My local dealer had an '08 Ultra on the showroom floor last Saturday, and I noticed something interesting. The top turnbuckle has been relocated from between the cylinders under the tank, where it's been since I can remember, to forward of the front head, bolted to the right downtube. I wonder if this may be an effort to address the wobble that is reportedly fixed by products like True-Track, Ride-Str8, etc. By locating it in front instead of the rear, I wonder if it would be as effective? Or, maybe they relocated it because the tank was so big there wasn't room under the tank for the turnbuckle.

 

I'd bet on the tank being bigger necessitated the change to the mounting point

 

OK I will have to take the heat but what is a turnbuckle?

 

top engine motor mount

 

A turnbuckle is a device for tensioning wires, ropes, or tie-rods. It escapes me just now what the technical name is for the adjustable links we're pondering at the moment. But I've been known to call it a "turnbuckle" myself.

I've mused about this already in several other threads/posts and vote for the cause of displacement being part of that extra gallon of fuel. I'm also skeptical whether its placement lower down and further from the rear mount will be as effectual as the former location. I also wonder if it being bound to only one jug instead of both is the best situation...

 

That devise is there to limit motor vibration. It works fairly well so far. I just picked up my 08 last Thursday

 

If you were to grab the top and bottom of the rear tire and try to twist it sideways in the frame its motion would be restricted by the swingarm/rear engine mounts in the frame below the passenger footrests and by that toggle in harmony with the one at the front mount. When the toggle was up between the jugs it pretty much held the top-most part of the engine from moving sideways so that would mean your twisting on the rear tire, to result in any movement, would require the swingarm pivot shaft to move side-to-side in the frame as well as twist within its mounts. Some say that's something that happens fairly readily and is cured by the True-Trac, et al.

With the upper toggle now lower in height it would be easier for the engine/tranny/swingarm to pivot at that new point with your twisting motion on the rear tire. Think about it. If the toggle were moved to the same height as the front mount toggle you'd really be able to twist the drivetrain assembly. The ease of doing so would linearly decrease the higher you move the toggle from there. With the best snubbing action being at the highest point possible and the worst at the lowest, the new location has to fall somewhere in between.

I'd bet the engineers had a conniption over that sixth gallon the stylists insisted had to go somewhere besides so much up and out.

 

I'm going to guess that you're an engineer as well- Good description-

 

Not really (at least not officially, certainly not professionally). Thanks.

I should have said "twist it about its vertical axis" instead of "twist it sideways". Twisting was the main thought and not pushing/pulling both top and bottom in the same direction at the same time, as "sideways" may suggest. (though successful sideways motion would net a "twist", at least with the older "top" link location

There are other factors to the whole line of thought, though. First would be to consider the percentage of height of the new vs. old positions perpendicular to a line drawn through the swingarm pivot and the front mount link. In conjunction with that, the question arises as to whether the new stationary mount point offers better or worse sideways rigidity within the frame itself. If the new point flexes the frame less than the old did that would effectively increase its height in comparison; more flex would net an effective height decrease. I don't know how much flex the frames actually have in either location. Probably not enough to worry about.

Also, there's the consideration of whether spreading the force to both cylinder heads vs. only one is any kind of a factor in terms of both flexibility and longevity of the head(s)/cylinder(s)/case it(their)self, and the junctions.

Again, probably not really all that much difference in the big picture.

It may well be that the engineers had worked this all out as an improvement beforehand, then went to the other departments saying they'd freed up some space along the frame backbone for any kind of use those other folks might want. Maybe they'd discovered that a sideways force on the rear tire, with the steering head between the front and top links, caused the steering head to twist in an unfavorable way, thus magnifying the effect. Who knows?

I'm not trying to be an alarmist and I'm certainly not bemoaning the fact that I just recently bought an '07 wishing I'd held out for an '08 instead. If I had an '08 I'd be tickled pink; just as I am with my '07.

My mind naturally goes places like this and I feel it's worth discussing and that this is a good place to do it. Besides, it's a good change of pace from debating the merits of dino vs. lab oil; tire tread patterns; muffler sound; etc., right?
Not to suggest those are totally without merit themselves, of course.