5th Gear Vibration

[EBT531]

I have a 05 400ex thats stock. At the very top of 5th gear the rear tires start to vibrate pretty bad. I dont notice it at any other time except when at top speed. Any ideas whats wrong? A friend said maybe a slight bend in the rear axle, but I think I'd notice that more then just the top of 5th. I know people dont balance these tires, could that be it? Also I dont think here is any fix-a-flat or slime in them. (I am going to check later)

Update: Rear sprocket is bent, no damage to skid plate. Any idea what could have happened?

[EXevan91]

lol your on the road thats you #1 prblem those tires arnt made for it it most likely the tires and or u could have a tweaked axle or wheels bent wheels really show when flying down the road.

[EBT531]

If you mean a reg. road, no. Its a very wide and smooth dirt trail/road.

[firefighterjosh]

Its prally a bent rim. Jack your quad up off the ground. Put it in gear and watch the rear tires. You should be able to tell if the rims are bent or if it is the rear axle. If they are strait spin the front tires and check for wobble, if the front is strait you might have a bent a-arm or something. Hope this helped

[EBT531]

I am confident thats its in the rear and not the front. I know the front rims are good and it spins straight. Plus I really feel it in the rear. I will jack it up tomorrow and see how the rear looks.

[EBT531]

Ok I checked the rear and the axle looks good as do the rims BUT the freaking rear sprocket is bent! How does that happen?? Also I am guessing if I replace the sprocket I might as well replace the thing it bolts to in order to make sure thats not bent as well right?

[johnsls]

If you don't have it already and your riding trails I would suggest a Full skid plate and the rear skid plate too.

I have the PRM read skid plate,,, you just can't beat it,, ITS AWESOME.

As far as what to replace you should replace anything that you think might be bent..
You know what they say measure twice cut once.

[EBT531]

I have a rear skid plate and dont see any damage on it suggesting I hit something. Just cant figure out what would bend this other then collision.