Re: Twin 66cc 2 Stroke Build Thread
The easiest way to synch the 2 engines would be to run them both off one way bearings into a common shaft to the wheels, this way the strongest engine will always be providing torque to the jackshaft and the other engine will begin to pull along with the stronger engine during acceleration and when it gets closer to top speed, this will also take the load off one engine if it is slightly stronger than the other so it's only job is to turn the jack shaft instead of helping the other engine and vice versa.
Another trick is to run a synchronizer tube between the 2 intake manifolds so both engines always get the same amount of air regardless of any differences in throttle position, of course, you block off the synch tube while tuning the engines to run as equally as possible, then each output shaft runs off a one way bearing into a common jackshaft, then the manifolds are tied together with the synch tube so both engines can perform as equally as possible at all times.
The one way bearings isolate each engine in case one shuts down or loses power, the other doesn't have to help the weaker engine and by adding a synch tube to connect both intake manifolds, each engine should perform very equally to the other so the same amount of power coming off each engine can feed into the jack shaft which feeds the power from both engines to the rear wheels.
This is the way most multi engine motorcycles are set up so both engines are feeding the same torque into a common shaft, but if one fails for any reason, the other engine only feeds that shaft and don't have to fight against the weaker or failed engine.