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reepicheep said:

Meanwhile, don't use copper gaskets on water cooled bikes, install the gasket (hopefully a good brand like Veserah) dry, and make the surfaces mirror clean and smooth before reassembly.

The best way I found to do cleaning is with bamboo kabobs from the grocery store... keep a big bag of them above the work bench, they are hard enough to clean all sorts of things well, but not hard enough to scratch aluminum, and the ends can be cut and shaped depending on the task at hand (flat like a screwdriver for scraping flat surfaces, sharpened like a pencil to get into tight crevices). Use that to get the "chunky" stuff off, gasket remover helps, but brake parts cleaner and wd-40 will work if you are patient.

Then take something like 1000 or 1600 grit paper (look at the auto parts store in the paint section) and put a clean sheet on the flattest surface you can find. At worst this is a clean piece of plywood or laminate, better is a plate of glass, best is the machined surface of your table saw. Spray some light oil on it, and lay the head and jug mating surfaces on it and move in circular motions until everything is shiny and clean... it'll look like a mirror surface.

Then bolt it up with a torque wrench, give it a heat cycle or two, and re-torque it if you want to be safe.

I learned all the hard way with a KLR-250 (overhead cam four stroke). It's one of the reasons I love my KDX-200 (two stroke). The KLR would leak if you didn't do the "heat cycle and re-torque" thing, which because it was overhead cam was a significant PITA. With the KDX, the head comes of easy, and in point of fact rarely has to come off at all... you can take the head off with the jug and leave that fussy little high pressure seal intact. The base gasket (because it sees only crank case pressure, not combustion chamber pressure) seems a lot less fussy.

So anyway, good luck with the search function ;)

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Brandon H. said:

Ok first I want to start off by saying that I like your idea, those little kabob sticks work wonders.

BUT

I think you have the whole lapping thing wrong. See I build computers, and one of the "mods" us overclockers do is lapping the heatsink and the CPU. The point of lapping is to get a perfectly flat finish, not a shiny one. I would only recommend lapping with a piece of glass, and not a piece of wood. 1000 grit and 1600 grit is pointless, all your doing is shining the object, and not actualy lapping it. These surfaces don't need to be shiny they just need to be flat, they actualy have to be a little on the rough side. I would go no higher then 600 to 800 grit. Take your time, and keep the sandpaper wet and clean is a MUST. 10 strokes back and forth, rotate 1/4 turn, 10 strokes back and forth, rotate 1/4 turn.....so on and so forth.

Time consuming yes, BUT you will have a VERY flat surface, which is what your after. I recommend taking apart the computer your typing on and trying it on the processor before the dirtbike, just so you have practice :laugh: :cool: . And watch those CPU temps drop by 10C

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whenfoxforks-ruled said:

A computer engineer by trade? Vintage Bob

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reepicheep said:

Its about getting a good sealing surface for the gasket... not really making the head flat. If the head isn't flat, you are already in trouble...

To be honest, its about getting all the old gasket off... if you have a mirror finish, the gasket is gone

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