I had an RG500 aswell.I remeber when i bought it.I had read how quick they were but after my RD(one of 6 )i though geeeez this is slow compared to my RD.I changed the plugs but it was still the same.Then i thought i would try different coils.I fitted them and went wheelieing off down the road .It had only been fireing on 2 cylinders.Thats why it was so slow .I tryed to get an NS400R but the guy wouldnt do a deal with one of my RD's and i used to have the TDR aswell.That was a great bike for whizzing around town.Probably the first real super moto .