This bearing is important as it was fitted to the timing-side crankshaft journal on the Triumph 650 engines from engine number GE27210, and 750 models through 1980. It is not compatible with earlier 650 crankshafts and crankcases, including the earlier production 1971 models prior to June 1971.
This quality NSK bearing is the 6306 metric bearing that was fitted to Triumph 650 and 750 twin-cylinder engines after engine number GE27209. The deep groove radial ball bearing is an open-type specified in C3 clearance. Measuring 72mm OD, 30mm ID, and 19mm wide, this is the bearing that Triumph used in the timing-side crankcase half after a world-wide shortage of the original 70-1591 bearing occurred. The crankcase and crankshaft were machined to fit this bearing specifically on engines through the 1980 model year.
The ball bearing supports the right side of the crankshaft and must be in good condition to produce a quiet running and smooth engine. C3 radial internal clearance is specified for this application.
Generally, the empty timing-side crankcase is heated to allow for slight expansion of the bore. It is recommended to freeze the bearing for several hours to slightly contract the outer race enough to simply drop it into the hot crankcase bore without the need for drifting the bearing into place. The factory workshop manual procedures should be reviewed and followed prior to fitting the bearing.
Please note: Due the nature of the product, we unfortunately do not accept returns on bearings, service tools or electrical components. Please be confident about your purchase before ordering. If you have questions, please contact us.