- Crankshaft runout
Out of specification → Replace the crankshaft.
Crankshaft runout limit 0.030 mm (0.0012 in).
![](https://motoinstruction.ru/img/yamaha/20/126774.jpg)
2. Check:
- Crankshaft journal surfaces
- Crankshaft pin surfaces
- Bearing surfaces
Scratches/wear → Replace the crankshaft.
3. Measure:
- Crankshaft-journal-to-crankshaft-journal bearing clearance
Out of specification → Replace the crankshaft journal bearings.
Journal oil clearance 0.004-0.039 mm (0.0002-0.0015 in).
Notice: Do not interchange the crankshaft journal bearings. To obtain the correct crankshaft journal-to-crankshaft-journal-bearing clearance and prevent engine damage, the crankshaft journal bearings must be installed in their original positions.
a. Clean the crankshaft journal bearings, crankshaft journals, and bearing portions of the crankcase.
b. Place the upper crankcase upside down on a bench.
c. Install the crankshaft journal upper bearings "1" and the crankshaft into the upper crankcase.
Align the projections "a" on the crankshaft journal upper bearings with the notches "b" in the upper crankcase.
![](https://motoinstruction.ru/img/yamaha/20/126775.jpg)
d. Put a piece of Plastigauge® "1" on each crankshaft journal.
Do not put the Plastigauge® over the oil hole in the crankshaft journal.
![](https://motoinstruction.ru/img/yamaha/20/126776.jpg)
e. Install the crankshaft journal lower bearings "1" into the lower crankcase and assemble the crankcase halves.
- Align the projections "a" of the crankshaft journal lower bearings with the notches "b" in the lower crankcase.
- Do not move the crankshaft until the clearance measurement has been completed.
![](https://motoinstruction.ru/img/yamaha/20/126777.jpg)
f. Tighten the bolts to specification in the tightening sequence cast on the crankcase. Refer to "Crankcase".
g. Remove the lower crankcase and the crankshaft journal lower bearings.
h. Measure the compressed Plastigauge® width "a" on each crankshaft journal.
If the crankshaft-journal-to-crankshaft-journal-bearing clearance is out of specification, select replacement crankshaft journal bearings.
![](https://motoinstruction.ru/img/yamaha/20/126778.jpg)
4. Select:
- Crankshaft journal bearings (J1-J5)
- The numbers "A" stamped into the crankshaft web and the numbers "B" stamped into the lower crankcase are used to determine the replacement crankshaft journal bearing sizes.
- J1-J5 refer to the bearings shown in the crankshaft illustration.
- If J1-J5 are the same, use the same size for all of the bearings.
For example, if the crankcase J1 and crankshaft web J1 numbers are 5 and 2 respectively, then the bearing size for J1 is:
J1 (crankcase) - J1 (crankshaft web) = 5 - 2 = 3 (brown).
Bearing color code:
- 1.Blue
- 2.Black
- 3.Brown
- 4.Green
- 5.Yellow
![](https://motoinstruction.ru/img/yamaha/20/126779.jpg)
![](https://motoinstruction.ru/img/yamaha/20/126780.jpg)