I was recently replacing the top bolt on the front fork of my 1975 Honda CB550K. The old one was pretty rusty, and I was replacing it with a new one. I ordered the part offwww.shspowersports.com and it is the correct OEM part. Problem is that the one I took off is threaded on the bottom/inside, and the one I ordered is hollow there. On the old one, there is a rod that runs down through the spring, and connects the top bolt with a nut/cap/piece that threads right into the bolt. With the replacement part, it is impossible to thread it in, as it is hollow.
I called the parts guy at SHS and he thinks someone might have put in a different type of spring years ago…but that is curious to me, because it threads perfectly into what seems to be the correct top bolt.
Any idea what I have going on here, and what the solution might be if I want to replace that rusty top fork bolt?The bolt is seen here on the schematic as #37, but I don’t think I see the rod there. Also attached is a picture of the replacement bolt.
I don’t think I’ve ever seen a fork cap bolt that was threaded on the inside. They normally just pop right off and are smooth on the inside like the ones you are holding in the photos.
I’m trying to remember the last set of CB forks I pulled apart. They definitely did not have an interior thread, I’ve never seen that, but they might have had a special washer on the top of the road which sits against the face of the cap (preventing the rod from sitting all the way into the hollow hole).
I would think you’re OK as is, but I’ll do a little searching and see what I can find. I’ll try and locate some of my photos from a recent fork disassembly.