Leaning left

[Robert Haines]

Well I'm sure it's not just me sitting slightly to the left. As heavy as that bike is, my butt shifted over a 1/2 inch doesn't make much difference. To make it track straight without holding on to the handlebars I have to lean so far that I need to hold the tank. If I were to let go, I would fall off sideways... so it's not just sitting on the bike a little to one side.

Also, gyroscopic forces from the shaft or whatever probably aren't causing it since they tend to remain stable unless you push or pull on them. I'm using a throttle lock so I'm not decelerating. It happens when I track straight at a constant speed on a flat surface.

I would be more inclined to think that either the bike is designed with the center of balance to one side (which would be a mistake) or there is a crooked assembly jig at the Yamaha manufacturing plant.

Since it's under warranty, I'm letting my dealer re-align and re-torque the front fork and see where that goes.

 

[saread]

Well I'm sure it's not just me sitting slightly to the left. As heavy as that bike is, my butt shifted over a 1/2 inch doesn't make much difference. To make it track straight without holding on to the handlebars I have to lean so far that I need to hold the tank. If I were to let go, I would fall off sideways... so it's not just sitting on the bike a little to one side.
Also, gyroscopic forces from the shaft or whatever probably aren't causing it since they tend to remain stable unless you push or pull on them. I'm using a throttle lock so I'm not decelerating. It happens when I track straight at a constant speed on a flat surface.

I would be more inclined to think that either the bike is designed with the center of balance to one side (which would be a mistake) or there is a crooked assembly jig at the Yamaha manufacturing plant.

Since it's under warranty, I'm letting my dealer re-align and re-torque the front fork and see where that goes.

Not gyroscopic. Full on torque. The pinion gear is applying a rotational force (torque) to the ring gear that is resisted by the tire/pavement/bike inertia combination. I would expect there to be torque trying to tip the bike over one way or another. Same thing happens in a cage, the engine wants to twist its way out of the mounts. I'm not saying this is the whole answer to what your problem is, just pointing out that with a shaft you shouldn't expect it to not do this.

 

[Scab]

Precession is the term I believe ya'll are looking for.

 

[CAJW]

I had the same problem, local dealer worked on it until he was FJR blue in the face, then when I changed back to my stock windscreen, (with Cal Sci style vents cut in it) the problem went away. Seems the problem was my XL Cal-Sci windscreen as the lean seemed to only rear it's ugly head when it was installed. I've learned to live with it, but riding with my hands on the tank and steering with my knees against the tank takes a little more effort when the Cal -Sci is installed. No... I don't make a habit of riding like that, just found that it's a good way to determine if the bike is tracking straight or not. Also tests your mettle over less than smooth roads. (Don't try this without proper training and a cranial lobotomy first)

 

[Robert Haines]

Not gyroscopic. Full on torque. The pinion gear is applying a rotational force (torque) to the ring gear that is resisted by the tire/pavement/bike inertia combination. I would expect there to be torque trying to tip the bike over one way or another. Same thing happens in a cage, the engine wants to twist its way out of the mounts. I'm not saying this is the whole answer to what your problem is, just pointing out that with a shaft you shouldn't expect it to not do this.

Isn't the shaft of the engine perpendicular with the rear axle? And what I mean to say is that the tranfer of torque from the driveshaft to the rear axle creating a rotational moment will have an equal and opposite rotational moment created by the transfer of torque from the engine to the driveshaft. In a car where driveshaft comes straight out the back of the engine this torque has a tendency to twist the car (see any picture of a drag race where the car's front wheels are off the ground). So I don't believe that's the cause.

I will give it a check though... run it up to 60, put it in neutral, shut the engine off, and coast.

 

[HaulinAshe]

Anybody notice that big honkin' shaft drive thingy hanging off the left side? The wimpy little kickstand, coolant reserve bottle. The battery doesn't counter all that weight.

The bike's not symmetrical, just close. I've got $100 that says roll it up on razorblades and she drops left before the tires go flat. It's just normal. You have to adjust your ass to compensate. And please just hang on to the bars.

 

[meosborn]

The problem could be you. Get the bike up to 20 mph then jump straight off the back. If it goes straight then it is you. If it still leans to left then you know it is the bike. Then again by now you might have figured out that the slightest amount of pressure to either side can cause the bike to move left or right. You would probably be surprised just how far your balance can be off. If you really want to see something interesting get a Wii and try the Wii Fit game. The Balance Board will show just how off your balance is. :headbonk:
In all seriousness I did notice the same thing on my bike. I attributed it to the way I hold myself while riding. If I straighten up and concentrate on the pressure I put on the foot pegs I can keep the bike going straight. I guess what my grandfather used to tell me is true, I am cockeyed.

Enjoy your bike!

:lmaosmiley:

That was awesome! I thought you were serious from the first sentence then the second just caught me off guard. I was looking for a smiley that was shooting milk out it's nose! Who makes these things and can they make one with milk shooting out of it's nose?

 

[Brodie]

Anybody notice that big honkin' shaft drive thingy hanging off the left side? The wimpy little kickstand, coolant reserve bottle. The battery doesn't counter all that weight.
The bike's not symmetrical, just close. I've got $100 that says roll it up on razorblades and she drops left before the tires go flat. It's just normal. You have to adjust your ass to compensate.

I tend to agree, the bike is close to balance but the weight probably resides on the left. Curious though, my Venture Royale had the exact same shaft drive pumpkin and it leaned towards the right when I let go of the handlebars. It wasn't a slight lean either, I had to position myself quite a bit to the left side of the seat to get him to track straight. I went so far as to have the thing Computracked to see if there was an alignment problem with the frame. They found a twist in the swing arm that aimed the rear tyre to the right. If a cutting plane were to be projected from the rear wheel centerline to the front end it was 4 inches to the right of the contact patch. That may have been a contributing factor to the Yamawobble on the beast.

Our bikes are fantastic mounts, wonders of modern engineering. However, they are production models full of manufacturing tolerances that will contribute or detract from the ideal. The method of front end alignment cited in an earlier post that has you removing the caps to your forks tubes and fully collapsing the front end before tightening is about the best way I've heard of to get the alignment as close physically possible. It wouldn't hurt to try it. Balancing out the fork settings - compression, rebound, preload, and even fork oil level will help too. It always pays to keep the rear suspension in good shape and to correct any faults.

In the end it may be as simple as adding ballast to one of the saddle bags to counteract your leftward leaning. Your goal is to be able to take your hands off the handlebars and place them on the fuel tank and have the bike track straight. Any kind of correction performed by your constant input at the handlebars is not to be tolerated. After a while you will feel it reflected in your back and shoulders. The longer the ride the more of a pain in your back side.

Good luck with it, and let us know the outcome.

And please just hang on to the bars.

And no! I don't care to hang on to the bars, that is how unnecessary and undesirable steering inputs occurr - but that's another discussion

Brodie

 

[wildman]

I know a lot of folks have said their bikes are the same, pull to the left etc. etc. Not mine. 2006 with 15k miles. I can ride for miles with no hands, steering by just leaning my head one way or the other. May not be the safest, but sure is comfy when your slabbin.

wildman

 

[Robert Haines]

Anybody notice that big honkin' shaft drive thingy hanging off the left side? The wimpy little kickstand, coolant reserve bottle. The battery doesn't counter all that weight.
The bike's not symmetrical, just close. I've got $100 that says roll it up on razorblades and she drops left before the tires go flat. It's just normal. You have to adjust your ass to compensate. And please just hang on to the bars.

You may be right. But I would hope that the Yamaha design engineers took all that into consideration when they designed the bike. I doubt that balanced it "by chance".

 

[gaidaros]

Thank you all for your answers.