3rd gear rattle

GavinJuice · Oct 2, 2016

While in 3rd gear I seem to be getting a rattle sound that is only present while moving. No other gear brings out this sound. It's not loud but I cannot decipher where it is coming from.

The chain is tensioned properly, tire pressure good, valve lash in spec, exhaust-mufflers-hardware all tight, all fluid levels up to snuff...

Are there any common issues with third gear that attribute to the gearbox?

What else could I be missing?

Thanks Gavin

Danno · Oct 2, 2016

Is it third gear (driven) the kickstart engages? If so, it could be w weak return spring allowing the kicker gear to rattle against the driven gear.

L.A.B. · Oct 2, 2016

Danno said:
Is it third gear (driven) the kickstart engages?

No, it's 1st.

CanukNortonNut · Oct 2, 2016

GavinJuice said:
While in 3rd gear I seem to be getting a rattle sound that is only present while moving. No other gear brings out this sound. It's not loud but I cannot decipher where it is coming from.

The chain is tensioned properly, tire pressure good, valve lash in spec, exhaust-mufflers-hardware all tight, all fluid levels up to snuff...

Are there any common issues with third gear that attribute to the gearbox?

What else could I be missing?

Thanks Gavin

Gavin,
I also get a 3rd gear whine which is present when running in that gear. I have over 30k on gearbox and no issues I attribute it to the gear-train of the AMC box. I run a belt drive system but that doesn't change anything in the gearbox. This spring I replaced 4th gear sleeve bushes and 1st gear bush. New gear oil and keep on keepin on. :wink:
Just ride it.
Cheers,
Thomas
CNN

bill · Oct 2, 2016

if it is a rattle in just one gearit is VERY common for these gears to shed teeth. IMHO i would be going inside for a look before more damage is done if it is a bad gear. gear whine is common in some gear sets but is not an issue to longevity.

CanukNortonNut · Oct 2, 2016

bill said:
if it is a rattle in just one gearit is VERY common for these gears to shed teeth. IMHO i would be going inside for a look before more damage is done if it is a bad gear. gear whine is common in some gear sets but is not an issue to longevity.

Like bill stated

Gavin'
if you want piece of mind then it is no big deal in opening the box and checking the gear train. Pay particular attention to the bushes on 4th sleeve gear and 1st. Check the layshaft bearing and make sure it has been changed to the Superblend type or Mick Hemmings ball bearing. Check also the kickstart pawl. Look for Brinelling pitting on the faces of the spur gears.
A weekend job if you are mechanical and have the tools and replacement spares. :wink:
Cheers,
Thomas
CNN

bill · Oct 2, 2016

the gears i see with the most trouble are 1st main 2nd pair 3rd pair and 4th main. i have broken 6 gears both shafts both forks 2 bearings and the main case all at once. you don't want a wayward tooth or other loose part to get between a gear pair as it will get REAL expensive or cause bodily injury if it locks up on the road at speed.

concours · Oct 3, 2016

Mine was a second gear "thump thump thump" not real loud.... and it was still operating fine.

Check out the first couple images here: some-andover-norton-transmission-parts-quality-escapes-t22412.html?hilit=Transmission

As mentioned above, take it out of service a moment and have a look.
When I think of how my mortally wounded gearbox could have locked up & put me on my face... :shock: :!: :|

bill · Oct 3, 2016

i heard that one as you rode off and called you to tell you to park it NOW do not pass go or collect $200.00

concours said:
Mine was a second gear "thump thump thump" not real loud.... and it was still operating fine.

Check out the first couple images here: some-andover-norton-transmission-parts-quality-escapes-t22412.html?hilit=Transmission

As mentioned above, take it out of service a moment and have a look.
When I think of how my mortally wounded gearbox could have locked up & put me on my face... :shock: :!: :|

concours · Oct 5, 2016

bill said:
i heard that one as you rode off and called you to tell you to park it NOW do not pass go or collect $200.00

concours said:

Mine was a second gear "thump thump thump" not real loud.... and it was still operating fine.

Check out the first couple images here: some-andover-norton-transmission-parts-quality-escapes-t22412.html?hilit=Transmission

As mentioned above, take it out of service a moment and have a look.
When I think of how my mortally wounded gearbox could have locked up & put me on my face... :shock: :!: :|

Click to expand...

"....awe Dad, me & the boys were headed to the beach :cry: "

3rd gear rattle

GavinJuice

Danno

L.A.B.

Moderator

CanukNortonNut

bill

CanukNortonNut

bill

concours

bill

concours

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