Your Grandfather should have some tools especially the finned exhaust nut tool. Every Airhead rider has to start with getting this tool. Well almost every one. But you will use this tool again and again. So if Granddad doesn't have the tool there are several sources and thru the years there have been many versions of this tool. We will advise, but right now there is an original one on Ebay that has not been bid up yet. These go for a pretty penny sometimes. I don't want to tell you what it might be worth they are sometimes over priced I think. But I do like the original heavy BMW tool.