Summary

This document describes a gearbox issue I ve been experiencing with my 2024 Honda Monkey in order to help the dealership service department have all the details I can provide.

Since my bike is still under warranty, I am asking that you please investigate and address this issue. I understand that sometimes these mechanical quirks can happen, but this noise and behavior significantly impacts my riding experience and safety.

In this document, I provide links and info for the symptoms I m experiencing with my Monkey, along with the links and info about the symptoms of other owners, since this seems to be a well-known issue that has happened to Monkey and Grom owners around the world.

Please open a case with Honda and repair or replace the faulty parts under warranty. However, please do not undertake any service work that would require a charge without contacting me first.

Thank you for your prompt attention to this concern! Your assistance in resolving this issue is greatly appreciated.

Symptoms

Since about 120 miles on the odometer, I ve noticed an unusual grinding noise emanating from the gearbox once warmed up (typically after 10-20 minutes of riding), specifically when the bike is in 3^rd, 4^th, and 5^th gear.

When this issue occurs, along with the loud noise, there is a noticeable drop of about 5 mph in top speed, making the bike seemingly strain to maintain speed in traffic. This causes me to have to pull over, turn off the engine, restart, and ride until it happens again.

My Video Evidence

The following link is for a videos I made while riding the Monkey on back roads near me, after warmed up (after some 10-15 minutes of riding).

In the video, at 27 seconds, the noise begins in 5^th gear. At about 41 seconds I begin to decelerate and down shift, and you can hear that the noise disappears at 2^nd gear at 57 seconds. At 1:25 I resume riding, going back up through the gears until 1:41 when the noise returns, and I begin to downshift and pull over again. The noise ends again when I arrive to 2^nd gear at about 2:06.

http://hondamonkeywrench.com/IMG_4197.MP4

Other Videos & Information

The following videos are shared by others around the word on YouTube, with the same or similar symptoms. Please also note the comments sections of the videos, as they are rich with information.

In this brief video, you can hear the same noise I have, and note the comments with others telling of their stories:

https://youtu.be/nYHwHwA7nhg?si=aYvWEFY8xusKcsyu

This video is a follow-up to the above, telling the story of his interaction with the dealership. Again, note the comments where details, stories, and part numbers are given. Also, at 9:30 in the video, he shows the layout of the damaged parts:

https://youtu.be/-SetIDr5AS8?si=zHpiyCBflKYagzdJ

In this video, the rider experiences the grinding noise at about 0:20 in the video:

https://youtu.be/cJGifmgfEP0?si=0zAa21JI2pS922nP

This video is on a Grom, but it is the same issue, and people in the comments give more details and stories:

https://youtu.be/Fmiu5IzBFz4?si=SJgOMiifL4puAbt4

(please note the second comment on the video above from @RonMarkarian, as below)

Just adding an update on my 22 monkey. Honda acknowledged this is an issue with a batch of 22 groms/monkeys. Although this occurs after running in 5th gear for 20 minutes or so, the issue was second gear rubbing against the countershaft and heating up to failure. They replaced the following under warranty. 23221K26G00 - Countershaft, 23441K26G00 - Gear (32T), 23415K26G00 - Bush (17MM), 90405KYJ900 - Washer (17x26x1.0), 06111K26G80 - Gasket Kit A, 06112K26G70 - Gasket Kit B, and element/oil filter. They mentioned this would be a $700 fix if not under warranty. I hope this helps..