i have an 08 650i with 45 hrs on it, stock tires, no upgrades.
When i am driving the bars will all of a sudden jerk to the left. It feels the same as when your wheels fall into an ice rut, however this happens on smooth hard pack and smooth gravel . The pull happens quite often, it seems to happen when I am turning to the right. My air pressures are the same, and I have not felt it when i am in 4 wheel drive.

please help.

 

i am gonna try dropping down to 4 psi, from 5. It just feels like that left tire digs in for a half second and lets go.

 

Purely speculation, so take it for what it is worth...

Have you checked all of the steering components? A loose tie rod end could cause this, I think. If the toe in condition suddenly changes, that would definitely be felt in the steering and would probably show up in turns.

Another thing would be to check that the front end is unlocking properly when not in 4-wheel drive mode. If one side engages and the other doesn't (don't know if that is possible in these models) then it could cause drag on the one side and not the other.

Also, check the front brakes/rotors. If one grabs and the other doesn't, that will show up as a pull to the side that is applying more braking force.

All of this is based on experience with cars, but I think some of these things could be applicable here as well.

Good luck!

 

Any unusual noises associated with this? Grinding? Popping? Clicking?

It could be many things. It sounds like you already looked at the obvious (tire pressures, tie rod ends, steering components, etc). I agree with what 0010 said. Check the front diff and make sure nothing is wrong there. Don't forget about ball joints and a-arms. I would also check your CV joints on that side and see if you have a bad one. When my boot popped off and the joint filled with dirt and dust it grinded and pulled to that side. Look for a ripped or popped off boot.

Good luck.

 

check for loose cv joints or something floating in disc brake caliper.

 

post more detail in your next post, sound especially. when u turn, does the jerk come from mabe an exceleration increase or decrease? my old trike used to do tht but it was that the throttel would stick a lil when id turn left. same for my 250 now. new model though, could be throttle, keep an open mind to the diagnostic

 

dont hear any sounds when it happens, it happens when i accelerate, when i am slowing down, and when i am just cruising along. It happens quite regularly, and it is quite annoying. I wasn't on a 4 wheeler in 20 years and when i got my brute ( a month ago ), I was amazed at how well it steered and handled. I don't know when it started pulling because i thought it was being caused by trail ruts. Now i feel like i am fighting the steering. I have an appt on monday to get it checked out.

 

RADIATION74, any update? What was the problem? Enquiring minds want to know!

Thanks!

 

This sounds like a pulled out axle shaft, or more likley a broken cv joint. I also agree with the previous post about the brakes hanging up.Just thought about the post on the tie rod also highly posible it could be bent and is more pronounced on turn seeing how i thing you said no noise, hope these good starting points from all help.

 

boot clamp fell off, cv joint got wrecked. set me back 160 bucks, weird thing is, it was the right side. works like new, for now.