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Old 01-13-2012, 05:53 PM
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DaveC DaveC is offline
Motorized Bicycle Elite Member
Join Date: Jul 2010
Location: Boise, ID
Posts: 967
Default Re: what did you do to your motor bike today?

Well, using a sanding pad is a bad idea because what you end up with is two convex surfaces that your trying to seal. A pad sander has a tendency to round off the edges because theres nothing to support the pad so the edge of the pad will exert more pressure along the edge over removing material from the center because there's more pad to resist deforming. This tendency gets more pronounced the further from the boltholes you get. It will seal ok at first but the problem is insuffecent contact area for both heat transfer and to prevent walk. Walk is when the head squirms around under heat and can actually move quite a bit, mechanically speaking. Eventually you will get a loss of compression from leaking but.. if you re-torque every two tanks or so and do it cold you should be ok...

And just about any piece of glass will work. It doesn't have to be 1/2" bullet proof glass. I use a mirror. NAPA has packs of wet/dry sandpaper from like 220-400 and 600-1000 grit I think it is. That and some oil and follow a guide and you will be successful. You don't have to grind hard, the oiled wet/dry cuts very well. Just because you don't see huge results it's still working. I actually stop at 400 grit because I use Permatex Spray Copper Form-A-Gasket to help seal. I've used it in my race motors for years and have never had a gasket leak.

I also have lapped computer processors and heatsinks. You do need to do those up to 2000 grit so they take much longer to do than a head and jug in a HT motor
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