Severe vibration at top speed and down hill please help

[loadingup80]

I have a 50cc engine kit and it operates good at medium to low speeds. When it reaches top speed it vibrates through my handlebars down my legs and it's a severe vibration. Also when going downhill the vibration is even worse. It's there anything anyone can think of why this is happening?

 

[GW's Motorized]

Are your wheel bearings in the rear tight? After I first built my bike the rear wheel bearings weren't all the way tight. My bike would wobble bad above 15 mph.

Another thing to check is the motor mounts. If they aren't all the way tight it can have a bad vibration

 

[loadingup80]

Are your wheel bearings in the rear tight? After I first built my bike the rear wheel bearings weren't all the way tight. My bike would wobble bad above 15 mph.

Another thing to check is the motor mounts. If they aren't all the way tight it can have a bad vibration

The wheel bearings in the rear are tight. I've tightened everything. I'll check the mount.

 

[darwin]

I hate the word "TIGHT" for bearings, not the right word to me. Seems "SET" is a better word. Just need to be installed with no play in the axle, horizontally or vertically.

 

[GW's Motorized]

I hate the word "TIGHT" for bearings, not the right word to me. Seems "SET" is a better word. Just need to be installed with no play in the axle, horizontally or vertically.

Thanks, that's what I meant

 

[DAMIEN1307]

I have a 50cc engine kit and it operates good at medium to low speeds. When it reaches top speed it vibrates through my handlebars down my legs and it's a severe vibration. Also when going downhill the vibration is even worse. It's there anything anyone can think of why this is happening?

Some pics of your build would come in handy as we will be able to see if there are any inherent flaws that might be easily corrected to help minimise your vibration problems.

 

[ImpulseRocket]

Are you coasting downhill without pulling in the clutch and keeping the engine rpms high? If so, I highly recommend you stop doing that before you seize the engine going downhill at high speed due to a lack of lubrication, and crash when the wheel locks up on you. 2 strokes don't do engine braking

 

[Sidewinder Jerry]

If it isn't an engine issue then it's a wheel/tire issue. Some wheels and tires can't handle high speeds. You'll notice it even more if you don't use suspension systems

 

[darwin]

Some cheap bike tires can be out of round fully inflated. Spinning the tire and looking straight on and from the side is the only way to tell. Not being seated properly around the bead can do it too.

 

[Chainlube]

. Not being seated properly around the bead can do it too.

Oh God, I've done that too. I even pump up my tires with a hand pump.