1. Measure the bearing to crankshaft main journal clearance using Plastigage (Triumph part number 3880150-T0301). Use the same method as described in connecting rod clearance measurement.
Checking crankshaft clearance using Plastigage
| Crankshaft main bearing/journal clearance | |
| Standard | 0.018-0.041 mm |
| Service limit | 0.100 mm |
2. If the clearance exceeds the service limit, measure the diameter of the crankshaft main bearing journal.
| Crankshaft main bearing journal diameter | |
| Standard | 43.092-43.108 mm |
| Service limit | 43.068 mm |
Note: If any journal has worn beyond the service limit, the crankshaft must be replaced. Due to the techniques used during manufacture, the crankshaft cannot be reground and oversize bearings are not available.
Select bearings as follows:
1. Measure and record the diameter of each crankshaft main bearing journal.
2. Measure and record each main bearing bore diameter in the crankcase (bearings removed but all crankcase bolts fully torqued (see page 5.8).
Note: The original crankcase bolts may be reused for bearing selection. Do not use new bolts as they may only be used once, even if the single use is related to bearing selection.
Compare the data found with the chart above to select bearings individually by journal
| Shell Colour | White | Red | Red | Blue | Blue | Green |
| Crankcase bore diameter | 46.105 to 46.097 | 46.105 to 46.097 | 46.114 to 46.106 | 46.114 to 46.106 | 46.123 to 46.115 | 46.123 to 46.115 |
| Crankshaft journal diameter | 43.108 to 43.100 | 43.099 to 43.092 | 43.108 to 43.100 | 43.099 to 43.092 | 43.108 to 43.100 | 43.099 to 43.092 |
For example:
- Crankcase Bore — 46.099 mm
- Crankshaft Journal diameter — 43.095 mm
- Bearing Required — BLUE
Note: It is normal for the bearings selected to differ from one journal to another.
It is also normal for there to be two options of bearing shell colour. In such cases, pick the shell size that gives the greater running clearance.
Warning! Always confirm, using the Plastigage method, that the running clearance is correct before final assembly. Severe engine damage could result from incorrect clearance resulting in loss of motorcycle control and an accident.
Crankshaft end float
| Crankshaft end float | |
| Standard | 0.05-0.20 mm |
| Service limit | 0.40 mm |
Note: Crankshaft end float is controlled by the tolerances in crankshaft and crankcase machining. Thrust washers are not used. If crankshaft end float is outside the specified limit, the crankshaft and/or the crankcases must be replaced.