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Navigator test ride after second engine rebuild

Submitted by ulrich_hoffmann on Fri, 02/10/2020
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Light Twins

I finally found some time to complete my Navigator engine after the second engine seizure. Last Wednesday was a nice sunny autumn day so I took the Navigator for a test ride. I checked my ignition timing again and used a strobo lamp to find out my "accurate" marks for the timing where not so correct.. Now the Boyer ignition is set to 24° before TDC.

The bike ran fine and I did not exceed 40-50 mph. I let it run smoothly without stressing the engine. After 10 miles or so the clutch was getting  sloppy and gearchange was more difficult so I returned to my workshop.

Here you see the bike after the ride still with the "interim" front mudguard from an early Commando. The original fender is at the paint shop again after the paint flaked off because it was a chromed mudguard and the paint did not stick too well to it. No second try with sandblasted fender.

Engine is surprisingly oil tight, also no oil weeping out the gearbox. Unfortunatly the kickstart return spring is a little on the loose side because I did not take care of the right position of the kickstart shaft while assembling the gearbox.

​Navi after testride

The reason for the slopply clutch was a loose center nut on the clutch basket so the whole assembly moved outwards. I tightened the nut the next morning and have to find a new gasket for the primary cover. Ther must be one in my gaskets folder somewhere...

Open primary drive

 

 

Submitted by robert_tuck on Fri, 02/10/2020

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Well done Ulrich,  Your determination is impressive. You must put the bad experience behind you ,if you are to enjoy the fruits of your labour.  Not easy to do .  

Submitted by dan_field on Fri, 02/10/2020

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Well done Uli, I hope this build is successful! Don’t worry about the clutch nut, it’s a common problem, I made a locking tool out of two clutch plates and a handle and also used loctite, hopefully it will hold! 

Dan

Submitted by andy_sochanik on Sat, 03/10/2020

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Hi Uli,

Nice picture - congratulations on completing your restortion (well, almost complete....).

Sadly, on the 1961-63 gearbox, it has been known for the clutch nut to come undone, due to an oversight at the factory. When I examine how the clutch is bolted up to the mainshaft, there is no shoulder to act against when tightening. Initial '58 Jubilee mainshaft was stepped down to receive the clutch, but this was deemed to be a weak point and was eliminated for the Navigator.

As a result, over may miles (Kilometers), the splines may show some wear after accelerating/decelerating and the clutch may start to rock back and forth slightly on the mainshaft, thus gradually loosening the nut.

Solution is to use Loctite at the very least - and better still - if there is room, run a locking nut down on top of the original nut. Sadly, no Nyloc nut of that size exists (unless someone knows better).

Good luck

Submitted by george_farenden on Sat, 03/10/2020

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Middleton's,  the stainless people used to offer bespoke nylocs. Have no idea if they still do or whether there is a minimum order quantity, but may be worth the ask? New spares items request?

Just a thought. 

Uli. Like others,  your restoration is well done and I admire your persistence with the teething problems. 

Regards, George. 

Submitted by ulrich_hoffmann on Sat, 03/10/2020

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Thank you for your comments!

Thanks Andy for the clutch nut information What thread size is the clutch nut? I will try to find a locknut. Plan B is as long as the primary drive is open I will dismantle the clutch once more to put some loctite on that nut.

I made some other improvements to the engine. A new breather was fitted behind the left hand cylinder with a one way valve from a Mercedes ( or OPEL?) engine of the size of a fuel filter.

Also a six-start oil pump was fitted to improve oil circulation.

Next task is the fitting of a side stand like mentioned in another thread in this forum.

The bike is hard to get on the mainstand. Some material was welded to the lugs on the frame so the bike now has the rear wheel off the ground when lifted on the stand.

And yes Robert, I put the bad expiriences behind and look forward to drive the bike.

After the Navigator test ride I took my 1970 Commando for a spin. Also ran fine and no oil leaks.

What is wrong here? LOL

Uli

 

Submitted by robert_tuck on Sat, 03/10/2020

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Hi.  It sounds like the clutch  /shaft detail  is poor,very much like the one on the Dommy. And recently discussed on the heavy twins  forum.  Something which may help with reliability is to make sure that the washer under the clutch nut is a very close fit to the shaft and the spider recess so it can give the most support to the stop detail in the spider.    PS, yes I do have a spider phobia ,they really give me the creeps !.

Submitted by john_holmes on Sat, 03/10/2020

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When you fit a gasket use sealer on one side and grease on the other, the grease will allow the gasket to stay on the surface its sealed to intact on disassembly but will still seal on 2nd or 3rd use. Ideal for primary covers were extra access visits are needed.

Submitted by ulrich_hoffmann on Mon, 26/10/2020

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Hello Dennis!

Thanks for your comment. Yes, the bagdes are not perfect, some deeper pitting could not be removed but far better than before.

Now the "almost" last piece is here. The front mudguard was apinted new because the paint lifted because it was a chromed fender and the sanding before painting was not enough to get the paint sticking to the metal. I had the mudguard sandblasted with coarse grit and my paintshop again made a magnificient job.

Navifrontfender

 

Mudguard is now on the bike.

Now I am tinkering with a Kawasaki side stand as mentioned in another thread. My plan is to draw an altered mounting plate to fit the Navigator frame with an option for a microswitch which will interrupt the ignition when the stand is out. German MOT wants that feature or alternativly a selfretracting spring on the stand. The drawing will be converted into a dfx file for lasercutting the plate.

Will report!

Uli

Submitted by nicholas_clarke on Mon, 26/10/2020

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Great to hear all the good news after so many problems Uli ,and see what a fantastic job you have done with the Navigator!   You have much sage advice over how to solve the typical clutch retaining nut problem - for what it's worth I gave up using the fiddly primary chain case gasket which seems to only be obtainable as part of the full gasket set.  I use silicone sealant which is easy to use and seals it every time!    Good luck with the running in process - patience and meticulous attention to re-torqueing the cylinder head should ensure it remain oil and gas tight and settles down to be a reliable, well handling and stopping, surprisingly brisk and charming bike!  Looking forward to hearing how it goes and seeing more pictures!

Cheers   Nick

 



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