Detent plungers

[dxhall]

I have again pulled the transmission from the ‘07 Cal Vin.  This I have done because, when it is warm, the transmission will not shift into first or second gear.  The shift lever doesn’t bind up, and when I move the lever it feels like it shifts.  Except, it doesn’t.  It feels like the shift drum is moving when the lever is moved, but that the detent plunger doesn’t hold the drum in the new position and the drum just goes back to where it was when the shift lever is released.

This time, I compared the Cal Vin detent plunger to the plunger from one of my spare 5sp transmissions.  Here they are:




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The one with the hole in the center and with the flatter nose is from the Cal Vin.  When I hold the two plungers in one of the detent slots in the shift drum, the old one goes in much deeper and gives a more positive engagement. 

Does anyone know why these plungers would be so different?  Is the Cal Vin plunger a factory mistake?

[Scout63]

I would put it on the center stand and shift it up and down through the gears while off turning the rear wheel by hand.  Does it engage better way than the other?  The centering bolt on the back of the gearbox may be off center so that the lever doesn’t give the shifter a full throw one way. Also, check the gear shift lever to gear box connections. Finally, although this sounds stupid - is the detent plunger spring fitted?

[Antietam Classic Cycle]

This time, I compared the Cal Vin detent plunger to the plunger from one of my spare 5sp transmissions.  Here they are:




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The one with the hole in the center and with the flatter nose is from the Cal Vin.  When I hold the two plungers in one of the detent slots in the shift drum, the old one goes in much deeper and gives a more positive engagement. 

Does anyone know why these plungers would be so different?  Is the Cal Vin plunger a factory mistake?

The flatter nose detent plunger was the "improved" design that is supposed to make shifting better. I'm not really sure how it could. I'd try the earlier plunger.

[Wayne Orwig]

You of course got the answer from Charlie.

They switched to the flatter nose in about 2003, to make shifting a touch nicer. I have flattened the nose on a few of the older ones over the years, to make shifting easier.

Is it going into gear then popping back out, or not going into gear at all?

[dxhall]

The unhappy pattern is:

(1) leave shop with cold motor in first gear, shift easily into second
(2) ride for 20 minutes
(3) find at stop light that transmission is in third gear and won’t go into second or first
(4) get pissed off at this damn thing
(5) ride home in third gear

From the Harper’s diagrams, I see that the stock 2007 plunger (part no. 28234700) is the one with the flat nose, where the earlier one (part no. 55234700) is the conical one.

I think the next step is to put it back together with the old plunger and see what happens.  Since it works when it’s cold, there’s no way to bench test it.

[Scout63]

It sounds as if the box is loosening up when warm. I had the same problem when trying to shift a rebuilt box on the bench without tightening up the output shaft nut. Can you check to see if you have any excess fore and aft driveshaft play or if the rear gearbox cover screws are loose?  It may involve removing the rear wheel and maybe the swingarm. If the gearbox shafts move too much then they move rather than shifting the gears.

[dxhall]

The transmission is apart on my bench for the second time.  Last time I looked carefully at every piece of it.  Other than a need for a minor re-shim of the shift drum, there was nothing obviously wrong with it.  My only thought on it is that something was machined out of spec (width of the detent slots, for example) but I have no way of figuring out what it might be.

The fix for this kind of problem is to SELL THE DAMNED THING.  I won’t do to someone else what the seller did to me, though.

[moto-uno]

  As was mentioned earlier , the screw and locknut at the back that limits shifter travel is a good first check and I'm
rather a fan of the earlier detent plunger . I made a tool to pull the output shaft into it's fitted position and then
rechecked that all the shifter dogs were properly positioned . Good luck , that's a lot of work !  Peter