To tighten the chain on a 2007 Yamaha YFZ 450, follow these steps:
- Locate the chain adjuster bolts. These are two bolts located on the rear of the quad, near the wheel.
- Loosen the chain adjuster bolts using a 10mm wrench.
- Turn the chain adjuster bolts clockwise to tighten the chain.
- Tighten the chain adjuster bolts until the chain has about 1/2 inch of slack. It can move up and down 1/2 inch in the center of the swing arm.
- Retighten the chain adjuster bolts securely using a 10mm wrench.
- Test the chain tension by pushing up and down on the chain in the center of the swing arm. The chain should move smoothly up and down with only 1/2 inch of slack.
Note: When adjusting the chain tension, make sure that the quad is in neutral.