French Newbie

Hi Everyone !

I've spent some time lurking and searching this forum, which I think as one of the liveliest about Nortons, and now that I have join the Nortonmaniacs community by buying my first Commando (850mk1/1973) I want to share with you.
To present myself,I am Xavier from South-West of France, and I began with Honda's (CB 350 and CB500Four) which are fairly good bikes, but I wanted to taste the britishness of a Norton, and I do not regret it !

Unfortunately, I had to open the primary drive chaincase to get rid of oil leaks. I decided to change the crankcase oil seal, discovered that the inner cover of the chaincase was cracked, so changed it, and now I see small cracks on the crankcase wall (on the pictures below) Should I worry about these ? My Commando is supposed to be only 14ksm, I think it's a little early to see signs of metal fatigue, what do you think ?






Thanks for your advices. I Hope I won't find any more horrors when servicing this engine, but I'm afraid a lot of sealant as been used as I found a good quantity in the sump filters (Some kinda red sludgy one), and I don't like that... :evil:

Good ride everyone !

Xavier

What you have there is the markings of a hammer monkey. Someone has had your engine apart and incorrectly replaced the main bearings.
And now you have damaged cases. I would wait for the collective mind to chime in, but my initial view don't look good.
If this is what can be seen on the outside, beware what is hidden. I don't want to be the bearer of bad news, but err on the side of caution.
Tear into it now before something inside goes bang and leaves a trail of parts. The peace of mind alone will be worth it.

Please continue to ask questions, we are all here to help and share our mistakes. we all have made some.

Bienvenue Xavier

You've come to the right place for all you Norton requirements.
Where are you in SW France ? I used to live near Bordeaux, Dept. 33.

A+

Webby

Hey Webby !

I live right in Bordeaux ! You know what it is : Lot of wine... Lot of rain :wink: But enough sunshine to ride the Norton !

See ya

Xavier

Hi and Welcome to the forum!

The crack on the boss in the top photo I could live with although you would need a crank case breather valve so it wouldn't spew oil out there. If that is a long radial crack in your second photo you need to worry. It looks like a result of a crank failure that was hammered down and jb welded or something. It should have been properly welded up before re-assembly. If it is a crack your cases would be a good candidate for the crankcase mod the 920 guys do to beef up their cases. There are photos of this mod on the forum but it is a lot of work and costly if you aren't going to racing or pushing your engine. The case halves are matched sets and new 850 cases (used on ebay) would be the cheapest fix at around $150.00 -$200.00. If that is not a 2" - 3" crack in the 2nd photo and the bike has been ridden for some time you likely have nothing to worry about other than the potential leak in photo 1.

I would say that somebody has tried removing the front sprocket with levers against the casing.
As for what to do, that is a difficult one.

YIKES! Well, either way you gotta get it apart to see it from inside and out to truly assess. Start shopping for appropriate cases, just in case. Ask about options as in maybe using 74's, finding a good half and such. PM LAB.

Ask about options as in maybe using 74's, finding a good half and such.

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Crankcases come in matched pairs. Replacing one half is asking for trouble. That's per Leo Goff, in case anyone questions this.

Moi...je ne me paniquerais pas trop si j'etais toi...Si ton moteur tourne bien attends qu'il casse pour tout ouvrir! Vu le model, ton arbre a cames doit etre entrain de s'user... alors roules et tu verras l'hiver prochain!
Philippe

Yes , some F Wit has been at it . BUT . Not all necesarilly doomladen .

If you regularrly attempt to blow of everything on the road and aspire to set records point to point , youll have to take it seriously .

IF its running SMOOTHLY , sweetly , no rumbles stutters or maladies and you seldom run past 5.000 rpm , Grin & bear it . BUT ,
Id grab a spare set of cases ( and whatever goes with them ) if you happen upon them at a sane price .Will Mk III cases swap .Thesere stronger .

First Photo , the radial ' crack ' down to the left from the oil seal ?? doesnt appear to go down the flange , surface scratch or crack .

Flo seems to have the other issue , the face , sussed . Dressing flat(ish :| ) Pliobond , the yukey heat proof glue , russo colour , is heat proofish . Was used by Kiwis will oil tight British Machines .

Cleaning the faces with solvent ( Acetone ) thorougly / repeatadly . Pre Coating both faces with pliobond , and giveing it a few days ( a week best ) before amitting OIL , could solve it for now .

This is pliobond as GASKET / Joint sealant .For a surface sealant a Two pack epoxie would be essential , & comprehensive degreasing . unhuuriedly .

850 cases are reputed to have progressively increased flange width , for sealing .
Breather Via timing cover usual update , plus other tricks .

If youre going to run the BolDor youll have to replace the cases . Dont freak out , have a good gander over the whole contraption to see if the gremlins have had other objectives also .
A darn good heave on G box mainshaft and similar inspection there , as to ascertain theres not a loose bearing , or the hammer in evedace thereabouts .

14.000 there shouldnt really be any blackening in evedance via rocker inspection .good time to apply levers ( cautiously on wood pads ) to check isolastic function , side play , & adjustment .
Feeler Guage in ' the works ' should make evedant a near even clearance circuferancially .

Hows the rest of it look , please . Pictures . Pictures . :mrgreen:

Actually , youd have to use Ayraldite or JB weld as its a non mateing face where the swines been at it with a cold chisel .
Zyglow dye penetrant / cleaner 7 Black Light for investigation . Biggles drills holes at the ends of the cracks , M-X style .

A good artizan Alloy Gas welder might treat it as a challenge . Can never have to many spares though .Three Bikes altogether may be adequate to cover the varying styles and tastes . :lol:

If its running WELL , two pot sealant for the meantime . If intercontinental Touring is the order of the day , A spare bottom end can be set up & swapped out leaveing you to reclaim full serviceability
on the origonal at youre liesure .

Yow know, I wouldn't freak out about it yet. Aren't those little cracks just at the oil seal and not the bearings?

As for the "tool marks", either a lot of sealant on that gasket or belt drive and run dry.

Let see the rest of the bike!

Hi guys,
Thanks for giving your thoughts on this !
I left the drive side uncovered, with its new oil seal, overnight, and I am pretty sure its dripping oil from the peripheral crack, suggesting it's quite a deep one (the seal staying dry).... :evil:
As the engine is running smoothly, and considering your advices, I thing I'll gather spares for next winter, in order to work properly at a good pace, and use my commando normaly this summer after a good use of sealant :lol: .

I'll post pics very soon :wink:

Xavier

prmurat said:

Moi...je ne me paniquerais pas trop si j'etais toi...Si ton moteur tourne bien attends qu'il casse pour tout ouvrir! Vu le model, ton arbre a cames doit etre entrain de s'user... alors roules et tu verras l'hiver prochain!
Philippe

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Salut Philippe, je fais une brêve incursion en français, mais que veux-tu dire par arbre à came qui s'use ? tu veux dire qu'il n'est pas traité comme celui des mk3 ? A+++ :wink:

Xpongebob said:

Hey Webby !

I live right in Bordeaux ! You know what it is : Lot of wine... Lot of rain :wink: But enough sunshine to ride the Norton !

See ya

Xavier

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Salut Xavier,

There's a lot more rain here dans le nord But the beers better
At least you have lots of good roads and the weather is good enough to ride about 10 months of the year.
I never did find many old bike specialists near Bordeaux, but there are more up here.
Here's a pic of my Bonneville taken last year at le Bassin d'arcachon.


Webby

I left the drive side uncovered, with its new oil seal, overnight, and I am pretty sure its dripping oil from the peripheral crack, suggesting it's quite a deep one (the seal staying dry)....

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Interesting........I think you have spotted my problem! I also have the same damage as in both your pictures and with normal riding I get some oil in the chaincase (belt drive). With hard use and a seal that has been in use for about 2000 miles that leakage increases. So, it is quite possible my leak is from that crack and not the seal as I always thought. I wonder how the damage occurred? The area of damage seems to be beyond the inner race diameter but less than the outside diameter of the outer race. That would exclude damage from the outer race being hammered into the case with too much force? Maybe from a bearing breaking up? I guess a temporary fix would be to degrease the crack as well as possible and apply a sealant, superglue, thin Loctite etc. Unlikely to work for long though.

I wonder if it would be possible to grind out the cracks, fill the area with weld and then remachine the area.
Maybe easier than replacing the crankcases.

Just a thought

Webby

Hi webby,

I LOVE the Bonneville, it's matching perfectly with Arcachon !
Your idea is good, but the problem is that the crack is about 1/4 of the diameter, so the crankcase is getting weaker on that area so a good weld would be needed and thus I should remove the crankcase for the operation.

Keith1069 said:

I left the drive side uncovered, with its new oil seal, overnight, and I am pretty sure its dripping oil from the peripheral crack, suggesting it's quite a deep one (the seal staying dry)....

Click to expand...

Interesting........I think you have spotted my problem! I also have the same damage as in both your pictures and with normal riding I get some oil in the chaincase (belt drive). With hard use and a seal that has been in use for about 2000 miles that leakage increases. So, it is quite possible my leak is from that crack and not the seal as I always thought. I wonder how the damage occurred? The area of damage seems to be beyond the inner race diameter but less than the outside diameter of the outer race. That would exclude damage from the outer race being hammered into the case with too much force? Maybe from a bearing breaking up? I guess a temporary fix would be to degrease the crack as well as possible and apply a sealant, superglue, thin Loctite etc. Unlikely to work for long though.

Click to expand...

I Least I was useful to someone ! :lol:
Hope you'll find a solution, as for me I don't have any clue about how it happened, as this is my first opening, and I have all the appropriate Norton Tools ! (I wanted to have everything perfect -I'm a kindda maniac with mechanic) :twisted:

See U

Xavier

If you are not worried about the strength of the case, then it should be fairly simple to seal that crack. Getting it really clean will be the hard part and might still require a tear down. On this kind of thing I tend to try the least destructive first and then progress up the chain as needed.

If you pulled the seal and heated the area well it will help drive the oil out of the crack, then as it is cooling you would need to flow something like acetone into the crack with a pipette. Since acetone is flamable make sure the case has cooled enough to lay your hand on, but the temp difference will help pull the fluid into the crack. Then the idea presented above about using some Loctite would be worth a try. I would warm the case again to apply it as it will open up the crack a bit.

If that doesn't seem aggresive enough, you could use a small cut off wheel and grind away some of the metal at the crack and work in some JB Weld or similar epoxy. There are a number of epoxy products that could be used to fair out the pry marks on the face as well if looking at them bothers you.

It is amazing how much stuff I have been able to repair over the years once I get to the point where I am going to throw it away if it doesn't work. I will leave the debate on whether the strength of the case is impaired beyond usefulness to those with more experience in the matter.

Russ

Xavier: mine is a MK 2 and here is the stock camshaft after 12000miles... So as you said you will certainly have to open the engine next winter!!


Philippe

:shock: OH MY GOD ! :shock:

What is this made of ? Pig Iron ? I've never seen such things on my +60Kkm Japs, are the tappets and pushrods so hard on camshafts ?

Xavier