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Discussion Starter #1
I picked up my Monkey just over a month ago. I now have just over 600 miles on it, but since new, I've had an issue with 3rd gear. Maybe 15% of the time, I shift into 3rd around 29 or 30 mph and things seem okay, but a second or two later as the revs climb in 3rd, I will feel the transmission slip for a split second. The revs jump slightly and then go back to where they were, continuing to climb as normal. Occasionally this "slip" will happen again before I shift to 4th. When I then clutch in and shift into 4th, I find that I cannot. The lever does not move. I then clutch out and try again. This time I can shift into 4th no problem. The problem going into 4th only happens if I get the slip in 3rd. Otherwise it shifts as a normal bike.

When I got to 600 miles, I changed the oil and cleaned the screen and spinner to see if it would make a difference. I expected to see some kind of large chunk, but it looked normal, at least going on what I've seen online from Groms. Since I continued to have the problem, I took it to the dealer and had them perform the first service and test ride it. They performed the service and told me to pick it up. No problem. I took it out for a ride from the dealership and the first time I shifted into 3rd, it slipped as it had done for me before. I continued to ride around for another 10 minutes or so and got it to slip again. Back to the dealer, and back out the tech went on my bike to reproduce it. Again he said he did not find a problem. I hemmed and hawed back and forth with him about the issue. I'm fairly annoyed at this point, and not being able to ride 2 up makes this more difficult to prove. I left the bike with the dealership. I'm planning to strap on a go pro or something to show my experience with the slipping transmission, but right now I'm just doing research to see if this is something anyone has seen before.

Notes:
1. The clutch itself has never slipped. I adjusted it to be in the middle of the pull. Both the factory and the dealer think it should be further out, but I don't believe this to be a clutch issue anyway.
2. The slip has only ever happened in 3rd gear, never any other gear.
3. The failure to shift into a higher gear only happens when going into 4th, and only after the slip in 3rd.
4. Neutral is a pain to find. Not impossible, but it is the most difficult of any bike I've ridden.
5. Below 1st and above 4th are both springy and vague. This may be true of all Monkeys, but it is a new experience for me.

Any ideas? This really seems like a transmission problem, but I am really outside my depth in troubleshooting this issue.
 

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The slip is you not fully engaging the gear. With a motorcycle you really don't need to use the clutch to shift. Put pressure on the lever chop the throttle and it will click up. Some also refer to this as a false neutral.

Riding time on the bike will likely fix it. Also it can definitely get stuck where it won't go up my old Grom and monkey have done it.
 

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how the shift mechanism works is by a ratcheting action. in other worse the shift lever MUST return to the neutral position before the next gear can be selected.


if there is any binding or excessive friction in the shift lever, it may not return the ratcheting mechanism to neutral where it can select the next gear.


check your shift linkage and lever for any binding. chances are that sometimes when you select third, you don't get the ratcheting mechanism to fall into place, so the gear is only partially engaged, it may fall out under load, then back in when unloaded (basically the shift detent is not resting in one of its fixed positions)


the reason you can't select 4th is because the ratcheting mechanism is not reset.




so basically just check that all linkages and levers operate smoothly and the shift arm returns to its normal position after each travel of the lever.
 

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Discussion Starter #4
That's basically my hypothesis: there is something in the gearbox preventing 3rd from being fully selected at times, or as you mention, . I've heard of hitting neutral when attempting a 1st to 2nd shift, but not failing to select another gear. When hitting neutral, it had generally happened to me when I'm especially lazy. The fact that this ONLY happens when shifting to 3rd makes me think this problem exists inside the gearbox. A forceful shift from 2nd to 3rd still shows this problem.

I also tried the MNNTHBX shift lever for a bit and the issue persisted. That lever does away with the linkage altogether.
 

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If a transmission is new it will typically be roughest at that time. As the engine breaks in so does the transmission. But sloppy, lazy shifting is bad for a transmission. Enough of it and you'll slowly ruin the transmission.

Talk to the service manager and request a better mechanic. If not contact Honda and tell them the dealership sucks. The threat of calling the OEM, alone, will sometimes get action from a dealer. You can also try a different Honda dealer.
 

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Discussion Starter #8
Dealership called. Still hasn't replicated the problem. I'm planning to take my gopro there and record a short test ride.
 

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I still think it's the monkey. The one riding it. ? But seriously my Grom and monkey have done what you described but only when I didn't properly fully engaged top gear. Usually lazy shifting.
 

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Discussion Starter #10
Well, after riding fellow forum member, Swampass's, Monkey, I think I'm the problem. Though his transmission is a bit smoother with neutral not being a bear to find, I was still able to get 3rd to slip. I did not have the issue getting into 4th afterwards, however. At this rate I may just ride the bike as is in the hopes that it gets better. It's not really a deal-breaker right now if all of these bikes are the same as it's more of an annoyance and not a safety or reliability issue.
 

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this is a new bike, ride it like you stole it, really, those parts internal to the crank case needs to be worn, make sure you shift it into gear. I like to bang my gears in and sometimes I power shift my gears meaning no clutch "old school let off on the gas and kick it into the next gear with no clutch", yes it's wrong and dangerous but it's my grom and if I break it I fix it. I have over 11K miles on both of my groms and they are now 5 sp transmission units and like you when these 5 sp was new it had a hard time shifting into gears until I had some break in miles on those gears.

Good luck
 

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OP, I have the same issue and cant work out if it really is to do with missing 4th from 3rd. The reason being is that the bike seems to change up, looses power momentarily and pulls again. I'm thinking its ECU related. It is very difficult to reproduce the fault which is why I haven't taken it back to me dealer but I did mention it when going in for first service. They performed an ECU reset but the fault is still there.....although only very occasionally now.

I also had a strange thing the other day. I was going downhill and approaching 67mph on the clock and the resonance of the engine changed to more of a shudder and missfire. I can only assume it is a rev limiter kicking in but again, I have not managed to reproduce this behavior since. It has made me feel like I may have an ECU issue or other sensor / electrical fault or something. There must be more than just the two of us that have experienced this surely?
 

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Discussion Starter #15 (Edited)
I don't think it's ECU related. I think it is more mechanical in nature, at least in my case.

I ordered a shift support bracket from Hard Racing, but I haven't installed it yet or really ridden the bike much since getting it back from the dealer. I'm planning another day trip this Friday and should put close to 200 miles on the bike with the bracket and a new 14t sprocket. We'll see if the problem persists.

As for the rev limiter, I have never hit it in 4th gear. I've seen as high as 69 on the speedo (stock gearing) going down a hill while tucked in as close as I can. The bike's stock gearing is pretty tall for the amount of power it makes.
 

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I also had a strange thing the other day. I was going downhill and approaching 67mph on the clock and the resonance of the engine changed to more of a shudder and missfire. I can only assume it is a rev limiter kicking in but again, I have not managed to reproduce this behavior since. It has made me feel like I may have an ECU issue or other sensor / electrical fault or something. There must be more than just the two of us that have experienced this surely?
Definitely the rev limiter. With the 14T sprocket on the front of mine I can hit the limiter in every gear and it vibrates/shudders the bike like a wild beast.
 
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