Had a go at adjusting the chain on my 1986 Honda GB400 for the first time today. I'm pretty much a noob when it comes to mechanical work, but they showed me how to do this at the place I bought it. Anyway, no problems, until I was tightening up the hex nut on the right rear chain adjuster bolt. The hex nut just seemed to spin in place and not tighten. I took the whole bolt out and it seems to be stripped, but just around where the hex nut is. I've put it back on and managed to move the nut somewhat on to where the thread is, but I can't really tighten it properly without it going back to the stripped part of the bolt. The chain is fine now (it was a bit loose, that's why I adjusted it in the first place) and I've put everything else back to how it should be. Would the bike be safe to ride with that hex nut not done up as tight as it should be?