If it only happens between speeds IE: 40-60 or over a certain speed say over 80 or what ever i would say it's the balance. Take it to any tire shop & get them spin balanced. Should only cost $20 to $ 40 bucks & i bet that solves it
__________________
Gargoyle,, AkA-- Allen
92 SVX LS-L 80,^^^
90 Mazda B 2200 (the dog & boat towmobile) 226,^^^
03 Yamaha V-star custom /classic 3k