Forum

[ChrisD]

Guys
I have had my 1996 535cc Classic engine balanced to a 62% factor after Egli’s comments in the BritBike magazine of Oct1994 (that number being about midway between many other suggestions ranging 58-70%). Already the engine feels MUCH smoother; easily and comfortably revving at 5100rpm. I am sure it will rev higher comfortably too (the steel conrod now gives me a safety margin for that) but having retimed my Hitchcocks performance cams to better match Redditch (using a dial gauge, see below) I still have to rejet the carb (32mm Amal Mk2). So balance factor is indeed critical to comfort – the bike hasn’t felt this good since new. Whatever the crank was balanced at in the factory was nowhere near as good as it is now.
Cheers, ChrisD
PS: I hope the picture appears, if not see Chrisd200 in photobucket.

[scotty]

Hi Chris my 93 bullet was balanced to 63% very good now from new half an hour your fingers were numb newuce very bad on vibrations other one ridden for 2 days even worse, factory needs to learn how to balance cranks, mine was done on a balancing machine while pulled completely apart then assembled and trued up.get a lot of crap saying vibes will go after a few thousand klm if it dont shake its self to bits.my old speed twin was turbine smooth compared to indian bikes.

[ChrisD]

Scotty, yes in retrospect, and having measured only a dirty OEM piston etc plus the OEM conrod, the factory balance factor must have been 66-67% (about as Egli said, way back then) - and it was as rough as a piece of old rope at anything over 3500rpm. Knowing the weights of piston etc, the difference between 66% and 62% for that setup would only have been about 25grm. What a difference a small change could have made if they’d set it up right.

With my current setup (steel conrod to replace the 20thou stretched OEM rod and with Hitchcocks 535cc) before re-balancing, the factor would have been is just 56% - and that was awful and destructive (inter alia it bent the drive shaft threads as the rotor tried to shake itself off). Removing about 45grms from the flywheels made all the difference and it is now at 62%. To be able to accelerate through the gears exceeding 5000rpm and having it so smooth, it is becoming a real pleasure.

Cheers, ChrisD (PS: hope my paragraph setting works, thanks to Scaleyback)