Worm drive hunger?

[Ernesto]

I wonder who or what chewed up the worm drive on my
mate's SF2.
Both washers are there, no signs of wear on the crowngear.
As  visible on the second pic, the debris landed in a groove.

Any ideas what we should check to keep the spare drive
from sharing the fate?

Ernesto

 

[sfcpiet]

Ernesto,

Check how free the drive of the speedo head revolves.  You may find that it starts to bind after a couple of revolutions, but will free up immediately if turned backwards 1/2 revolution.

With time, wear causes the internal drive gears to bind slightly, putting pressure on the worm and crown gears of the wheel drive.  As spare parts are not generally available for the ND speedos, only alternative is to source a newer/better instrument, or have somebody make new gears.

Laverdas were well made with top class components, but not built for eternity!  Everything will wear out eventually.

piet

 

[Terry Dymond]

I strip, clean and grease mine every time the front wheel comes off. One of those little things that gets missed.

 

[sfcpiet]

I strip, clean and grease mine every time the front wheel comes off. One of those little things that gets missed.

Doesn't help if the instrument is knackered...

Those that I have had to replace were all well lubed, they gave up nevertheless.  A mate replaced his speedo drive gears three times before I found the binding gears in the speedo.  Replaced the speedo, drive has worked faultlessly since.

piet

 

[Vince]

Years ago my speedo stopped working,so I had it rebuit.Still didnt work,thats when I found the stripped worm.At the time I was pissed at spending on the wrong fix,seems I did do it in the right order in the long run.

 

[Terry Dymond]

Had mine strip, fortunately I had a spare worm and crown gear. Put the failure down to lack of preventive maintenance.

 

[chrisk]

Had mine strip, fortunately I had a spare worm and crown gear. Put the failure down to lack of preventive maintenance.

The worm has turned.
something that you say when someone who has always been weak and obedient starts to behave more confidently or take control of a situation:
Yesterday she just came in and told him to stop bossing her around. 'The worm has turned!'

or, in this case, hasn't.

 

[Ernesto]

Thanks, Piet.
Will check next week.
Ernesto