Chapter 1. General Information


Frame Serial Number

The frame serial number is stamped into the rightside of the steering head pipe.

Starting Serial Number:


Engine Serial Number

The engine serial number is stamped into the elevated part of the right rear section of the engine.

NOTE: The first three digits of these numbers are for model identification; the remaining digits are the unit production number.

NOTE: Designs and specifications are subject to change without notice.



The proper special tools are necessary for complete and accurate tune-up and assembly. Using the correct special tool will help to prevent damage from improper tools or improvised techniques.

For tune-up

1.      Compression gauge P/N. 90890-03081

2.      Inductive timing light P/N. 90890-03109

3.      Inducive tachometer P/N. 90890-03113

4.      Fuel level gauge P/N. 90890-01312

5.      Vacuum gauge P/N. 90890-03094

This gauge is needed for carburetor synchronization.

For engine service

1. Clutch holding tool P/N. 90890-04086

This tool is used to hold the clutch when removing or installing the clutch boss lock nut

2. Tappet adjusting tool P/N. 90890-01245

This tool is necessary to replace valve adjusting pads.

3. Valve guide reamer P/N. 90890-01227

This must be used when replacing the valve guide.

4. Valve seat cutter set P/N. YM-91043

This tool is needed to re-surface the valve seat.

5. Valve guide remover P/N. 90890-01225

This must be used to remove the valve guides.

6. Valve guide installer P/N. 90890-04017

This tool is needed for proper installation of the valve guides.

7. Valve spring compressor P/N. 90890-04019

This tool must be used for removing and installing the valve assemblies.

8. Piston ring compressor P/N. 90890-04044

This is used to compress piston rings when installing the cylinder.

9. Piston base

P/N. 90890-01067

Use 4 of these to hold the piston during cylinder installation.

10. Rotor puller

P/N. 90890-01080

This tool is needed to remove the A. C. generator

11. Rotor puller attachment P/N. 90890-04052

This tool is needed when removing the A. C. generator rotor together with the rotor puller.

12. Rotor holding tool P/N. 90890-04043

This tool is used to hold the A. C. generator rotor during removal and installation.

13. Piston pin puller P/N. 90890-01304

This tool is used to remove the piston pin.

14. Y. I. C. S. (Yamaha Induction control system) shut off tool P/N. 90890-04068

This tool is used to carburetor synchronization.

15. Plastigauge set "Green" P/N. YU-33210

This gauge is needed when measuring clearance for connecting rod bearing.

For chassis service

1. T-handle

P/N. 90890-01326 Damper rod holder P/N. 90890-01365

This tool is used to loosen and tighten the front fork cylinder holding bolt

2. Fork seal driver

P/N. 90890-01367

Fork seal driver attachment

P/N. 90890-01371

This tool used to reassemble the front fork.

For shaft drive service

1. Middle drive pinion holder P/N. 90890-04080

This tool is needed when measuring gear lash.

2. Middle and final gear holding tool P/N. 90890-01229

This tool is needed when measuring gear lasn.

3. Torx driver (# 40) P/N. 90890-04049

This tool is used to loosen or tighten the drive axle bearing stopper bolt

4. Dial gauge

P/N. 90890-03097

This too is used when measuring gear lash for middle and final gear.

5. Gear lash measurement tool (Final gear) P/N. 90890-01230

This tool is needed when measuring gear lash for final gear.