Selector Drum Detent Arm

[SandPebbles]

Lets talk detent arms.  Upon disassembling the gearbox of my '74 triple, I found an anomaly
with the detent arm.  The "top hat" or flanged piece that holds the roller captive showed signs
of quite a bit of wear.  The lower half of the flange or rim (that is oversized to hold the roller) looked
as if someone took a file and chamfered the bottom edge.  It looks filed from the middle of the circle
down to a sharp edge at the bottom.

As the roller is still fully captive and the wear looks so man-made, I thought this may be intentional
for some performance reason.  :-\

Still, I found a used detent arm for sale and purchased it.  While not as severe as my original, the
second detent arm indeed shows signs of the same wear.  This begs the question...is this a common
occurrence with these gearboxes?  Is it a problem to run them with this wear?  I just purchased a new
detent arm spring from Wolfgang, should I  have purchased a new arm as well?  I am curious to hear
the consensus on this matter.

Keith

 

[mcnicol]

Keith, pictures of this sort of thing are kind of tricky with a cell phone camera, but give it a try. I don't have an answer for you but I'd really like to see what your DPO mod looks like, haven't come across this one before.

Ken

 

[breganzane]

Those are are pretty rough and ready out of the factory, most likely original.  But yes, photos please.

 

[sfcpiet]

Only Laverda models that have problems with detent arm wear are the Zane crap-heaps.  The rollers are often very close to falling off!

Have never come across an arm that had failed in normal service, and because they work as inconspicuously as they do, they are rarely butchered.  Markings are more than likely to be factory original.

piet

 

[SandPebbles]

I knew I photo would be helpful, but I am about 50% successful at downloading pics on the forum.

Here it goes.....

The picture is in the gallery.  The lower arm in the picture is my original.  The darker colored arm
is the item I recently purchased.  I hope the chamfer is visible in the image.  

Keith

 

[sfcpiet]

Keith,

There is nowhere in the casing the arm could wear at that point, reckon you now have a good spare that you will (hopefully) never need!

Choose whichever suits your fancy and fit it.

piet

 

[redax5]

just checked my spare detent arms, out of 6 detent arms I have in stock 2 have that taper on them, other 4 have no taper
is factory standard so chosse the cleanest and install that one

HTH
Red

 

[SandPebbles]

Thanks gentlemen, it is good to put to rest any uneasiness about the internal parts.

Keith

 

[phil37]

  I have in stock 2 have that taper on them, other 4 have no taper
is factory standard so chosse the cleanest and install that one

The ones with a chamfer were special factory lightened jobbies fitted only to works racers