Weak links

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Commando Head stud thread..

https://www.accessnorton.com/NortonCommando/commando-head-stud-thread-2016.20892/#post-311789
The 20 pitch thread is a poor choice in an aluminum head. The 20 pitch helicoil insert is only slightly better. The fine thread just does not have enough strength in aluminum.

The best repair short of sending your head for the custom bronze inserts is to use a 3/8-16 helicoil and a custom stud. the coarse thread is much stronger.
You can take an old head bolt and cut it off slightly longer than the original stud and use a dye to cut a 3/8th- 16 thread on the end. This works pretty well as a custom stud. Jim
https://www.accessnorton.com/NortonCommando/commando-head-stud-thread-2016.20892/#post-311790
The 3/8" BSF thread can be a problem even on new heads. My very expensive Fullauto head suffered the same fate. I machined up three inserts 1/2" x 16 BSF outside & 3/8" x 20 BSF inside & screwed these into the head using high temp. Loctite, much the same as Jim does. This should hopefully fix the problem for good.

https://www.accessnorton.com/NortonCommando/commando-head-stud-thread-2016.20892/#post-311791
I got to the point several years ago that I don't even install a head unless it has inserts -new or old.

Nothing like that sinking feeling you get when your finishing up an engine build and the head stud just keeps on turning. Or your out on the road and oil starts blowing out of the breather because combustion is finding it's way into the pushrod tunnel.
 
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Cracked RH4

https://www.accessnorton.com/NortonCommando/cracked-rh4.18564/page-2#post-276819
Well, you can add me to the cracked RH4 group. I just checked the head on the MK3 that I'm rebuilding, and discovered the dreaded crack at one of the intake guides. Its visible without the need for dye penetrant checking. It looks about 3/8" long, but might be longer if checked properly. Supposedly, the bike had around 20,000 miles when it was torn down and put in boxes, which is how I got it. The other port doesn't show any cracks to the naked eye, and it didn't seem worth it to do the dye penetrant check. Fortunately I have an RH10 head off a race bike that looks pretty good, other than needing exhaust thread repair and stud inserts. More work for comnoz. I have another MK3 that I'm about to tear apart, hoping that the head is ok. Sure would be nice to find a method to repair these heads. Must be a lot of them out there by now. I would consider trying to weld it, but I haven't had really good luck trying to weld on Commando heads, other than for fin repairs. The castings tend to be really porous, and you can never seem to get all the oil out. Those Fullauto heads are looking better and better to me.

Ken
https://www.accessnorton.com/NortonCommando/cracked-rh4.18564/page-2#post-276822
I find the topic of a cracked R4 head depressing. As I read the posts it appears that there is really no fix which is considered "best practice" and permanent other that a Fullauto head of course.

If this is true, I would have to pay over half of the market value of my bike for a permanent fix, and the probability of it happening is fairly high.

Depressing.
https://www.accessnorton.com/NortonCommando/cracked-rh4.18564/page-2#post-276823
If the head was not cracked when the guides were installed at the factory -then the likely-hood of it cracking at a later date is pretty small -unless someone does a poor job of fitting new guides when rebuilding. Jim
 

Fast Eddie

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Gents,

This thread rapidly turned into something way outside of my intended scope!

Authoring / moderating / administrating something of this nature is way outside my ability and, frankly, level of interest.

So, as they like to say in Dragons Den; “I’m out”.

If anyone else wishes to pick up the baton, please feel free...
 

SteveA

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Not sure who is plotting, or whose heart is being blessed, and this is sorta uncomfortable, like calling out your friend's faults, but to the original post, we might add:

Fractured oil tank bottom fittings
Chain oilers that "over-performed"
Mediocre non-serviceable rear shocks
Oddly designed front forks
Marginal charging system
Dim headlamp
Poorly plated spokes
Weak front brakes
Swingarm spindle problems
Carelessly placed timing marks
Air filter that scraped off frame paint with every service attempt
And how cd I have almost forgotten the bloody speedo drive!


I love my bike, and I'm pleased to address most of these "issues".
Each person would have his own list, I would not argue with Fast Eddie's or yours......but...... some of the comments are made with reference to modern standards, not those prevalent in 1969/70.....

For example, your 'Mediocre non-serviceable rear shocks' were industry standard and better than those fitted to the Japanese competition at the time! And you didn't really need to service them when new ones were readily available and economic.

Similarly whilst I may recognise the limitations of Roadholders in comparison to my current Maxton cartridge forks, in 1975 even, the whole suspension was more than capable of winning a Production race and regularly did!
 
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[QUOTE="SteveA, post: 375240, member: 3746

For example, your 'Mediocre non-serviceable rear shocks' were industry standard and better than those fitted to the Japanese competition at the time! And you didn't really need to service them when new ones were readily available and economic.
[/QUOTE]

Indeed the Girlings fitted to my Commando are still in use on my ES2
 

Mr. Rick

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Steve, Mike: Yes, I certainly was using "modern-day" standards with reference to "weak links" in the overall sense.
The Girling rear shocks were prob okay for the period, but I have the impression (and no first-hand knowledge or experience) that the Koni units, as fitted to the Guzzi of the same period, were regarded as much better. Is that not correct?
 
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Well I have Konis on mine ,but hand on heart I cannot say they are any better than the Girlings were when new. A source of some dispointment ,for the engine gearbox swinging arm unit connects to the frame through the suspension legs . Konis do seem more substantial but it didnt seem to make any difference. Could be wrong but Konis were not available in the UK when the Commando was launched.
 

SteveA

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I think Konis were available for Nortons in the '70s, but retail they were expensive compared to Girling. I 'uprated' Girlings by going to Girling Gas, yes an improvement, but more overall because I chose longer units for my Rickman!. We didn't feel there was much in it, but if I recall well Koni were always rebuildable. Most Commando based racers were on Girlings then, easily bought from a Norton dealer or aftermarket supplier.

And of course the pricing to Norton of a locally manufactured item in volume, compared to an imported item probably with less discounting would have made the choice very easy.

Guzzi could have chosen an Italian product, I guess I am somewhat surprised they didn't, but a Guzzi sold at a significant premium over a Commando in the UK in the '70s!
 
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The Koni 76 series have adjustable rebound damping but you have to remove the spring to adjust, the 7610 series have the rebound adjuster on the dial at the top. Until you adjust the rebound to suit they will be no different to a Girling.
 
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