Yamaha YZF-R125 Service Manual: Poor medium-and-high-speed performance

Incorrect engine idling speed

Engine 1. Cylinder and cylinder head Incorrect valve clearance Damaged valve train components 2. Air filter Clogged air filter element Fuel system 1. Throttle body Damaged or loo ...

Shift pedal does not move

Shift shaft Improperly adjusted shift rod Bent shift shaft Shift drum and shift forks Foreign object in a shift drum groove Seized shift fork Bent shift fork guide bar Transmission ...

Other materials:

Drive chain slack
The drive chain slack should be checked before each ride and adjusted if necessary. To check the drive chain slack Place the motorcycle on the sidestand. TIP When checking and adjusting the drive chain slack, there should be no weight on the motorcycle. Shift the transmission in ...

Protective apparel
The majority of fatalities from motorcycle accidents are the result of head injuries. The use of a safety helmet is the single most critical factor in the prevention or reduction of head injuries. Always wear an approved helmet. Wear a face shield or goggles. Wind in your unprotecte ...

Avoid Carbon Monoxide Poisoning
All engine exhaust contains carbon monoxide, a deadly gas. Breathing carbon monoxide can cause headaches, dizziness, drowsiness, nausea, confusion, and eventually death. Carbon Monoxide is a colorless, odorless, tasteless gas which may be present even if you do not see or smell any en ...