This manual first appeared in 1972. Here is the 1973 revised edition. Includes Section 11. XS750(650) Racing Special.

The OW72 motor was developed to take this and the then relevant associated tuning knowledge to another level.

Racing Part numbers referenced in this are found in the Yamaha Racing Parts Book.

 

Yamaha Racing Tips … mostly for the 2 stroke program … includes Section 11 XS750(650) Racing Special

 

YRT contents

 

YRT contents

 

YRT warning

 

Here are the sections. Relevant to XS650s are Sections 1 and 11 …

• Racing Tips. Section 1. Introduction …

1. Using a degree wheel,
2. Tips for cutting parts,
3. Cylinder Head mods,
4. Porting mods,
5. Piston mods,
6. Rotary Valve mods,
7. Con Rod mods,
8. Expansion Chambers,
9. Spark Plug selection,
10. Carb Adjustments

• Racing Tips. Section   2. JT1 and 2    Enduro, Motocross, Motocross Special
• Racing Tips. Section   3. LT2     Enduro, Motocross, Motocross Special
• Racing Tips. Section   4. AT2     Enduro, Motocross, Motocross Special
• Racing Tips. Section   5. CT2    Enduro, Motocross, Motocross Special
• Racing Tips. Section   6. DT2    Enduro, Motocross, Motocross Special
• Racing Tips. Section   7. RT2    Enduro, Motocross, Motocross Special
• Racing Tips. Section   8. LS2    Street, Special, TA125 Road Racer
• Racing Tips. Section   9. DS7   Street, TD3 Special
• Racing Tips. Section 10. R5     Street, TR3 Road Racer, TR3 Special
• Racing Tips. Section 11. XS650-750

If you have ended here and not where you want to go – VOU HAVE A VIRUS ON YOUR COMPUTER … do us both a favour and scroll back to my blog post Virus. Please read this then do a search as suggested.

Yamaha Troubleshooting Manual

In 3 languages. English. French. German

 

Troubleshooting Manual

 

Yamaha Troubleshooting Manual

 

Trouble Shooting

– hopefully this can prove organic … comments and suggestions – correcting, extending
– an engine is basically an air pump – 4 stroke …  suck, squeeze, bang, blow
– add fuel, timing and spark = internal combustion engine
– break this system anywhere and you wont get much action

– so your engine turns over ? wont start
– what have you done ? what have you changed, altered, played with, unfixed ?
– air ? fuel ? spark ? …all in the correct ammount and moment ?
– don’t panic…turn the key and petcock/s off, step back …take a breath-deep, go do something you really enjoy for a couple of minutes…

•  fuses ? kill switch ?
•  battery ? 12.6 V ? put it on charge, brushes ? check charging system
• power to coil/s ? points spark ? plugs ?
• filters ?
• fuel to carbs ? bowls ? cylinders ? floods ?
• compression ? leak-down test ?

·

•    adjust your cam chain … can readjust warm once you get her running
•       set your tappets
•       set your points if you have them .. plugs

 

– once you get this far she should be at least spitting and farting enough to attempt setting your carbs …

• if she wont idle, look for air leaks ? atu ? massage her pilot jet circuits
• once you can get idle, do the idle speed screw/pilot air screw dance
• smooth transition through to full throttle ?
• synchronise

Electric Troubleshooting

Carburetor Troubleshooting

Starting System Troubleshooting

Engine Troubleshooting

Oil Troubleshooting

Clutch and Gearbox Troubleshooting

Frame Troubleshooting