Vibrations of death

[bare bones]

Hi all!
I have a Grubee Skyhawk "80" that has come down with a case of the Vibrations of death. It has been a wonderful little engine until now. It has around 400 miles on it. At around mid to 3/4 throttle there is now crazy vibration that has become worse over the past week. I can't hit as high of a top speed anymore and there is a point during acceleration (that is repeatable) where the engine tops out and then becomes slightly weaker. Is my engine vibrating because it is out of balance now? Is there any way to cure my little china girl?

 

[Venice Motor Bikes]

make sure your chain isn't flopping around & slapping the tire?

 

[bare bones]

Thanks for the reply.......no floppy chain here.........It is just really strange how the vibrations have basically come out of no where. I will do a second once over to see if anything else could be loose. Can the clutch cause vibration like this if it isn't aligned correctly?

 

[wildemere]

Carbon buildup on piston?

Loose or broken mounts?

My bet its one of the above.

 

[bare bones]

All the mounts are good. I have not checked for carbon build up........ I will do that today

 

[rmeloy34]

whats a good way to clean that buildup?

 

[Kevlarr]

There are some products out there that clean carbon buildup out of an engine but if you have some ATF laying around an ounce or so added to your gas will clean the carbon right out and it'll get rid of the mosquitoes in the neighborhood too.

I've seen people drizzle it down the carb on a car but after a few seconds you couldn't see them anymore.

 

[bare bones]

How about Sea Foam Green?

 

[bare bones]

Thanks for all the good tips! I changed out the stock mounts for steel mounts and really snugged them up. At the same time I took off the exhaust and it was kinda clogged so I gave it a good cleaning and knocked all the crud out. The vibrations is down to around 20% of what it was and there is no bogging at top end (I imagine that the clean exhaust helped here). Now the bike is not uncomfortable to ride!!!! WoooooooHOOOO