vibration issue

[Aircooled]

Hi Guys,
I have a question regarding vibration. When I get on the bike and gas it, it tends to vibrate up front until it smooths out.
Has anyone experienced this, and could it be as simple as a wheel, or wheels being out of balance....or a a tire out of round. I'm just trying to apply my automotive knowledge here. Another thought was perhaps the engine is out of balance.
It's a basic Motovox MBX10 with the stock 79cc engine...nothing fancy, no mods done.
Thanks for listening.

Jack

 

[Raskin]

Tighten your neck bolt..that's something I've had that needs looking at ever 6-8 rides when do basic maintenance unless it's clutch shutter.blow clutch out or take apart clutch and use very fine sand paper to get residue out of bell ..those stock gear ratio really too high for heavy riders may shutter anyway on giddyyap

 

[Aircooled]

Thanks for reply, Mr. Raskin.
I had re-tightened the neck bolt. I try not to over tighten it. I don't want to put too much stress on the bearings. I have had it apart and tried packing grease into the neck and shaft.

However,you've brought out a good point regarding the clutch. I'll look into that. Thanks for the tip on clutch maintenance.
The gearing is a stock 75 tooth rear sprocket, which should be better for low end power. I'm around 160 lbs, no heavy weight by any means.
Thank you sir, I appreciate it.

 

[mlanzoni]

Check the frame for any cracks(?) Good luck.

 

[Aircooled]

Check the frame for any cracks(?) Good luck.

Thanks for your reply. I've pretty much looked the frame over as I was prepping it for paint. It could be attributed to clutch shutter as Mr >Raskin suggested.
Maybe it's time to install that Predator 6.5 hp engine. :wink:

 

[Aircooled]

I'm still plagued with the frontend vibration problem. Is it common problem on these particular bikes, and has anyone come up with a solution/ remedy? I figured I'd like to eliminate this issue before adding a more powerful powerplant.
Would an MBX11 fork with front shocks help in this case?
I'm all ears..

 

[Fatboy04]

More power (upgrade to 212 cc)

 

[Aircooled]

More power (upgrade to 212 cc)

So you're saying that by adding more power it would eliminate, or lessen the vibration. Hmmm...interesting.
It is rather annoying, I must say.

 

[Bumblebee2]

So you're saying that by adding more power it would eliminate, or lessen the vibration. Hmmm...interesting.
It is rather annoying, I must say.

A 212 Predator in a Motovox. That would get you to the speed where everything starts to vibrate much faster.

That's the thing I have been realizing, everything is _almost_ good enough. On both of mine everything wobbles.

 

[Raskin]

sit on the bike turn your handle bars to the stop and push a little more.. do this both ways.if it makes a slight move in the neck bolt when against the stop when you add pressure it is too loose or bearings/sleeve in neck bad

 

[Aircooled]

sit on the bike turn your handle bars to the stop and push a little more.. do this both ways.if it makes a slight move in the neck bolt when against the stop when you add pressure it is too loose or bearings/sleeve in neck bad

Thanks again for your advice and input, Mr. Raskin.
I have checked the neck bearings, they seem good...turn smoothly, no choppiness or ratcheting feeling.
It does seem that everytime I take the bike out, I have to re-tighten the neck bolt.
I will replace the locknut.
I wonder if it's feasible to replace the neck bearings with a bronze bushing. A bushing long enough to cover the length of the steering tube. I'm just thinking out loud.

 

[Raskin]

been thinking of getting these for neck bolt nuts..I use them on other things,they stay tight better..guess available with these thread type..unsure..I'm gonna take neck nut with me to hardware store and see next week

 

[Aircooled]

Actually, what's on there now is a similar type lock nut.., but I think it's lost it's locking ability...probably due to poor quality hardware.
I've been planning on replacing that nut and the two axle nuts for the same reason.
Usually with a good functioning lock nut, you'll feel some resistance when you're snugging it down. These nuts feel like you're tightening down a regular non-locking nut. I guess that's an indication that the nuts have outlived their usefulness.
I think they can be gotten at Lowes, HomeDepot, and an Ace hardware.