removal of the primary transmission cover


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The alloy would pinch under the head nuts stress.

I've never had that problem with the primary cover. Maybe you're doing the bolts up too tight Vince. Or if you're not using flat washers under the bolt heads it would be more likely to deform the edge of the holes.

I just give the cover a tap with a rubber mallet to crack the gasket seal and it comes off OK.


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It's the head only with this issue in the past Cam, hopefully, fixed with tidying up the holes and some as big as possible hardened washers under the nuts. it gets old doing the 10,000 little hits with a soft hammer. Happily, not me but I get to watch.


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Having a lathe on hand, made suitable increased thickness under nut washers, head nuts. Know well what you describe Vince, head clearance holes around the crank case studs, deformation. Sure Red has a trick or two up his considerable sleeves, you become good at these pesky obstacles when working on older motors.

Cam, you have done well on primary cover on and off's, had some toughies come through the workshops of mine in the past. Good quality gaskets are a blessing, in sealing and staying intact for replacement. Seen some poor ( new even ) primaries that could not be sealed from oil leaks at all. Usually post welding and deformation of the edge consistency, machining the edge solves one problem and introduces worse ones, my experience of course. j


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sometimes they can be a bitch to get off, its mainly because the cover has no location dowels, nor does the inner gearbox cover, for me that is a bit of manufacturers cheapskatedness. the two needle rollers in the case tend to "hang on" especially when not square, and always take out the adjuster bolt completely (also drains the pri chaincase oil)

I always grease both sides of the gasket, makes removal a lot easier (no gasket stick) and then the gasket can go again, very handy if you get trouble away from base, e.g. broken twin simplex chains.



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Cleaning old gaskets from Honda Four motors back in the 70s was a true nightmare - we had a couple that we ended up sending away to have them milled off. There may have been a trick to it, but we didn't have time as a professional workshop to charge people hours to remove gasket material.