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Navigator gearbox

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Navigator gearbox

Posted by John Pullen-Appleby at August 01. 2017

Hello All,

I am slowly making progress with the Navigator.  MY rolling chassis is about there--non standard as before BSA front end.  I do intend to fit a side stand.

 

I am about to start on the gear box and wondered if anyone had any inherited wisdom to impart.  I have got the gears in a pile ready to put on the shafts.  I am assuming that the sleeve gear  should be put in and the nut done up at this point.  There isd a sort of stainless steel ring that sppears to go into the oils seal behind the front sprocket--what is that all about.  Are there gaskets btween the gear cases?

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Re: Navigator gearbox

Posted by patrick_mullen at August 02. 2017

Hello John,

You are definitely making progress-it is always good to get to a rolling chassis.  One day you will locate a Roadholder front end but they tend to be very costly.

It's ages since I had a gearbox down in bits but I seem to remember the spacer you mention.  I think that all it actually is - a spacer.

The only obvious thing to mention about the gearbox is to check the condition of the layshaft bush. These can give trouble so if in doubt renew it now and it is recommended that you both locktite and peg it in position.  Other than that put the box together, unless something obviously needs sorting first, and test that it is all working.  It is easy enough to work on even when back in the frame.

Yes there should be a gasket between the cases.

NOC spares keep the layshaft bush.

This MK1 gearbox is not all bad and (except for the layshaft bush) is probably a better gearbox than the post 1963 version.

Patrick

Re: Navigator gearbox

Posted by John Pullen-Appleby at August 02. 2017

Previously patrick_mullen wrote:

Hello John,

You are definitely making progress-it is always good to get to a rolling chassis.  One day you will locate a Roadholder front end but they tend to be very costly.

It's ages since I had a gearbox down in bits but I seem to remember the spacer you mention.  I think that all it actually is - a spacer.

The only obvious thing to mention about the gearbox is to check the condition of the layshaft bush. These can give trouble so if in doubt renew it now and it is recommended that you both locktite and peg it in position.  Other than that put the box together, unless something obviously needs sorting first, and test that it is all working.  It is easy enough to work on even when back in the frame.

Yes there should be a gasket between the cases.

NOC spares keep the layshaft bush.

This MK1 gearbox is not all bad and (except for the layshaft bush) is probably a better gearbox than the post 1963 version.

Patrick

Hello Patrick,

It certainly seems substantially made with the selector plate  looking worthy of a a dockyard.  It was all working  when I got it which was quite remarkable as the bush you mention was loose in the case and in the outer cover I found this odd looking item  (see picture).

I have fitted a needle race to support the layshaft and used the head of the old bush (pegged ala BSA  etc) as a thrust washer.  Even then I can see the oil level will be critical.

 

I have replaced the funny little ally tin snipped out thing with a standard one which itself looks very unsubstantial.  What is all that arrange,ent--I can an indexing sping elsewhere--is it the positive stop to ping the pedal back after a change?

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Re: Navigator gearbox

Posted by patrick_mullen at August 02. 2017

Hi John,

The alloy 'thing' holds the gear change spring in position.  It often seems to be chewed up but as long as the gear change works there's little to worry about. There's a bit of an art putting the gear box cover plate back on as there are all sorts of 'loose' bits and pieces to hold together until the bits all engage in their respective slots.  After a few goes you become quite expert at doing this.

Patrick

Re: Navigator gearbox

Posted by John Pullen-Appleby at August 03. 2017

Hello Patrick,

The stainless object is a seal centre by all accounts but--it seems to be something you  have to push the seal over backwards as it has a head on it--I cannot see how iot could easily go throught the seal I have which--according to the spares scheme is the one.

 

It seems to crying out for some kind of a lead to put on it but I am loathe to start altering things.

 

Cheers

JPA

Re: Navigator gearbox

Posted by patrick_mullen at August 03. 2017

John,

Have you got this.

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Re: Navigator gearbox

Posted by patrick_mullen at August 03. 2017

More

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Re: Navigator gearbox

Posted by patrick_mullen at August 03. 2017

Sorry about the quality.  My laptop on Windows 10 won't speak to my old scanner so I'm using my ten year old computer. It is so slow but has a lovely keyboard and still works.

I think you are referring to item 78 in the illustration called the distance piece in the Norton maintenance manual.

Re: Navigator gearbox

Posted by Dan Field at August 03. 2017

Crikey that's complicated, I'm putting mine back together after replacing the layshaft bush as one unit, as it came out ... attached to the inner plate! I did when I was 18 so reckon I can do it again!

Re: Navigator gearbox

Posted by patrick_mullen at August 04. 2017

When I was 18 I had a BSA M20 - exWD- and it was extremely reliable but seriously slow (65mph flat out/ 75mph if you told some lies). A Norton Jubilee was the ultra modern state of the art new whiz kid machine- vastly superior in image to the Villiers two-strokes .

 

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