Transmission Scream/Screech/Howl at speed?

[zigzagjoe]

Unfortunately, I'm having a bit of an issue with my Trail. After the bike is fully warm and cruising ~50MPH for an extended time, I'm getting a fairly awful screech noise out of the transmission. Like a slipping belt, almost, except there's no belt to slip. Slowing down significantly usually resolves it temporarily. Issue won't occur if it's not warm and in all other regards the bike runs completely fine.

It seems like some Groms and Monkey riders may be having a similar issue, though I haven't 100% confirmed this yet. Unfortunately the consensus from Grom owners seems to be "run it til it catastrophically fails, then the dealer HAS to fix it" which very much rubs me the wrong way. I'm going to try to capture the sound and post it somewhere, then maybe try working on a dealer. Considering Grom owners run very similar engines and transmissions harder than this, I can't help but think I've got a defect here. Oil temperature I measured last night was somewhat concerning also, though it's the first measurement I've taken so far.

Follows is my big long set of notes that I intend to furnish to them when I get to that point.

Anybody encountered this before?

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Symptom

Howling noise from drivetrain at sustained high speed. Sounds like a screeching, shrieking mechanical howl. Similar to a slipping belt.

Issue first observed around 250 miles, after break-in period elapsed and higher speeds were allowed. Issue has persisted since.

Replication

• Ambient temperature does not seem to matter.
• Bike must be fully warmed up (~ 25 minutes of riding)
• Maintain 45+MPH with heavy throttle in 4th gear. Should always occur around 50MPH.
• A shrieking noise should be observed after a period of time (3-5 minutes?) at speed. If the clutch is disengaged, it becomes much louder. The sound may go away after re-engaging clutch rapidly, but only significant deceleration and rolling off throttle has been found to always resolve. Sound will re-occur after another short period of time.

Notes

• Disengaging clutch is accomplished by attempting to shift into a 5th gear (does not exist) and holding.
• Noise becomes notably louder if clutch is disengaged.
• Noise follows drivetrain speed, not engine RPM. Applying front or rear brake does not make any change in sound.
• Noise has been observed to become extremely (concerningly) loud if fully roll off throttle and let the bike engine brake. This seems to also occur if putting in clutch after noise starts and allowing engine to idle while bike coasts.
• Noise typically goes away as speed of bike drops, but it has been observed coming and going while maintaining fixed speed and throttle.
• If noise is ignored, drivetrain noise will take longer to return to normal after reducing speed.
• During recent replication, oil temperature of 240 degrees F observed with a temperature probe through dipstick hole. This is after cruising at 30 mph for a while after the period of high speed (50mph) riding.

Maintenance

Oil changed with Honda GN4 10-30 at 580.5 miles. Chain tension has been monitored but not found to be out of acceptable range at any time. Tires appropriately aired. No modifications to bike performed.

 

[dmonkey]

Sounds like the same issue mentioned here: https://www.hondagrom.net/threads/a...ing-this-noise-issue.47973/page-2#post-496340

Talk to your dealer about it, ask if they're familiar with the issue. If you have a GoPro or phone mount, try to document it on video. For a different bike with an intermittent issue that happened when the bike was up to temp (bad cam belt roller bearings) I scheduled a time to drop it off, rode the bike for 45 minutes then handed it off to the mechanic at the scheduled time for them to reproduce the issue and they were able to. The hard part is documenting the issue, once you have it documented the shop will have something to work off of to get it fixed or replaced under warranty.

 

[zigzagjoe]

Yeah, that's one of a few related threads I saw that seems to reflect a similar issue. I tried to grab it last night, but phone mics didn't stand a chance against 50MPH wind. I have an action camera but the audio is pretty awful. I'm going to try to get it with an audio recorder.

Getting the bike good and warm first is a good idea. I'll have to try that. I purchased my bike 5 hours away, hoping the local dealers don't give me too much trouble trying to get warranty work done.

 

[zigzagjoe]

I captured the sound a few times and uploaded it to soundcloud. Any thoughts appreciated... I don't see any way this doesn't involve getting the dealer involves as it sounds like a bearing to me.

https://soundcloud.com/zigzagjoe%2Fsets%2Fhonda-trail-125-transmission-issue
Clutch in, clutch out: (appx 20 minutes into the ride)
45 mph - full throttle
noise occurs
Clutch in (gets noisier) and back out quickly (goes away).

Brake test: (about a minute later)
Steady at 50mph
noise occurs
clutch in (gets louder)
front brake (no change)
rear brake (no change)
clutch out (goes away)
40mph

Engine braking: (about 3 minutes later - stopped for a sec)
steady at 50mph
noise occurs
Noise gets truly awful sounding
engine braking to 35mph

 

[dmonkey]

That doesn't sound good. Have you talked to the dealer about it yet? To be clear it doesn't have to be the one you purchased it from, you can bring it to any Honda Powersports dealer to have it looked at for a warranty issue.

 

[MisterB]

That's harsh. Fingers crossed that your future posts will be praise of Honda for making this right.

 

[zigzagjoe]

Now that I have the sound recorded I've put in for an appointment with the nearest honda dealer to get it looked at. I'll update with the outcome from that....

 

[rightspy]

Wow, sounds like metal on metal. Good luck.

 

[SneakyDingo]

That is definitely not a sound my bike makes

 

[zigzagjoe]

Sigh. I dropped the bike off this Tuesday after a 3 week wait. Today, I get the call - we weren't able to replicate the issue. Maybe its normal, or it's the weird auto clutch. Or you're in too high a gear. When asked, they did not follow instructions and had been testing it cold or at low speed stop and go through neighborhoods.

I was really trying to not be pessimistic about my expectations for this experience but, man, does it suck to be proven right. I'm really hoping I don't have to be difficult but if that's what has to happen, so be it. Driving 40 year old cars and motorcycles you get a sense of what is a Noise and what is a Problem Noise; this is very much the latter. It's not like I'm abusing it, either - this engine comes from the Grom, and Grom riders run them harder than I do.

Saturday I go in to do what I originally suggested: I get the bike good and warm so they can hop on and hopefully replicate it fairly quickly. Going to bring audio recorder and get a fresh recording also.

Incidentally, on the way there it started making the wretched noise that occurs in the engine breaking recording while throttled up (not braking). So it's getting worse.

 

[m in sc]

got a go pro? film it.

 

[zigzagjoe]

I have an action camera but the audio is unusable. Ditto for phone. So far the audio recorder to has been the only thing with usable audio quality.

 

[m in sc]

hence why i said go pro. see if you have a friend that has one, film it, take it w you. if they wont budge, send it to honda .02

 

[ShieldArc]

I guess you will have to blow it up and take it back and say I told you so....

 

[DJ427]

You might try one of those shift shaft support things, it makes sure everything is in perfect alignment in the clutch and gearbox

 

[m in sc]

pretty sure a support will have zero effect, thats a bearing or side clearance issue rearing its head or similar when the motor gets warmed up.

want them to look at it under warranty? drain the oil out, save it, run the motor around for like 20 minutes or until it fails, put the oil back in and go in like ' i dunno what happened?'

new motor.

 

[DJ427]

pretty sure a support will have zero effect, thats a bearing or side clearance issue rearing its head or similar when the motor gets warmed up.

You don't know what the fuck you're talking about.

 

[m in sc]

I'm the one who 1st suggested it on this site for reducing the flex in the shaft, which has -zero- to do with what's going on here. did you actually listen to the sounds? that's a bearing. but wtf do i know.... right? How many motorcycle transmissions have YOU rebuilt?

 

[eastema]

I had an old h2 750 2 stroke, rode it with no oil in the transmission. 20 miles into the ride, I had that noise. It was from one of the transmission gears had galled on a shaft and spun some metal loose. But it doesn't sound like you have a no oil prob.

 

[m in sc]

yup. wiped a bearing on a 73 H1 clutch (input shaft) & one of my rds 4th gear just went tits up made similar noises both. Once you hear it, you never forget it.