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By stinkwheel
#76132
Epoxy is certainly a good option but I'd personally pick JB weld over araldite. I've seen holed crankcases and stripped drain plugs repaired with JB weld. It's a thickened epoxy and metal coloured.



Another option is you could thicken the araldite by adding some aluminium powder, this will make it a better colour match, less likely to run (more like applying tile grout than a runny adhesive) and more resistant to degradation in sunlight. You need a surprisingly small ratio of epoxy to thickener. Aim for a consistancy similar to peanut butter. It may, perversely, help to open out that area of damage slightly with a small burr so you have more surface area to fill. If it's full thickness, drill a small hole at the "point" of the crack to prevent it actuang as a stress riser and propogating further



Another option is to use a low temperature aluminium solder like lumiweld or durafix. You'll need a good source of heat for a casing like that, a blowlamp wont do it. If you haven't used such stuff before, practice on some scrap first so you don't just blow holes in it. Lots of videos on youtube on its use.
By Alan R
#76136
Hi Guys------I agree with Stinkwheel re}---JB Weld........It really does set like metal and can be filed, turned, drilled and tapped in just the same way.....Recently I had to repair one of my glass-fibre bodied locomotives where a 5BA threaded handrail stanchion had been accidentally wrenched out of place by a "Certain person"---koff, koff !! ( is that the time ??)...............The hole was enlarged and a plug of JB Weld made up and fitted...........next day it was tapped and the handrail assy. re-fitted !!ImageIt's the front grab rail and left hand stanchion
By Lord-Toady
#76146
I think I am going to get some JB Weld looks like good stuff.

Mark, what size beading did you use to replace the stock oring? I halve measures my old one with calipers and it is 6mm diameter would 8mm be the size to go for or 7mm? I am going to put the join right at the top of the case and cut diagonal.
By Mark M
#76147
As it happens the stuff I bought was 6mm but it seemed more solid, maybe I'm imagining it! The reason I sourced it separately was that it was for the early type chaincase and there wasn't a continuous seal available. JB weld is excellent stuff, I also use it but I mentioned Araldite as a quick fix to get you on the road and now the others have come over all 'engineer' on me!

REgards, Mark
By Lord-Toady
#76150
I may have found an easier fix for the leaking plug hole, the saw mark doesnt seem to go that deep and just touches the edges and the sealing face looks ok inside. I have tried replacing the red fibre washer with a copper washer from a brake banjo bolt and it seems to be sealing better.

Incidentally I noticed a bit of engine oil leaking from around the head and checked my oil pipe banjo bolts and they were a bit loose, the front one was very loose and I was noticing some oil splatters when revving the bike on the drive. I have now tightened them, it looks like there was a bit of a leak from the decomp valve but that might just be oil running across from the front pipe connection.
By Lord-Toady
#76153
Right that didnt work and now I think I have found and hopefully fixed it.

The previous owners plug was a cut down 8mm bolt but the head was too big too fit properly! I have cut down an 8mm stainless button head bolt that does fit and fitted it with the original washer. You can see the mark where the old bolt was tightening down to the outside of the lip and not the mating surface.


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