has a weird noise in the gear box its a sort of bearing whine a kind of wooo wooo wooo imagine the sound of a whirling a rope round your head , fairly low frequency and it only happens in 6th under load
but not speed related. in as much as it doesn't increase in speed or volume in time with road speed . Has anybody an idea what it could be?
Other than this she runs fine if a bit thirsty. a bit of a mare to start when cold but 1st kick when warm the more I ride her the better it gets, and it surprising what you see in the countryside trundling along instead of Hooning at licence shredding speeds

Also whilst I am here has any one got a good right hand inner exhaust?
I have looked on the e bay but inner's seem to be in short supply
Mine has collapsed inside, the discs / rings inside have all come loose there is nothing to mount the baffle into its LOUD and I can't imagine it s good for gas flow
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Alan H
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Location: Wombwell, Republic of South Yorkshire

Re: GT 380 Gear box strange noise

Post by Alan H »

arthur wrote: Wed Nov 10, 2021 9:13 pm Like the title says my 75 380 has a weird noise in the gear box its a sort of bearing whine a kind of wooo wooo wooo imagine the sound of a whirling a rope round your head , fairly low frequency and it only happens in 6th under load
but not speed related. in as much as it doesn't increase in speed or volume in time with road speed . Has anybody an idea what it could be?
Other than this she runs fine if a bit thirsty. a bit of a mare to start when cold but 1st kick when warm the more I ride her the better it gets,
Do an oil change and ride it more.
Proof that four strokes are over complicated
arthur
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Joined: Wed Jun 17, 2020 8:55 pm

Re: GT 380 Gear box strange noise

Post by arthur »

I try to run her at least once a week Now 350 miles on the odometer and nothing has fallen off yet!
Although fifty mile in on hit is about as much as my knees can take :lol:
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slosher
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Location: Walsall,Black Country

Re: GT 380 Gear box strange noise

Post by slosher »

Nearly fifty year old gearbox's do start to show a little wear mainly 5th and 6th gears suffer on GT's may also be slight wear in the output shaft bearing when under load in 6th gear.What sort of mileage is on the bike Arthur :?:
GT750L
GT550L
TL1000 97s
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Loctite Trained Engineer :lol:(since having the Bonnie)
arthur
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Joined: Wed Jun 17, 2020 8:55 pm

Re: GT 380 Gear box strange noise

Post by arthur »

Off the top of my head she's on about 29,000 although who's to say the clocks are genuine?
I did think about the output shaft bearing but the noise doesn't seem fast enough and it only happening in top threw me off track a bit.
I will treat her to some fresh oil and see what happens
But on the pot holed tracks they laughingly call" B" roads here in the Marches getting into top is a bit of a rarity :D
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canaletto5
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Location: Derbyshire

Re: GT 380 Gear box strange noise

Post by canaletto5 »

My 76 380 made the same noise and I tracked it down to the plastic points driven gear meshing on the metal drive gear. When I looked at the gears , the plastic gear boss was cracked so I fitted a new one along with a new drive gear. It made absolutely no difference. Gearbox whine tends to be on synchromesh set ups and as these are constant mesh I really wouldn't worry about it. Btw, how can you hear it above the exhaust noise? :lol:
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Gary66
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Re: GT 380 Gear box strange noise

Post by Gary66 »

My 380 was the same in 5th gear, I just used to short shift through to 6th and enjoy the bike regardless
arthur
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Re: GT 380 Gear box strange noise

Post by arthur »

Ha!! Chin on the clocks, left hand on the top of the fork leg, lots of noise from the engine, go fast enough you leave the exhaust din behind you.
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BAZ
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Re: GT 380 Gear box strange noise

Post by BAZ »

The teeth on the gear will be worn, avoid using it till you can strip down. Cheers Barry.
arthur
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Re: GT 380 Gear box strange noise

Post by arthur »

Good thing Winter is approaching more time in the workshop :lol:
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