LCGB Forums

harps2 wrote:Well finally put her all back together with new shims, checked all gears for any wear/damage everywhere and managed to increase size of gearbox shim to reduce clearance - Guess what ---....




STILL THE BLOODY SAME !11

the noise only goes away when you PULL CLUTCH INN AND SELECT GEAR - let clutch out and noise returns.................................

Warkton Tornado No.1 wrote:If the noise disappears with clutch pulled in & gears engaged, then the problem is most likely within the gearbox area.

My suspicions would be:

something is catching on the first gear or the inner clutch top plate (typically the kickstart) or;

the gears are noisy through too much clearance, a mismatch of gears or a broken tooth/teeth.

If it isn't that & you have the correct shimming to give as close to 0.003" as is possible, & the gears are not missing any teeth, then you should check the only things likely I believe to be remaining, which are mismatched gears (Sticky's book has number of teeth & outside diameter), a bad endplate bearing/journal/lay-shaft journal or the cursor itself.

We all sense your frustration, but if the noise disappears with the clutch pulled in, whilst in gear, that puts all four ratios under a slight load due to the dragging of the clutch. That will cause the quietening of any noisy gears.

Although I would still tend to call the problem "mismatched gears" it was not especially helpful if all you have to go on is the number of teeth & outside diameter by which to check! So, I apologise but will endeavour to try & help:

The problem you have will most likely be due to (especially) "brand new" gears that are manufactured badly & therefore badly mesh. All gears have a curved face (profile) that should conform to a "pressure angle" & any slight deviation will result in "ringing" which results in a noisy gearbox.

Likewise, all gears are produced to a PCD (Pitch Circle Diameter) that is the true diameter which meshes with the true diameter of another gear. So, even if the profile (mentioned above) is correct, if the PCD is incorrect &, say, undersized, the result will be an incorrect mesh with too much clearance with the gear it should mate with.

Where might all of this conjecture leave you?

The best way to find out is to borrow another complete 'quiet' gearbox of the same type & substitute it completely, or gear by gear until you find the likely culprit.

I have no idea of how feasible that may be for you, & how helpful it is to mention that I have a considerable amount of gearboxes (especially TV200) but if I can help, I will.

Here's a short video of the noise - feedback please!

https://www.youtube.com/watch?v=LBvSpxFdHaE

harps2 wrote:Here's a short video of the noise - feedback please!

https://www.youtube.com/watch?v=LBvSpxFdHaE

My knee jerk reaction?:

Kickstart.

The pawl teeth are catching on first gear & not fully disengaged.

See what other people say first, before rushing in(!) but there is a 'fix' for this many of us can tell you about.

Warkton Tornado No.1 wrote:

harps2 wrote:Here's a short video of the noise - feedback please!

https://www.youtube.com/watch?v=LBvSpxFdHaE

My knee jerk reaction?:

Kickstart.

The pawl teeth are catching on first gear & not fully disengaged.

See what other people say first, before rushing in(!) but there is a 'fix' for this many of us can tell you about.

I have tried removing the piston/spring etc and refitted side case then bump started - noise is still the same....

harps2 wrote:

Warkton Tornado No.1 wrote:

harps2 wrote:Here's a short video of the noise - feedback please!

https://www.youtube.com/watch?v=LBvSpxFdHaE

My knee jerk reaction?:

Kickstart.

The pawl teeth are catching on first gear & not fully disengaged.

See what other people say first, before rushing in(!) but there is a 'fix' for this many of us can tell you about.

I have tried removing the piston/spring etc and refitted side case then bump started - noise is still the same....

I'm amazed!

As I also said in my PM to you, it sounds like the pawl not disengaging.

If not that, the mind boggles as to why it is such a 'kickstart type' noise!

If the fasteners holding down the endplate are fouling on the crown wheel/chain (too long an M7 stud, too tall an M7 nut &/or washer) I suppose it could sound similar.....

Any other ideas out there? - please listen to the youtube video!

I agree completely that that's the kickstart teeth.

I've had them where new ones were tight in the slot and I had to dremmel them. Maybe kickstart ramp needs adjusting to pull the pawl down further?

dickie wrote:I agree completely that that's the kickstart teeth.

I've had them where new ones were tight in the slot and I had to dremmel them. Maybe kickstart ramp needs adjusting to pull the pawl down further?

Sorry but as already mentioned - I have removed kickstart piston and then refitted side case and bump started - noise is still the same so can not be catching on teeth!

Sorry. Long thread and I'm lazy.

dickie wrote:Sorry. Long thread and I'm lazy.

thanks for feedback anyway

My first reaction as was WT was KICKSTART.

Change the chain.

Random half-arsed thought...

It sounds really like something catching on kick start teeth. Is return spring incorrectly seated and somehow catching? I had a lot of problems with my last one.

Here's a weird suggestion but needs must !! remove side case then bump start ru n for a moment or two watch your fingers though and oil being thrown about

steve t wrote:Here's a weird suggestion but needs must !! remove side case then bump start ru n for a moment or two watch your fingers though and oil being thrown about

Beat me to it !! Only down side is the clutch won't work, but may give some idea as to where the noise is coming from.

MickYork wrote:

steve t wrote:Here's a weird suggestion but needs must !! remove side case then bump start ru n for a moment or two watch your fingers though and oil being thrown about

Beat me to it !! Only down side is the clutch won't work, but may give some idea as to where the noise is coming from.

I think that the suggestions are good ideas. However, It would take some skill to bump it with no clutch to pull in & then crash it out of gear, but it may be possible

An alternative take on the same principle would be to remove the plug & spin the motor with a powerful drill, as I do to check ignition timing with a strobe when I don't want to take a scooter off the bench/late @ night. You'd need a good, six point 14 mm AF hexagon socket & hexagon/square adaptor, but it would be a lot safer, IMHO

Try putting in an extra couple of chaincase gaskets and try again to see if the noise changes at all

In some cases this noise can come from engagement between the actual kickstart shaft end touching the side of the first gear even with the piston and spring removed. This situation usually results in the kickstart piston bore getting burred over preventing the piston from springing out properly. Inspect the end of the piston bore for signs of contact. If this turns out to be the case, then check you have the shaft shimmed up properly. Failing that, a thicker chaincase gasket may overcome the problem.

I saw the picture with the kickstarter shaft but no kickstart lever, well bump start it and clamp a pair of mole grips on the shaft and pull it UP a bit see if the noise changes/goes.

LATEST UPDATE 16th July

OK well after good suggestions by a couple of you guys, I bump started without the side casing on and guess what - the noise is STILL THE SAME

it sounds like a rubbing noise and not on the total revolution so I guess it means stripping out the gears again and having another look................................


Suggestions please anybody ????? - can't believe this has only happened to me??

well at least we have understood its not the sidecase/clutch/kickstart/chain catching anywhere !!!

the saga continues and thanks for the help to date !~-----------------------------------------

In my PM to you on the 22nd June I suggested that it could be the selector curser catching on first or second gear,I also suggested that you might have a gear in the wrong way around.Seeing as you are stripping the gearbox to have a look,you might pay special attention to these areas.