Vibration while idling

11347 Views 20 Replies 15 Participants Last post by badassxr50r, Sep 15, 2014

JimmyD

Discussion Starter · Sep 27, 2013

Hey guys. I took my Grom for its maiden voyage today... feels awesome!

My only complaints were changing the engagement point of the clutch lever (it was almost all the way out and I found I was slipping the clutch at every light) and the vibration at idle!! When we fired it up for the first time, it was shaking like a washing machine and figured... "Well... it's cold, so it will probably even itself out". Nope! It still shakes a lot more than anything else I've owned at idle.

But two things caught my eye... one was the slightest bit of throttle evens it out to a lovely purr... so I'm thinking maybe a slight air screw adjustment.

The other thing that really made me wonder was this: applying the front brake to the point the micro switch "clicks" makes the vibration go away instantly.

I thought... well, maybe the extra load the brake light is putting on the bike makes the RPM go up slightly...? Fuel injection can sense some light engine load like that and act accordingly.

Nope... it can't be that... because the RPMs don't noticibly change, and the same thing happens when I have my foot on the rear brake already (I stop in traffic with my rear... and I was flicking the front on and off... so the rear was already activating the light).

Anyone have any input? This is an odd one for me.

Other than that, I'm SO STOKED! I love my Grom!

Reactions: 1

1 - 20 of 21 Posts

Eurobeaner

· #2 · Sep 27, 2013

Single cyl. They vibrate. It's like hopping on a Harley and expecting a goldwing feeling.

At 900 miles, mine has really smoothed out and doesnt vibrate much at all anymore. (The "Shake your whole vision around" type vibrate)

GromGrom

· #3 · Sep 27, 2013

I noticed the front brake no vibration thing as well I usually hold the rear brake though

laidoutchevy

· #4 · Sep 27, 2013

I have also noticed the bike idles perfectly smooth with the front brake held. I can't figure out why, but oh well.

Eurobeaner

· #5 · Sep 27, 2013

It resonates through the whole bike. I bet if you puts high speed camera pointed at the front wheel while its doing it you would see that the shaking of the engine is moving the front wheel ever so slightly forward and backwards, and since the fork assembly is nice and long, it puts the heavy wheel way out there causing the vibration. Put the brake on, it stops the wheel from moving and the whole assembly becomes more solid.

Along the lines of why you see the stock tail flopping around really bad at idle, but the rest of the bike isn't really moving much. Farther out you get from a solid point, the more movement you get

Like I said, get some miles on it and it really tones down

Reactions: 1

rkwfxd

· #6 · Sep 27, 2013

Mine is smoother when I hold the front brake but it is also getting smoother as it breaks in. I still only have 300+ miles on it though so no where near fully broken in yet.

Ven0m0uS

· #7 · Sep 27, 2013

Look back to see if the rear brake light is on while stopped. My rear brake pedal has to be pressed pretty hard in order to get it to light up (front lever turns it on immediately). Check out the earlier thread on this. Just to check if its related.

Honda_Grom

· #8 · Sep 27, 2013

JimmyD said:
vibration at idle!!

try some different bar ends with slightly more or slightly less weight

JimmyD

Discussion Starter · #9 · Sep 30, 2013

Eurobeaner said:
Single cyl. They vibrate. It's like hopping on a Harley and expecting a goldwing feeling.

At 900 miles, mine has really smoothed out and doesnt vibrate much at all anymore. (The "Shake your whole vision around" type vibrate)

Yeah, I've owned quite a few singles and this is by far the worst... but I've never owned a "flat single" Z50 style bike, so I think you're spot on about the front brake, though. The caliper is holding the wheel still because the piston is literally moving forward and back.

I just hold my front brake in traffic so I look cooler

Capn Kirk

· #10 · Sep 30, 2013

Eurobeaner said:
It resonates through the whole bike. I bet if you puts high speed camera pointed at the front wheel while its doing it you would see that the shaking of the engine is moving the front wheel ever so slightly forward and backwards, and since the fork assembly is nice and long, it puts the heavy wheel way out there causing the vibration. Put the brake on, it stops the wheel from moving and the whole assembly becomes more solid.

Bingo! It is nothing to do with the brake light but as soon as the pressure is applied to the front pads, the wheel becomes solid to the front and the shake goes away. A little annoying but I have learned to just hold the brake.

AJ Nin

· #11 · Oct 1, 2013

It does vibrate quite a bit. My license plate was rattling against the dealers metal license plate bracket till I put some tape between the two. I had a Sportcity 125 scooter that did almost no vibration. Same with the Vino 125 scooter, both with single cylinders. There are other factors apparently than one cylinder. Counterbalancing, rubber mounts, direction of the piston, bore size among other factors.

Ven0m0uS

· #12 · Oct 1, 2013

Capn Kirk said:
Bingo! It is nothing to do with the brake light but as soon as the pressure is applied to the front pads, the wheel becomes solid to the front and the shake goes away. A little annoying but I have learned to just hold the brake.

Grom detectives at work solve another mystery! Scooby snack, anyone?

AJ Nin

· #13 · Oct 1, 2013

That's true. The Grom being so light and easy to roll while in N does seem to be a factor. The little Metropolitan is even lighter at 184 lbs. wet, but scooters really don't have neutral. The Metro is smooth. When I want smooth, I jump on the Zero S where there is no hint of any vibration cause nothing is moving except electrons.

AJ Nin

· #14 · Oct 31, 2013

Speaking of vibration at idle. You might want to use some Locktite on the license plate bracket bolts. I caught mine just before the 2nd bolt vibrated out. Never had that happen before, but you could easily lose your license plate.

JimmyD

Discussion Starter · #15 · Oct 31, 2013

I was just noticing how much the fender moves around at idle last night. Weird that you should post this. It's a sign.

/me checks his bolts ASAP

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banks619

· #16 · Oct 31, 2013

AJ Nin said:
Speaking of vibration at idle. You might want to use some Locktite on the license plate bracket bolts. I caught mine just before the 2nd bolt vibrated out. Never had that happen before, but you could easily lose your license plate.

Lost one of my plate bolts a couple of weeks ago. Definitely check your license plate bolts.

Sent from my iPhone using HondaGrom.net

evo42

· #17 · Sep 15, 2014

Holy Thread re-vive!

Lost my plate yesterday. Thinking loc-tite and zip-ties now. DMV tomorrow...

Jdracer

· #18 · Sep 15, 2014

Lost one nut holding the headers last week. You guys might want to add that to your weekly checklist. It's a m8 1.25 pitch nut if you need a replacment.

Dude6710

· #19 · Sep 15, 2014

evo42 said:
Holy Thread re-vive!

Lost my plate yesterday. Thinking loc-tite and zip-ties now. DMV tomorrow...

Mine vibrated enough that it snapped off of both sides.

CiscoSanJose

· #20 · Sep 15, 2014

mine's vibrate due BrianS 170cc BBK

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