The motorcycle is widely used by the community one is the VESPA. On a motorbike vespa many rotating parts, such as the crankshaft is resting on the pads. The bearings have a very important role in maintaining the performance of the machine. Defective bearings will have an impact on his descent engine performance. To reduce impacts more severe bearing defects, then the bearing defect detection becomes important done. Vibration analysis is one way that is often used to detect bearing damage. This analysis is relatively easy to use, more effective and can be done at the time of the machine in case of work without having to stop the machine and unload machine parts. This research aims to apply the envelope analysis to detect disability early bearing on the crankshaft vespa engine. This research method using frequency domain analysis and envelope to detect damage in the path of the ball bearings. Research by way of comparing both methods aim to know which method is superior to detect damage ball bearings. The bearings are single row Danmotor brands with different conditions, namely bearings normal, flawed 0.25 mm, 0.50 mm and disability. the third condition Of the bearing will be tested using different variations of velocity i.e. 1500 RPM and 2000 RPM. Vibration detection using the Sensor will be on the accelerometer connected with Data Acquisition Modules run with Matlab software. The research results show the frequency domain is not able to show the frequency of defective bearings on speed 1500 RPM. The frequency of damage to bearings 0.25 mm and 0.50 mm 1xBPFI appear only on the speed of 2000 RPM. While the envelope method capable of bearing defect frequencies shows followed 3xharmoniknya on both defective bearings and both the speed of the shaft. Envelope method is superior to the frequency domain due to low frequency high amplitude value is eliminated, thus able to detect defective bearings more specifically though still bearing defects early.