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Small crack in aluminium crankcase at cover mounting hole

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Nipedley
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PostPosted: 16:37 - 11 Feb 2018    Post subject: Small crack in aluminium crankcase at cover mounting hole Reply with quote

Hi guys. Just got a new bike recently and had an issue with the starter clutch, that's fixed now however I also discovered this (image below). A small crack above one of the mounting holes for the clutch cover (which has a broken bolt stuck in it drilled out to 4mm)

I've sanded it down and the cracks doesnt extend too far, what can I use to mend these? I don't think structural integrity is a massive problem, my concern more is oil weeping out. Would JB weld be appropriate to seal over the cracks?

Thanks!
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Pete.
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PostPosted: 16:54 - 11 Feb 2018    Post subject: Reply with quote

I would weld that up, and in the process remove that messed up bolt.
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MCN
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PostPosted: 17:02 - 11 Feb 2018    Post subject: Reply with quote

So it's not 'New' then.... Very Happy

The crack is as a result of come sunt dropping it and whatever was supported by the bolt levered the casting out from around the bolt.

It depends what is hanging from the bolt that goes in that hole.
If it is a foot rest or a brake linkage then I would want it.repaired by a substantial method. Aluminium Welding.

Our Bovine Proctologist has a recipe for home DIY Aluminium Welding. Thumbs Up

If it just holds something not too heavy then rough up the surface (keying) and stick a sizeable daub of plastic metal around the cracked bit.
Plastic metal is kinda-stucturally-weak so plan to cover.a bit of the case too. That gives the plastic metal more surface to adhere to.
And I.you use plastic metal then the surface must be completely dirt, filings, grease, oil and fingerprint free. The clearer tje.surface the better the bond.

JB Weld is not as good as some people say it is. It is very limited. It was probably good when there weren't many alternatives. Araldite do a plastic metal that is quite reasonable.
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Nipedley
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PostPosted: 17:48 - 11 Feb 2018    Post subject: Reply with quote

What kinda welding would be suitable? I don't have any experience or equipment for that but I guess a good shop would?

Nothing needs to be attached to it other than the clutch cover, so no worries on further stress. When you say plastic metal any specific products you'd recommend? It'll be immersed in the oil which is my main concern, though obviously I'd make it spotless for installation. I've got some araldite metal around here somewhere, JB weld and quiksteel. I heard loctite metal is good too?

Thanks for the replies Smile
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........
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PostPosted: 21:27 - 11 Feb 2018    Post subject: Reply with quote

Nipedley wrote:
What kinda welding would be suitable? I don't have any experience or equipment for that but I guess a good shop would?

Nothing needs to be attached to it other than the clutch cover, so no worries on further stress. When you say plastic metal any specific products you'd recommend? It'll be immersed in the oil which is my main concern, though obviously I'd make it spotless for installation. I've got some araldite metal around here somewhere, JB weld and quiksteel. I heard loctite metal is good too?

Thanks for the replies Smile


You need someone who can do AC TIG welding. They'll need to remove the remains of the bolt, clean up the hole, build up the casting the re-drill/tap. This is something that I can do. Where are you located?

To me it looks like someone has caused that damage in a failed attempt to drill/easyout the remains of a sheared bolt.
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Nipedley
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PostPosted: 09:47 - 12 Feb 2018    Post subject: Reply with quote

Any tips on how to find someone locally for that? I'm down in Cornwall, quite a ways from most people!
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Teflon-Mike
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PostPosted: 10:25 - 12 Feb 2018    Post subject: Reply with quote

"weld" by defanition is to join two pieces of the same metal, with molten metal of the same type, creating a 'seamless' joint across the artifact, in which the metal 'composition' doesn't change (much)

"Braze" is to join two pieces of metal, that needn't be the same metal, with another 'filler' metal, creating a joint across the artifact in which the metal composition changes.

Both processes are 'hot'and require the metal to be molten, ie made liquid. At least the 'filler'. With 'braze' the two parts of the artifact being joined, needn't be made hot enough to melt, but the filler metal does.

Solder? Is a specific type of 'brazing', in which the filler metal that gets made molten is an alloy of tin-lead, which has a peculiarly low melting point, and usually is used to join dissimilar metals, eg, the legs of electrical components, usually a tin/zinc alloy, to copper or copper alloy tracks of electronic PCB's.

GLUE... is a material that is in liquid form at room temperature, but on addition of a hardener or exposure to air, 'cures' to a solid state. Used like braze to join almost anything and anything, usually in a 'cold' process, where no heat is needed either to melt the metal or the 'filler' glue.....

JB weld is actually a glue. Metal-Set, is actually a glue.

Curiously, my electric glue gun.... heating up a nylon rod to melt into joints to stick-stuff together, is technically not 'glue' but 'non-metallic' braze?!?!?!?! Go figure!

There are a lot of anomalies in the subject, I have an 'Lumiweld' Aluminium 'Welding' kit. It uses a plumber's blow-torch, and a stick of high Zinc/Lead Aluminium alloy, to make a joint, which is technically brazing.. a lot of aluminium 'welding' is actually the same, because f you got the artifact hot enough to 'melt' and form a continuous 'joint'... you probably would't have an artifact! (I've actually done that using Lumiweld, TBH, on a cylinder head cooling fin! Dam fin melted before it took the filler rod!)

ANYWAY... none of this semantics is of much help to you...... So onto an answer that may......

OIL... things don't like to stick to oil.... that's why they stick it in engines and slosh it between moving parts.....

IF you have an oil-leak... there tends to be oil in and around the 'wound'. Whether you use a hot or cold or metallic or non metallic 'repair' to make the casing 'sound', it MUST be clean of oil, or whatever 'filler' you use just wont adhere.

In ether case, this generally begs that the engine be fully stripped, in order that the effected area can be cleaned and de-greased, and thoroughly dried so that filler WILL take to it.


Some, 'may' weld a built up engine, if the area around the wound is well enough cleaned, with solvents. Heat of the weld 'may' boil out any remaining solvent, possibly even bur off any small amount of residual oil..... BUT.. any carbon left from burning off will contaminate the weld, which is likely to weep or re-break, but more worry-some is that a built up engine teds to have a lot of paper or rubber seals in it.... usually in the same bit of metal you are deliberately getting rather 'hot'... they tend to burn or melt, and give you bigger problems to deal with than you had to start with!

A 'cold' process, like glue, can be more friendly on a built up engine and avoid melting or burning gaskets and 'stuff', BUT you tend to need t be far more diligent about the cleaning or the glue just doesn't adhere to the metal, as old oil and gunk gets in the joint. Spread the gloop over a wide enough area, though, you 'may' get enough of a 'patch' to adhere and form an oil tight joint.... question is for how long, as metal gets hot and expands and contracts at a different rate to the set-gloop.

You pays your money and takes your chances.....

But as already pointed out, looks like you have a 'mess' in that boss-hole, o old bolt/stud and stripped thread, as well as the cracked boss, A-N-D you have to get that 'fixed' and the gasket face for the cover that's going to bolt to it 'faced' flat so that will seal.

In short, it looks like a bit-of-a-buggah....

How valuable s the bike? How available/expensive are new or good used engine cases? How valuable is your time?

The 'inclination' here is for a bit of 'creative mechanics'... read 'a botch with CARE'... and a lot of cleaning, and preparation, to clean up the area around that boss, and get the old bolt/stud/thread out of it. Then any old oil residues, and probably finishing the 'break' of that cracked bit of boss, and re-making the whole boss area in metal-set or aluminium filings loaded epoxy (araldite), after scraping all the paint away from wound area, scarifying the whole area to give a 'key' on the metal for glue, and cleaning with very strong solvent, like MEK or at least methalated spirits. Giving that a day to dry, and then, rebuilding the boss in preferred gloop... another day or more to let that properly 'cure', and possibly even doing it in separate 'coats' to get necessary level and area of 'build' that can be filed to flat accross the casing gasket face, and very effin carefully drilled and tapped with a new thread for a bolt/stud.... which would probably beg the motor out of the frame and on the bench so it could be put under a pillar drill, NOT done in the half-dark with a wobbly bike on a side stand with an even more wobbly Hack-n-Wrecker hand drill! Which is a recipe for lots of snapped 2.5mm pilot drills, if you even bother to start with a pilot!..... Like I said... a botch with CARE.

Could be done... has been done.... more carefully its been done, the 'more' successful that has tended to be... which is often not very..... and done with enough care that it does work for more than a few weeks, its usually been cheaper and easier in the long run to replace case and rebuild.... you rarely save much money, even if you don't cost the time it takes to do the job... but not costing that can make it 'feel' satisfyingly 'cheap'..... until it leaks.....

Your call.... like I said, you pays your money and takes your chances.....
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Last edited by Teflon-Mike on 11:06 - 12 Feb 2018; edited 2 times in total
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Nipedley
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PostPosted: 11:04 - 12 Feb 2018    Post subject: Reply with quote

So getting the aluminium welded is the answer? Just need to find someone locally who can do that for me then Smile
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chris-red
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PostPosted: 11:39 - 12 Feb 2018    Post subject: Reply with quote

From what I have read on here you could use Silver solder to fix that fairly easily and cheaply.

Caveat: I know nothing first hand about it, but it is worth a look.
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raesewell
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PostPosted: 11:57 - 12 Feb 2018    Post subject: Reply with quote

Would Durafix EasyWeld do the job?
https://www.youtube.com/watch?v=n1njyuPBIH0

https://www.ebay.co.uk/sch/i.html?_from=R40&_trksid=m570.l1313&_nkw=Durafix&_sacat=0

Just an Idea. I used it recently on an aluminium bracket and it came out OK.
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bikenut
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PostPosted: 13:42 - 12 Feb 2018    Post subject: bit Reply with quote

Yep, looks like the remains of a sheared off bolt can be seen in the hole.

So, remove that first, but how, as the real damage has now been done, drilled off centre and the casing has cracked.

A blind hole ?

You could I suppose "bond" a 4mm stud in there and prey, using a nut and some sealer in that area to stop an oil leak ??

You could remove the "remains" and bond in a 6mm stud, and use a nut etc..

You could have it repaired properly but that would be relatively expensive.
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Nipedley
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PostPosted: 20:08 - 12 Feb 2018    Post subject: Reply with quote

Could this be welded without having to remove the engine and split the crankcase?

My thoughts would be to get it welded now if it can, if not then I will try and stem the leak for now until next Winter and then remove the engine and split the case and get it welded up at that point
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Pete.
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PostPosted: 20:23 - 12 Feb 2018    Post subject: Reply with quote

Nipedley wrote:
Could this be welded without having to remove the engine and split the crankcase?

My thoughts would be to get it welded now if it can, if not then I will try and stem the leak for now until next Winter and then remove the engine and split the case and get it welded up at that point


No problem welding it in situ. It's crowded slightly by that dome thing on the left but it could be welded no problem.
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........
Borekit Bruiser



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PostPosted: 15:14 - 15 Feb 2018    Post subject: Reply with quote

Pete. wrote:
Nipedley wrote:
Could this be welded without having to remove the engine and split the crankcase?

My thoughts would be to get it welded now if it can, if not then I will try and stem the leak for now until next Winter and then remove the engine and split the case and get it welded up at that point


No problem welding it in situ. It's crowded slightly by that dome thing on the left but it could be welded no problem.


I'm surprised by this comment. TIG is particularly susceptible to contamination issues. I would not even attempt to weld it with oil seeping through the cracked casing. Would you just weld it as is then?
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Nipedley
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PostPosted: 09:34 - 25 Feb 2018    Post subject: Reply with quote

Well I got her welded last week, looks good to me. After the pic I removed the remains of the sheared bolt, used some wet and dry to sand the sealing surface smooth and used some hylomar to try and get a good seal with the gasket. So far no leaks, so I'm a happy camper

Thanks for the suggestions
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Pete.
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PostPosted: 19:21 - 25 Feb 2018    Post subject: Reply with quote

garybee wrote:


I'm surprised by this comment. TIG is particularly susceptible to contamination issues. I would not even attempt to weld it with oil seeping through the cracked casing. Would you just weld it as is then?


You're right, it'd never work.

Oh dear - it seems to have worked!
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........
Borekit Bruiser



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PostPosted: 20:56 - 25 Feb 2018    Post subject: Reply with quote

Pete. wrote:
garybee wrote:


I'm surprised by this comment. TIG is particularly susceptible to contamination issues. I would not even attempt to weld it with oil seeping through the cracked casing. Would you just weld it as is then?


You're right, it'd never work.

Oh dear - it seems to have worked!


If you think that's a good repair and would be happy to let that leave your workshop then more fool you. As a bodge it's fine if a bodge is what the OP wanted. But that is in no way a repair that you could charge a fee for.

Do you TIG weld aluminium?
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Pete.
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PostPosted: 22:01 - 25 Feb 2018    Post subject: Reply with quote

No I said I would weld it up because I can't weld aluminium.
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mentalboy
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PostPosted: 01:27 - 26 Feb 2018    Post subject: Reply with quote

Pete. wrote:
No I said I would weld it up because I can't weld aluminium.


All things are possible with a flux capacitor, eh Pete? Wink
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ZRX61
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PostPosted: 00:29 - 01 Mar 2018    Post subject: Reply with quote

garybee wrote:
I'm surprised by this comment. TIG is particularly susceptible to contamination issues. I would not even attempt to weld it with oil seeping through the cracked casing. Would you just weld it as is then?


Welded up a hole in my ZRX cases. Just lent the bike over to the right, cleaned the area with lacquer thinner & tigged it. That was 12 years ago, no issues.
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MCN
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PostPosted: 19:07 - 01 Mar 2018    Post subject: Reply with quote

ZRX61 wrote:
garybee wrote:
I'm surprised by this comment. TIG is particularly susceptible to contamination issues. I would not even attempt to weld it with oil seeping through the cracked casing. Would you just weld it as is then?


Welded up a hole in my ZRX cases. Just lent the bike over to the right, cleaned the area with lacquer thinner & tigged it. That was 12 years ago, no issues.


Ahh. But a 'lacquer thinner wash' takes 13 and 1/2 months to fail. (Normally).

I agree the bodge is good. It doesn't look like the area has much more than hot oil to hold back and the cover bolts wont be much of a load. It will be 100% more robust than epoxy 'anything' and it probably will last longer than 13 and 1/2 years too.
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A100man
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PostPosted: 09:50 - 10 Mar 2018    Post subject: Reply with quote

Interesting thread. But a slightly frustrating end. I need to know:-
a) Was the original scrap of cracked boss left in situ? (presumably yes)
b) Did you get the old bolt out without cracking the repair?

J
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