R3 pulling to the left????

[Torch]

My friend in Arizona just picked a gray R3 with just about everything on it. He says when he does 15 or so mph it pulls to the left when he lets go of the bars. Besides telling him not to let go and the possibility of the crown in the road doing it what could cause this? Bike has never been crashed or dropped. He knows about it torquing to the right on a throttle blip..Any ideas

 

[RiderRocketman]

It is normal for the Rocket to lean when revv'd and you're on a level plane because of the large main crank gear mounted crosswise in the engine case (spinning in the left/right plane like a clock face sitting in front of you). Much of that spinning force is cancelled by the clutch and tranny spinning in the opposite direction but it isn't a complete cancellation so you still have a tendency to lean when that big crank gear is spinning fast.

If the engine crank forces or road cambor are not what your friend is experiencing then he could have a wheel alignment problem. Probably no problem though so I'd also recommend not going hands free on a speeding Rocket. :lol:

 

[RiderRocketman]

Hey, Slarti and Ogre, I distinctly remember explaining the crank forces in more detail before but the original thread is lost. I think you need to tell the admins to turn off that auto-pruning stuff so we don't keep losing content. :wink:

 

[REGULATOR]

Not too mention its windy as heck out here in AZ these days!!!

 

[TurboFan]

Try the same 15 mph in a couple of different gears. The motor has enough torque to pull 3'rd on a flat level parking lot at a steady 15 mph (I think) If it will, and engine gyroscopic forces are to blame then the effect would be much much less at lower RPM. If it is unchanged, (and I would try shifting to neutral and coasting once also) then it is alignment for sure. One other thought, is there any unusual tread wear? If the bike spent the last 4,000 miles on an oval or commuting in the slow lane of a road with a very high crown,... OK I'm reaching a little here, but do check the tires.
Martin

 

[lonerider]

Check tyre pressure, voice of embarrassed experience!!

 

[dragline708]

deleted

 

[Ogre]

Hey, Slarti and Ogre, I distinctly remember explaining the crank forces in more detail before but the original thread is lost. I think you need to tell the admins to turn off that auto-pruning stuff so we don't keep losing content. :wink:

I agree--I will try to see if we can do something............

 

[Ogre]

My friend in Arizona just picked a gray R3 with just about everything on it. He says when he does 15 or so mph it pulls to the left when he lets go of the bars. Besides telling him not to let go and the possibility of the crown in the road doing it what could cause this? Bike has never been crashed or dropped. He knows about it torquing to the right on a throttle blip..Any ideas

1. Don't take hands off the bars at 15mph.

2. Does it pull left at 15 and above? Does it pull left at normal highway speeds?

3. It sounds like a combination of 2 things to me (based on very little input as to what the problem really is and how the bike is set up.

The bike with fresh new tires will feel more reaction to the crown of the road. After the tire "wears in" that will become less noticeable. Then when you finally put a new tire on, you will feel it again.

Also since you say the bike has a lot of accessories, I am suspecting that there may be an imbalance in the weighting. Adjusting the weight from left to right in saddlebag contents may do the trick. It could also be the posture of the rider. We are all put together a bit different. They way one rider sits/fits a bike will vary with another as far as balance. (one arm shorter than the other etc.)

If he balances out the bike with accessories and body position and it still pulls at highway speeds, then there is a real problem someplace.

 

[TurboFan]

Wow, I didn't realize it sounded like I was advocating letting go the bars at slow speed. A light feel yes, but not letting go. Probably a moot point since I think Ogre is right on with the weight issue.