Hello,
56KHK.
I recently bought this bike and have been going through it (oil changes, timing, rear chain replacement, brake adjustments, painting the jugs, ....).
In reading the 'Rider's Hand Book' which came with the bike (although I am not at all sure it is for my 1956 bike), I see where there is a transmission oil drain plug and a transmission oil level plug.
I see those parts in my parts manual (34745-52, 6218W and 3720) but my parts manual does not show the description of what those parts are for some reason. According to my Rider's Hand Book, I am supposed to remove the drain plug (34725-52), drain all the oil, put the drain plug back in, then remove the oil level plug (3720), remove the oil plug on the primary cover, fill it up with oil (about 1.5 pints) until oil drains out of the transmission oil level plug, then put that plug back in as well as the primary oil plug and all is well with the world.
I can see from the picture in the parts manual that the oil level plug sticks up into the tranny (by how much I do not know) and I would assume that it is hollow. The intent being that when the oil level is too full, it will drain out until it becomes just right.
Anyway, on my bike all I have is a single plug on the bottom of my tranny, like the plug that you use to drain oil from the crankcase. There is no tranny oil level plug. Not sure if there is supposed to be one for a 1956 bike. Is there?
Regardless, since I do not have a tranny oil level plug and cannot find one anywhere via google, is there is some easy way to check the oil level in the tranny? If not, would it be reasonable to just drain the tranny with the plug out for an hour or so to get every last drop out, then put the plug back in and add 1.5 pints through the primary plug?
Is there any danger to overfilling the tranny?