Don't do it. You'll notice that the centre hole in the Lockhart adapter plate is approx 25mm in dia, and the OEM Honda bolt is only 20mm dia.
The adapter plate needs a special threaded adapter to secure it onto the engine, the threaded adapter is internally threaded as well so that you can fasten the the oil filter canister to the oil cooler adapter.
If you just use a longer bolt like the CB750F2/F3 bolt, the oil will not be directed from the engine up to the cooler and back into the engine, but rather, it'll just flow around in that area and do nothing, so in essence, you'll have a "statue" of an oil cooler that does absolutely nothing. Here's a pic to illustrate my point. Cheers, Terry.
