My stupid idea of the week (fixing busted cooling fins)

[Skier]

So, in my Rad's earlier life, someone dumped it pretty hard at least once. Because of this, there are a couple cooling fins broken off on the engine. Looks to be on the cylinder head. Nothing too big missing but it sure don't look right. We're tlaking maybe 1/2" tall by 1" long section or two.

Now, my stupid idea: using some wooden forms with wax paper and making the fins with JB Weld. I haven't used JB Weld too much so I'm not sure how strong it is nor hot it handles heat changes like my air-cooled engine would put it through. Any thoughts on doing this? I figure the worst that can happen is the JB Weld eventually cracks off from too many heating/cooling cycles and at best it's an acceptable replacement.

[oldnslo]

You might create a "hot spot." The fins are aluminum, JB is an epoxy amalgum with metallic particles. No idea how it would work. The correct fix would be forming and welding an aluminum piece to fit and grinding to fill in.
Maybe somebody else here has tried it with success.

[BuzZz]

I've used it on engine blocks before, but never on an air-cooled motor like your thinking. It will take the heat of normal use, but the heating/cooling cycles could indeed mess with you down the road. It won't provide any cooling effect for your head, so it will be cosmetic only.

[Skier]

Well then. I already have plenty of cosmetic effects with a leaky valve cover gasket and evidence of drops in the Rad's previous life, so I won't worry about it! Thanks for the advice, guys.

[oldnslo]

Maybe you could add some of those bullet-hole decals......

[BuzZz]

Maybe you could add some of those bullet-hole decals......

Those are DECALS??? No wonder my tank leaks......

[Quick 350]

I used JB weld to make up for a few cracked cooling fins it defiantly made the bike look better but I don't believe it helped any in heat dissipating.

How long did it last? I did it over 4 years ago and about 20K miles and it's held up (70 CB 750) I painted the cylinder jugs red after so it looked realy nice I wish the paint held up as good" the paint is still on the JB weld though"

[Quick 350]

I used JB weld to make up for a few cracked cooling fins it defiantly made the bike look better but I don't believe it helped any in heat dissipating.

How long did it last? I did it over 4 years ago and about 20K miles and it's held up (70 CB 750) I painted the cylinder jugs red after so it looked realy nice I wish the paint held up as good" the paint is still on the JB weld though"

[oldnslo]

JB will fix almost anything, at least strength-wise and cosmetically. A cooling fin repair may create a temperature differential, due to heat dissipation differences in non-similar materials, but probably not enough to hurt anything.

[arcaneman]

So, in my Rad's earlier life, someone dumped it pretty hard at least once. Because of this, there are a couple cooling fins broken off on the engine. Looks to be on the cylinder head. Nothing too big missing but it sure don't look right. We're tlaking maybe 1/2" tall by 1" long section or two.

Now, my stupid idea: using some wooden forms with wax paper and making the fins with JB Weld. I haven't used JB Weld too much so I'm not sure how strong it is nor hot it handles heat changes like my air-cooled engine would put it through. Any thoughts on doing this? I figure the worst that can happen is the JB Weld eventually cracks off from too many heating/cooling cycles and at best it's an acceptable replacement.

Hi Just chip my fins on my CB750K K4, not big enough to effect cooling but the bike is near perfect and bugs hell out of me! Did this idea work? Thanks Mike