Darmah Rear cylinder barrel cracked at oil casting line...

78ducati · Post by **78ducati** » Tue Jul 12, 2011 9:01 am

Looks like some repair was done on the rear cylinder some time ago but wasn't welded right since cleaning of the oil inside cylinder wasn't done properly, creating oil to mix with the weld, and there you go... what is the best way to repair this sort of thing, its not the bore so I'm good, but oil keeps leaking out as I ride... JB weld? Hot temp gasket seal? any good bond out there??? I'm trying not to get the cylinder out of the bike and just do a temp bondage repair for this season...

here are some pix

cylinder_crack1 by 78ducati, on Flickr

cylinder_crack2 by 78ducati, on Flickr

cylinder_crack3 by 78ducati, on Flickr

Ray O'Donohue · Post by **Ray O'Donohue** » Tue Jul 12, 2011 9:33 am

How about cleaning thoroughly,then brushing/painting an aluminum epoxy into the fault? Also,light peening with a blunted pin punch sometimes helps,but it loks like a bad idea in this case-might make it as lot worse.

78ducati · Post by **78ducati** » Tue Jul 12, 2011 9:57 am

Ummmm, there is at least 80psi of oil pressure in there, we need something more substantial to hold up in fairly good heat expansion... welding it back will be ideal but not the option for this season...

what epoxy paint you had in mind???

Cheers ;-)

Ray O'Donohue · Post by **Ray O'Donohue** » Tue Jul 12, 2011 10:03 am

Not paint,but aluminum-epoxy,"painted in" with a brush,maybe in more than one layer. JB-Weld,I think had or has an aluminum version.

Ray O'Donohue · Post by **Ray O'Donohue** » Tue Jul 12, 2011 10:21 am

http://www.amazon.com/ALUMFAST-H-55-5-M ... rid_pt_0_0 Might work fine for years! Or,maybe not,what with expansion/contraction.

78ducati · Post by **78ducati** » Tue Jul 12, 2011 10:52 pm

I just mixed JB weld with reinforced aluminum shaving I took off some scrap aluminum pipe.... will find out how it holds this weekend...

Cheers

mizike77 · Post by **mizike77** » Wed Jul 13, 2011 1:39 am

Isnt that just a poor casting? Shouldnt a blemish in that area be non oil filled and non compression affecting? The cast iron sleeve is pressed in there and a crack there should have no affect on anything....unless its exactly at the oil galley.

78ducati · Post by **78ducati** » Wed Jul 13, 2011 9:19 am

Yup, looks like a bad casting from the start, oil gallery is right where the crack is ;-(

it does not affect anything, but oil pours out of there when engine is running...

Cheers....

machten · Post by **machten** » Thu Jul 14, 2011 6:38 am

I'm not sure about barrel temps on the outside of an oil gallery, but I've used Devcon to deal with crankcase porosity on a roundcase, and it has been absolutely brilliant with no issues for several years.

As with any other solution, you'll need to make sure you don't choke off the oil gallery by forcing it in too far. I'm not familiar with JB Weld other than seeing the name around a lot. If it has the same expansion coeffiecients as the the alloy and can handle the temperature, then it should be fine. If not, then it will part company with the parent metal at some stage.I'm not sure adding shavings of ali helps your objective. I think it's likely you've introduced too different and coarse expansion coefficients into the equation.

This Devcon stuff is the business. If the temp is under 250F, I'd use it for sure for your application. The added benefit is that if you finish it off well (with water), it will be close to invisible.

http://www.devcon.com/prodfiles/pdfs/fam_tds_107.pdf

Kev

Eldert · Post by **Eldert** » Thu Jul 14, 2011 2:17 pm

for repairs like that i use Manley 40180 miracle seal epoxy

they claim it can withstand temps up to 1350 F

Eldert

78ducati · Post by **78ducati** » Fri Jul 15, 2011 8:17 am

Thank you all, all those epoxies sound amazing, I guess new technology has brought adhesive to a new level....

I would The Devcon aluminum putty for cosmetic repair like bad welding etc.

and the Manley 40180 miracle seal for welding like repair, you think I can reattach broken cylinder fins with it???