Hi Albert
Its an early 83 model. Buzz and vibration are the same just a different word same meaning in the English language. The mechanic who services my bike has done many twin plug conversions and there has never been a problem with any of them. I have absolute faith in his work, people come to him from all over this country just to have him work on their bike! I bought the bike when It was one year old and it has always had this problem. In the early days I had it serviced at the local BMW dealer (Tom Byrne) in Sydney and they told me that there were a few others (1000ccmodels) that had a similar problem. After a few years Tom Byrne relocated and the old mechanic retired, and they seemed not to have any interest in the old boxers anymore so I switched to Don Wilson another well respected mechanical workshop with a history in racing R serise BMW,s they said the same thing, some R100's from around my bikes vintage had vibration problems due to crankshaft balance from the factory! I have done a lot of rallies over the years and as sutch spoken to many R100 owners some say their bikes are the same some dont, I can only assume that they ride below the rev range that this occurs. I did not really worry about it too much over the years myself because it only seems to happen once I go over 125 kmh I mostley travel at about 110-120kmh. It was only when I crossed the nullarbor between Adelaide and Perth a long straight road and sustaining a speed around 130-140 to stay with the group that it really anoyed me, if I went up past 140kmh it dissapeared completely, no vibration? I have had this bike for 24 years and I love it as much as the day I bought it. I can live with it until I get a complete engine rebuild and either get a new crank or get mine balanced, but with the amount of riding I get to do these days Ill probably die first!
Rob....