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Navigator ratched shaft spindle

Submitted by ulrich_hoffmann on Sun, 26/03/2017
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Light Twins

I noticed the ratched shaft spindle sticks out too far. The outer of the two o-rings is almost in fresh air!

photo IMG_20170326_125651198_zpsak1hvldq.jpg

I dismantled the gearbox once again and this is how the gearchange shaft looks like:

photo IMG_20170326_164142694_HDR_zpsqgmg2ham.jpg Too long? From a later style gearbox? Or from another model?

In the spare parts list the rachet shaft with the o-rings is listed as a separate part which is available from the NOC shop. How is it fixed to the gearchange shaft?

Also the whole gearchange shaft is available The pic in the NOC shop shows a shorter shaft.

Submitted by patrick_mullen on Sun, 26/03/2017

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I have never taken these shafts apart but I would suggest that a tap with a block of wood on the end of the spindle might reseat the spindle shaft back into the ratchet shaft. It doesn't give any useful information in the Maintenance Manual but they are listed, as you say, as two separate shafts in the Spare Parts List. The ends of the two shafts should be approx. flush when fitted through the gearbox outer cover.

Don't overdo the 'tap with a block of wood' - just a gentle knock to see if it moves - I suspect it will.

Maybe someone else has come across this before ?

Submitted by ulrich_hoffmann on Fri, 21/04/2017

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Well any attempt to "adjust" the spindle length failed. I ordered a new one from the NOC. See the difference:

photo IMG_20170417_120520057_zpsnzjgg6zz.jpg

Submitted by patrick_mullen on Fri, 21/04/2017

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No doubt about the difference in length. Have you tried extracting the ratchet shaft spindle from the ratchet shaft just to satisfy your curiosity? Presumably a previous owner has fitted a wrong part ? But what did it come from? The ratchet shaft and the cam segment look very similar on both items in the picture.

These gearboxes are supposed to be similar to those in some models of Francis Barnett and also some AJSs - so possibly a previous owner has obtained a part from one of these which "almost" fitted. It's a steep and costly learning curve as these machines get older. Both JPA and yourself have come upon some 'strange' modifications.

Here's hoping it all fits together nicely now,

Patrick

Submitted by ulrich_hoffmann on Tue, 25/04/2017

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What is the mest method to reasemble the pre 64 gearbox? The manual says put the selector in fourth gear, turning it as far clockwise as possible. I have some issues putting on the inner gearbox plate, something is blocking. When I only put in the mainshaft and layshaft with kickstarter shaft and without the gear selector it works. I can drive the gearbox plate home.

When adding the selector shaft the plate does not set on the bosses. I tried the new seletor shaft from the NOC. This morning I was able to get the longer indicator shat off my original selector, shortened it an hammered it back with a block of wood. Now it has the correct lenght. I ran out of time before going to work. Will try this shaft tomorrow.

Submitted by ulrich_hoffmann on Wed, 26/04/2017

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After the 15th or so attempt everything fits.

Exept the shortened selector spindle- too short now..Cry

Measure twice cut once!

 



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