Broken Case

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Barletta
Cucciolo - the Lil Pup
Posts: 8
Joined: Tue Sep 21, 2010 12:51 am
Location: Sydney Australia

Broken Case

Post by Barletta » Sun Nov 21, 2010 6:07 pm

Anyone ever had the joy :( of pulling their sprocket cover off and finding the casing broken where the bottom 8mm bolt threads into?
Looking for ideas for a repair without engaging the services of a welder. Thinking of adding a threaded rod to the case secured by liquid steel etc and then using a nut and sleeve on the outside to secure the cover.

rwhc80
750 GT
Posts: 174
Joined: Sat May 16, 2009 7:19 am
Location: Melbourne Australia

Post by rwhc80 » Sun Nov 21, 2010 8:01 pm

Barletta,

That would probably work, but be a little ugly, How badly broken is the threaded section ? will the 8 mm capscrew still grab some thread, or has it broken all the way ?

My thought being, that perhaps you can do a bit of filling with the liquid metal and re-tap the thread., as it's just one of the fixing points, not an oil sealed area.

Cheers
Rick
I have desmo disease, I just hope they never find a cure !!!

Barletta
Cucciolo - the Lil Pup
Posts: 8
Joined: Tue Sep 21, 2010 12:51 am
Location: Sydney Australia

Post by Barletta » Sun Nov 21, 2010 8:17 pm

Hi Rick,
Broken the entire length of the thread, top half has come away, only had the bike (GTS) for 2 months so not sure when or how done. Did try your suggestion however did not last long, pulled the thread out after a short ride. Without the bottom bolt the cover flexes when the clutch is applied...so a bit of force there.
You are right...my repair might be ugly but if i ride fast enought hopefully nobody will notice it. :-D

wdietz186
Cagiva Alazzura
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Joined: Sun Sep 10, 2006 5:40 pm

Post by wdietz186 » Mon Nov 22, 2010 4:54 pm

You could try using a stud set into the remaining threads and then bury it in something like JB Weld. I don't think the liquid metal stuff is as strong as a 2 part epoxy. To get a good bond you will need to clean it thoroughly and rough up the surrounding area so the epoxy has something to "tooth" into. Glue the stud into what is remaining of the threads too. It's a bodge but it will save a trip to the welders if you are lucky.
On the other hand,a good weldor could build up the area without too much trouble or disassembly and drilling and tapping a new hole isn't that difficult

BEVEL DAVE
Diana
Posts: 62
Joined: Sat Jun 13, 2009 7:22 pm
Location: SYDNEY, AUSTRALIA

Post by BEVEL DAVE » Tue Nov 30, 2010 9:56 pm

Why would you not want to weld it???

Where in Sydney are you??? I have a very good guy that would be able to do it no worries, I have had him weld cases that are smashed & broken before with little fuss or expense.

PM me for details as Im not allowed to post them.

Dave

Barletta
Cucciolo - the Lil Pup
Posts: 8
Joined: Tue Sep 21, 2010 12:51 am
Location: Sydney Australia

Post by Barletta » Fri Dec 03, 2010 12:51 am

hi all, thanks for the advice.
i actually fixed it by drilling further into the case about 1 inch and retapping. Then secured the cover using a longer bolt. it seams to be holding ok...time will tell.

jockduck
Mariana
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Joined: Sun Jan 17, 2010 3:21 am
Location: South Australia

Post by jockduck » Mon Dec 13, 2010 1:47 am

My GTS case had been welded on that curved bit that follows the sprocket and the grooves that the chain always makes and when I came to install the layshaft bearing I found the recess seriously oval!, Im sure a good welder can do a safe job but if I can find a way of fixing an alloy case without welding then its the way to go.
Jock

BEVEL DAVE
Diana
Posts: 62
Joined: Sat Jun 13, 2009 7:22 pm
Location: SYDNEY, AUSTRALIA

Post by BEVEL DAVE » Mon Dec 13, 2010 12:54 pm

Stuff like cases & heads need to be heated in an oven 1st, then kept at a constant temp for a while.
Once the welding is completed they need to be slowly cooled & you wont have these problems unless the welding is directly near the machined area concerned, it will probably need to be re-machined in that case.
If it is any type of structural repair welding is the only option if you want a proper result.

Dave.

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