2024 Honda Monkey Gearbox Issue

Jeremy@HondaMonkeyWrench.com

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 3rd, 4th, and 5th 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 5th gear. At about 41 seconds I begin to decelerate and down shift, and you can hear that the noise disappears at 2nd 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 2nd 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..

The Diary of Events

  • 20231209 - Out for a ride on a nearly 60-degree December day, at roughly 110-115 miles, a noise starts coming from the transmission.It seemed to only be noisy in 4 & 5th gear, and it was only present while in motion, and only after ~20-30 minutes of riding. Not far from home, I returned, and researched, and found other Monkey and grom owners with similar symptoms, mostly related to oil starvation. I checked and found the oil to be at the bottom of the safe range, so I added oil to the top of the safe range and no more noise. 20231215 - Out for a ride on a 55-degree day. About 20 minutes into the ride, the noise begins again in 4th/5th gear. I immediately pull into a subdivision to check the oil, and turn off the power. The oil level is good, but it appears that the oil had a bit of a foamy layer at the top. Started back up after that probably 30-60 seconds, and thinking I'd take side roads home, but the noise did not re-appear for the 4+ miles home.
  • 20240312 - I have contacted C & C Sports in Brighton regarding the issue, spoke to Ryan, who asked for a video of the symptom, and a pic of the VIN and the ODO. Today I provided these things to Ryan and he says he will open a warranty case with Honda for me.
  • 20240401 - After not hearing anything for a couple weeks, I re-contacted C & C Sports, who told me that they won't open a case in advance after all, and I should really go back to the dealership I bought it from to have it looked into. So that's what I'll do...
  • 20240401 - Called Savannah @ MotorCity - She said I have a 1-yr warranty, and I should write it up, bring it in, have them open the case BEFORE working on it. If Honda won't cover it, then we plan from there.
  • 20240410 - Took a ride around town to capture the transmission failure on phone camera video.
  • 20240421 - Built a simple website to document the issues: http://hondamonkeywrench.com/
  • 20240510 - After gathering all my notes, videos, evidence, and multiple calls to MotorCity, I rented a U-Haul trailer and towed the Monkey to MotorCity Powersports. I brought it in with the agreement that MotorCity would immediately open a warranty case with Honda, and the hope that would be enough to get the work done immediately.
  • 20240521 - MotorCity Powersports Mechanic's notes from work order: "the noise the customer is hearing is an internal transmission issue. will need to start a case with honda to see how they want us to handle this issue MG 5/21/24"
  • 20240603 - Got a call from Motor City Powersports. Honda will not approve repair without teardown. Initial estimate for complete teardown and rebuild would be somewhere around $900 (6h @ $149), and I have to cover it. I about lost my mind and asked if I could call Honda myself and ask why I have to pay for a diagnosis of an obvious warranty repair for a VERY common issue (for which I provided evidence).. I was given the Honda warranty support phone number and my case number and info.
  • 20240603 - Called Honda warranty support, spoke to Tim. I asked why I had to pay over 25% of the bike's cost to diagnose what is clearly a known issue, and should be a recall. Tim told me that Honda didn't know what the issue was and it could be my fault. Once Tim basically accused me of damaging the bike though my misuse, I lost my temper a bit and he suggested I speak to Customer Relations, because he wasn't going to do anything about it. I relented, because I thought speaking with Customer Relations might bring some sanity because Tim was not kind nor helpful, and since clearly Customer Relations would have heard of this known issue... right...? So Tim forwarded my call, and I spoke to Gina in Customer Relations, who told me a reviewer would review the case and see if I can be helped.
  • 20240604 - Got a call from Jasmine, who asserted that Honda will not approve without inspection by certified mechanic. This was actually the first of a handful of calls with Jasmine, each time elevating the temperature a bit. I asked for just about every alternative approach (like, can I provide more information or corroboration, perhaps reaching out to the others who have had this issue? can I disasemble it to prove the damaged parts? Can you just send me the parts and I'll fix it myself? ). She kept insinuating that it was my fault, and she would not admit to Honda having previous knowledge of the issue. Also, she kept using a tactic to suggest that all the YouTube videos and my documentation of the same issue are not trustworthy and don't mean anything. Unfortunately, I eventually lost my temper at her becuase I just couldn't stand being acused of damaging the bike myself. It was becoming clear to me that Honda was not going to cover the issue, and I was going to have to find a lawyer to pursue them. But, the only way to take the next step toward gathering evidence for a legal case is also to proceed with the COSTLY teardown out of my own pocket, so I'd have something to sue them for... I was cornered, and it's one of the worst feelings. Honda is clearly a terrible company to do this to someone over such a well-known/common issue. I realize now that buying a Honda is a mistake that I will never make again, but I have to get through this money pit.
  • 20240606 or 07 - I forget the date, but I eventually surrendered and called MotorCity to explain my failure to get Honda to cover the warranty issue. I told them it was becaoming clear that Honda was accusing me of the damage and that I may not be able to afford the repair on top of the teardown. I wanted to know what my different costs would be with different approaches, such as if we do the teardown and Honda refuses, what it would cost to just put it back together as-is and pursue Honda legally, or for me to cover the cost myself and try to sell the bike, etc. I asked what each part in my parts list would cost, along with all the labor to install them. MotorCity gave me what I consider a very kind/fair price to proceed, and I approved the teardown. I asked MotorCity Powersports please give me copies of everything they provide to Honda (photos, write-ups, etc.), since I woild clearly need them for a lawsuit. I took the plunge, but assumed that in the end I'd be trying to sell the a broken bike for parts and take a big financial loss. Ugh. Biggest mistake ever.
  • 20240611 - MotorCity PowerSports mechanic's notes from work order history: "found second gear, second gear bushing and countershaft to have heat damage. this will be the causing of the customers transmission issue MG 6/11/24"
  • 202406?? - Somewhere in late June, I forget when, I got a call from MotorCity Powersports explaining that they had a very simple call with Honda, who said something to the affect of, "...yep, we've seen that, we'll cover it". While I was happy that it was going to be covered, I was flabbergasted that Honda had to put me through all of the accusations and obfuscations just to cover it anyway. What a horrible company. Selling defective items happens, but I don't understand why they had to put me through all that for a known issue that should have been a recall. Ugh.
  • 20240720 - From MotorCity Powersports mechanic's notes: "during reassembly it clutch pressure plate broke. will need to order new part MG 7/20/24"
  • 20240730 - From MotorCity Powersports mechanic's notes: "engine assembly complete. took machine for 4 mile test ride to verify everything is working properly and there is no oil leaks. machine is ready to go MG 7/30/24"
  • 20240731 - Picked up the Monkey from Motorcity Powersports and rode home with no issues. Wow.

    Parts list for warranty repair

  • 23221-K26-G00 - Countershaft
  • 23441-K26-G00 - Gear (32T)
  • 23415-K26-G00 - Bush (17MM)
  • 90405-KYJ-900 - Washer (17x26x1.0)
  • 06111-K26-G80 - Gasket Kit A
  • 06112-K26-G70 - Gasket Kit B
  • 10/40 Oil