Honda Monkey 125 Chain Adjusting Bolt (2019+) #4

Small part, big job. The chain adjusting bolt (40542-K0F-T00) is the threaded adjuster in your Monkey 125's swingarm that sets rear chain tension and keeps your axle aligned. This is the genuine Honda OEM replacement for 2019+ Monkey 125 models.

These bolts take abuse — road grime, chain lube, and constant thread engagement mean the threads can gall, seize, or round off over time, especially if the chain's been adjusted a lot or the bike's seen weather. A stripped or frozen adjuster turns a five-minute chain adjustment into a knuckle-busting fight. Swapping in a fresh OEM bolt keeps your adjustments smooth and your axle where it belongs.

Genuine Honda means correct thread pitch, correct length, and a guaranteed fit — no cross-threading, no aftermarket tolerance issues.

• Fits: Honda Monkey 125 (2019+) 
• Part #: 40542-K0F-T00
• Function: Rear chain tension adjustment / axle alignment
• Type: Genuine Honda OEM
• Sold as: Single bolt