Vintage Dirt Bike Q & A

I split my mt250 cases and installed all new bearings and seals. I need to know the best way to clean off the old gasket I am using a razor is there any other wai? I also need to know how to put the casses back together the book shows a tool that probably isnt available anymore so whats everyone do? I was going to gently tap it back together with a deadblow.

razor blade, goo gone and patience is what I now use to remove gaskets. I can generally hit the cases with the base of my palm or a rubber mallet until they are close enough together for the screws to catch. Then I go around in cross order to pull the cases together.

not that i have ever done this exact job but when i havde split cases before i would just use a razor blade like you are doing and scrape it off. also if you hold the razor at 90 degrees to the gasket surface you can kind of drag it across and remove little bits of material also. As for putting it back together, i would like them up and get all the aligning pins in line and such and pick strong spots to hit with your deal blow untill you can get the bolts to screw into the other side and suck it in that way by slowly turning each bolt in turn and doing that over and over untill it's sucked all together.

What works best for me is to use a broad blade gasket scraper. I find it doesn't have the tendency to "dig in" to the
soft aluminum like a razor. After scraping, I spray on some WD40, let it soak a while and then clean off the remaining
residue with my trusty scotchbrite (green) pad. You really want to get these surfaces clean and make sure there are
no cuts, scratches or gouges - all good places for air leaks to occur.

I'm guessing the tool you are talking about is a crankshaft installer/remover and you're right, Honda doesn't make it
anymore. The good news is a suitable replacement can be purchased from Rocky Mountain MC/ATV:
http://www.rockymountainatv.com/product ... lyId=17166

When you try to reassemble your cases, you have to insure two shift fork shafts, one shift drum, the main shaft, counter
shaft, crankshaft and at least two allignment dowels are all lining up correctly. Bashing your cases during this process
can cause uneccessary trauma to the internal mounting bosses and bearings - not good after all the hard work you've
done so far. The crank installer allows you to draw the case halves together in a slow controlled procedure while you
keep tabs on the allignment of all the internals. Once the cases are about 1/2" apart, thread the case screws in and
cinch them down in a criss cross pattern maintaining a consistent gap until sealed. One other tip I have found to be
useful is to use Permatex gasket adhesive spray. Spray it on the right case let it tack up then place the gasket in
position. In addition to holding the gasket in the correct location during reassembly, it provides additional insurance
against air leaks.

dogger

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1973 CR250M
1979 CR250R
1993 CR250R
2008 CR500R
2009 CR250R