[Dregali91]

Bought the Grom used with 750 miles on it... seller said bike has sat for 2 months

It has a 13t sprocket on it which I love btw, but when I'm at speeds above 45 it seems like the bike shakes and is a very rough ride. I feel like it should be butter smooth unless the roads are obviously bumpy, which they are not.
After I noticed it I filled the tires to the recommended 29psi, tightened the chain, but nothing improved. It almost feels like a wheel is unbalanced or a rim is bent. The bike is still under Honda warranty so if its a problem like that I'll take it there to get fixed.

Possible problems?
Rim bent
unbalanced wheel
13t sprocket causing this?
I have no clue

Anyone have an opinions on what I should fix or anything?

For reference- 6'3" 210lbs. Weather is in the 30s

 

[CiscoSanJose]

Check tire for proper install and rotation, All/most motorcycle tires have a arrow embedded on the tire showing the proper rotation.

lift the Grom off the ground and check front and rear tire rotation and see if there is any wobble which would indicate bent rim, bad wheel bearings, out of spec front or rear axle torque nut.

You mention 13T engine/counter gear change, check the alignment of the chain to make sure the rear sprocket and chain are lined up correctly and the tooth of the rear sprocket is close to the center of the chain when you are rotating the rear tire forward or back wards when the tire is up on a stand at the same time you can check for chain adjustment to make sure you have the proper tension on the chain. Use your Grom service manual to find out the proper adjustment.

Good Luck

 

[StrayDog]

The fact you bought it second hand the first thing I would check is the rim is true
It won't be the 13t sprocket that's for sure.
Sitting a couple of months wont do it any harm.

Dog

 

[Dregali91]

I put the bike on a stand and put it in first, I noticed the back wheel wobbling slightly. wheel not true?

 

[MotardCrazy]

More likely not aligned. Check the axle blocks on the swingarm to make sure they are even

 

[Dregali91]

It did this problem before I even touched anything on it, seller commented and said that it never happened when he had it.

note.. When it was on the trailer on the way home from picking it up ( 3 hrs. ) I had it strapped down pretty hard, the forks were depressed all the way down

 

[Gotwake424]

^ like enough to break a fork seal??

Blackberry 10

 

[Mainjet2001]

Is your rim wobbling or the tire or both? That very well may be your problem.
Strapping it down should not be a problem unless you pulled it hard from the side on the rear wheel.

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[Dregali91]

No fork seals are fine. No leaks

 

[Dregali91]

Is your rim wobbling or the tire or both? That very well may be your problem.
Strapping it down should not be a problem unless you pulled it hard from the side on the rear wheel.

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I sent a strap through the back wheel and then hooked it on both sides on the trailer for like a don't roll back reinforcement, but don't see how that could've hurt anything.

 

[FXCLM5]

grom does have a death wobble around 60mph, maybe going down to 13front the death wobble is around 50mph now? just a guess

 

[Dregali91]

Just changed out the sprocket to a 15t, still have it. I'm stumped

 

[Dregali91]

It just has to be the wheels

 

[Kacz]

I put the bike on a stand and put it in first, I noticed the back wheel wobbling slightly. wheel not true?

This should be where you start to look - you back wheel shouldn't wobble. What kind of wobble are we talking about? As others have said - make sure the rim is true first then move on to the rubber. OR since it does it consistently and you stated it was under warranty I would bring it in and put it on Honda to fix.

It did this problem before I even touched anything on it, seller commented and said that it never happened when he had it.

note.. When it was on the trailer on the way home from picking it up ( 3 hrs. ) I had it strapped down pretty hard, the forks were depressed all the way down

You should not trail anything with the suspension fully compressed. You want it to do it's job even on the trailer. That said the Grom is lightweight enough that I doubt you could have broken anything, but you could have "adjusted" the camber/alignment ever so slightly resulting in a high speed wobble.

grom does have a death wobble around 60mph, maybe going down to 13front the death wobble is around 50mph now? just a guess

More inaccurate bias trolling. Didn't you state in another post the Grom doesn't even do 60? Now it does with a 'death wobble'? Please sell you Grom already and move on...

 

[CiscoSanJose]

Take your rear tire/rim off the grom

Check the rear axle to make sure it is true and straight.

pull the rear sprocket off the rim and check those rubber tamping units "4" for wear or possible defect

Check the wheel bearings by removing the dust seal and putting your finger/thumb on the bearing and rotate the bearing while you put pressure with your finger to see if you feel any unusually hanging of the bearing from not rotating freely. Do that on both bearings on the wheel and the bearing on the rear sprocket hub.

If everything looks and feels ok on the bearings check the rim and tire position and see that you have almost a circular or round perfect fit of the tire/rim.

Last ditch effort is to deflate the rear tire and push the tire off the lip so it is no longer seating snug on the rim and move the tire a quarter turn and re-seat the tire back on the rim and fill with air and put the tire back on the Grom and adjust the chain tension and alignment and torque down the axle bolt to spec and if you still have problems with the rear section tire I would replace the rear tire or have HONDA MC dealer check the Grom out since it is under warranty.

Good Luck

 

[Dregali91]

alright I will give this a shot tomorrow and see if it helps

 

[Dregali91]

I just went out to admire the Grom and I just noticed the rear axle nut (19mm) is gone.... When I tightened the chain I must have forgotten to secure the bolt down... I must have rode a mile without it on, oh shit

 

[Mainjet2001]

i just went out to admire the grom and i just noticed the rear axle nut (19mm) is gone.... When i tightened the chain i must have forgotten to secure the bolt down... I must have rode a mile without it on, oh shit

bingo.......That is your problem....unless you bent the rim or it's out of round or "way" out of balance.
Not sure of others setup, but mine does not have that problem (stock wheel length and wheels) and I have had it at 60 MPH....slightly down hill. :big smile:

PS....your comment "oh shit"......one more bingo....:crazy:. Missing axle nut, not a good situation.

 

[Dregali91]

bingo.......That is your problem....unless you bent the rim or it's out of round or "way" out of balance.
Not sure of others setup, but mine does not have that problem (stock wheel length and wheels) and I have had it at 60 MPH....slightly down hill. :big smile:

PS....your comment "oh shit"......one more bingo....:crazy:. Missing axle nut, not a good situation.

It had the axle nut on it this morning, lmao fuck it I'm taking it to my local dealership its under warranty

 

[The_Grominator]

My first thought was that when the 13t sproket was fitted the rear wheel was never aligned properly this happened to me on my fz1 and had the same symptom of the ride becomming terrible at speed because the rear wheel is not straight.
So after you sort the axle nut issue double check the rear wheel is straight and that the chain has the recommended tension

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