Death wobble

[Joast]

Are these 2 stroke bikes prone to death wobble? (I have stock 66/80 2 stoke on a Schwinn cruiser).
Sunday I was running about 25mph down a smooth, flat blacktop and it started to feel like
a death wobble shaking in the handlebars/front end (all the bar bolts and front end bolts are tight).
It finally stopped after I got the speed reduced down to about 15-18 or so. Once I got back in town, I rode it
for about 20 minutes or so at various speeds and then it seemed fine. It was pretty windy outside
but this seemed different than just wind blowing. I have had a couple death wobbles on my scooter before, and this felt just like that.
Wondering what could have caused it? Thanks John

 

[Sidewinder Jerry]

Are these 2 stroke bikes prone to death wobble? (I have stock 66/80 2 stoke on a Schwinn cruiser).
Sunday I was running about 25mph down a smooth, flat blacktop and it started to feel like
a death wobble shaking in the handlebars/front end (all the bar bolts and front end bolts are tight).
It finally stopped after I got the speed reduced down to about 15-18 or so. Once I got back in town, I rode it
for about 20 minutes or so at various speeds and then it seemed fine. It was pretty windy outside
but this seemed different than just wind blowing. I have had a couple death wobbles on my scooter before, and this felt just like that.
Wondering what could have caused it? Thanks John

Some bikes and tires simply aren't designed for high speeds.

 

[FrizzleFried]

Hard to imagine any properly built bike getting "speed wobbles" at 25mph...

 

[darwin]

Same with M/C's. 100 different opinions on why it happens. Some models are more prone to develop it though. Forks, tires, weight distribution are all blamed, frame geometry too but never proved by science.

 

[Sidewinder Jerry]

Same with M/C's. 100 different opinions on why it happens. Some models are more prone to develop it though. Forks, tires, weight distribution are all blamed, frame geometry too but never proved by science.

More than likely it's several contributing factors and not just an individual thing causing it.

The primary things to check is wobble inside of the Head Tube, Wheel Axles wobble and Wheel Trueness. If all these seem good you can try different air pressure adjustments on the tires. Does it only occur on certain roads? If still there, after doing all these checks; try a different type of tire. If you still have it; then it's the frame geometry and you're stuck at a certain max speed.

 

[Chainlube]

Just hitting a rock on the road can cause a speed wobble.

 

[Sidewinder Jerry]

Just hitting a rock on the road can cause a speed wobble.

I think what many don't realize is how much things can loosen up after a couple months of riding. I do a tightness check once a week.

 

[FrizzleFried]

Once a week? I check that vital components are tight EVERY RIDE (vital components = engine mount ... front and back rim ... and brake system).

 

[CENTURION]

I would check the play in your front and rear wheel bearings, and motor mount tightness. Take a flashlight and inspect all the welds just to be safe. I've had the head tube loosen up after 500 or so miles as well, just tighten the nut. Just me, but I wouldn't ride the thing until a "death wobble" was sorted. Do a good shakedown and I'll bet you find something loose.

 

[Sidewinder Jerry]

Once a week? I check that vital components are tight EVERY RIDE (vital components = engine mount ... front and back rim ... and brake system).

When I'm talking about a tightness check that means a wrench, socket, or alan on everything that fastens.