MCW
Somebody's talking crap here & it ain't the tree!
There is no major noticable power difference between the OEM 79cc top end and the 84cc BB top end. I've run both.
As far as people saying that there isn't a major difference in cutting speed between the two in smaller wood just lean heavily on both and you'll change your mind. The 79cc/84cc top ends will pump the 65cc top end. Just letting the saw self feed with gravity shows little difference.
I can say however that a number of the BB kits have shown pretty marginal, inconsistant quality and you never quite know what you're going to get until you open the box. Firstly, never, ever, trust the rings on an imported BB kit. Buy some Cabers alongside the kit. One thing I have noticed with the Chinese kits I've imported is a massive variation in ring quality. I've had to replace far too many BB kits while testing them and selling them to trust their rings anymore. Cabers only from now on and for 10 odd bucks a worthwhile investment. You'll also tend to see a compression increase with the Cabers across many kits - up to 15psi in the 372XP BB kits
As far as people saying that there isn't a major difference in cutting speed between the two in smaller wood just lean heavily on both and you'll change your mind. The 79cc/84cc top ends will pump the 65cc top end. Just letting the saw self feed with gravity shows little difference.
I can say however that a number of the BB kits have shown pretty marginal, inconsistant quality and you never quite know what you're going to get until you open the box. Firstly, never, ever, trust the rings on an imported BB kit. Buy some Cabers alongside the kit. One thing I have noticed with the Chinese kits I've imported is a massive variation in ring quality. I've had to replace far too many BB kits while testing them and selling them to trust their rings anymore. Cabers only from now on and for 10 odd bucks a worthwhile investment. You'll also tend to see a compression increase with the Cabers across many kits - up to 15psi in the 372XP BB kits