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Discussion Starter · #1 · (Edited)
Have had the new red GT1000 for just over a month now and so far, everything about it has been very nearly perfect.

I noticed just today that the rear wheel alignment mark on the right is between the forth and fifth reference "ticks" on the swing arm, but is aligned with the sixth tick on the left swing arm. Looking vertically at the center of the tire vs. the license plate holder and refeflector, the tire is definately canted slightly right.

The bike handles perfectly, and I'm thinking that this is a factory adjustment.

Do I have a problem here? Should I try to rectify things at my first chain adjustment?

Thanks much, my fellow Ducatisti!

Ride safe, now, hear?
 

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tsmgguy said:
I noticed just today that rear wheel alignment mark on the right is between the forth and fifth reference "ticks" on the swing arm, but is aligned with the sixth tick on the left swing arm. Looking vertically at the center of the tire vs. the license plate holder and refeflector, the tire is definately canted slightly right.

The bike handles perfectly, and I'm thinking that this is a factory adjustment.

Do I have a problem here? Should I try to rectify things at my first chain adjustment?
A couple of things here..

The "ticks" are correctly placed on many bikes, but not all. But using the license plate as a visual indicator is is more likely to be incorrect for several reasons I won't list here. How then can you tell if the alignment is correct?

There are sophisticated tools designed to do this job, but even without them you can get the alignment close enough for street riding.

The easiest is to get down low behind the bike and look past the sprocket up the chain. If no 'crook' is apparent you are close enough. (I'm sure there are plenty of folks who will argue this point. There always is!) ;)

Another approach is, with a friend holding the bike vertical, lay straight (look down 'em to tell) boards parallel to the rear tire and each other on the left and right side of the bike. Now look at the distance between the boards and the front tire on each side. If the distance is equal the alignment is correct.

If it is correct simply note the relationship between the "ticks" on the left and right sides of the swingarm and continue to use that relationship in the future. If it is not correct then align it with any of the above methods and check the "ticks" again.

If the bike feels OK there is no extraordinary pressure to do this this immediately, but why wait? Chain adjustment is something you want to learn to do anyhow, no?

Good luck!

-don
 

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A quick way to check is to measure (with a tape measure, rule, etc.) from the end of the swing arm (same point on both sides) to the center of the axle. In fact, that is how I adjust my chain, I don't use the marks.
 

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My mark on one side is also a tick off from the other side, but I checked it based on Don's notes and the it seems ok.
 

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Discussion Starter · #5 · (Edited)
Don, I knelt down and sighted along the bottom of the chain from rear to front, as you suggested. Sure enough, the rear sprocket appears slightly misaligned with the run of the chain between sprockets, in the direction suggested by the alignment marks.

I'll use your other techniques to check my work, but will start off by lining up the indicators with the marks on the swing arm to see how close these are, looking first for a straight chain run.

I'll be stopping off this evening for a Craftsman six point 30mm socket.

Thanks much!

Ride safe now, hear?

(I love this site!)
 

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Another method if you don't have perfectly straight boards is a long line of string.

Tie around rear tire while bike is on a rear stand. Put in gear and tie it at the back of the wheel 1/3 up the the wheel. Draw it forward so you can kneel down in front of the bike and sight the string relative to the front wheel. You want both sidewalls of the rear tire, on each side, to be touching the string. The extension of that will show tire direction. Do the opposite side. Years ago i had a Dresda swingarm with no notches...you had to align as best you could and paint or etch marks.

John
 

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I'm a low-tech guy at heart, but one of my kids gave me a small laser level and I'm finding it useful for rear wheel alignment. It's magnetic so it'll stick to a steel sprocket or I can clamp it to a non-ferrous sprocket. I know how far the laser is from the base of the level and I can measure the distance from the guaranteed straight (with due apologies to Einstein) laser beam to the front sprocket. Correct for any divergence and the wheel is aligned.

Planets with extreme and angular gravity will require some adjustment, of course.
 

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Way back in my youth, when men were men and British bikes ruled the road, bikes did not have swing arm marks. As discussed, the way to check alignment was with boards or a string. This is made more difficult nowadays because most bikes don't have center stands which means you have to figure out how to hold the bike upright while you check alignment. The other wrinkle (at least to me) is figuring out whether the front wheel is centered before checking alignment. I've always done it by guess and by gosh and by measuring from the end of the (hopefully)centered handlebars to a fixed point on the frame on either side of the bike. HTH
 

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1971TT said:
The other wrinkle (at least to me) is figuring out whether the front wheel is centered before checking alignment. I've always done it by guess and by gosh and by measuring from ....

And always with the assumption that everything forward of the swingarm was straight and true. From a practical sense that is true, but if we were to actually measure the thing (as CompuTrack does) we'd have rude surprises. Twisted frames. Off center triple clamps. Etc. :eek: And that's on new machines.

How many miles of riding consistently on one side of a crowned road does it take for subtle off-centeredness to develop? With a rear tire that is of larger cross section than the front the center line of those tires will move to varying degrees just from crown wear.

No, no one mentions any of this in good company. And that is right. Because from a practical POV it makes little difference.

Of course a logical argument could be made for doing all that we can to make everything Just Right. And perhaps that is true. Or, then again, would the time and expense be more profitably spent getting more riding experience?

(OK, I admit it, I'm weird enough to love this stuff!) :)

-don
 

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In the "good" old days they didn't need high tech stuff like Compu Track. At the Norton factory they'd check Commando frames for trueness by sliding the headstock over a bar they called "the donkey's dick" and if it didn't line up with the rest of the jig they'd whack it until it did.
 

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Discussion Starter · #13 ·
You guys are making my brain hurt!

When I got the bike (last month) I wondered what all of the fuss was about. The new GT1000 handled well, but I'd ridden better. Then came the tire pressure thread. Going from the handbook recommended 32/32 psi to 33f/36r meant an immediate and dramatic handling improvement.

I just finished adjusting the chain and attempting to align the rear wheel, sighting down the chain and using the swing arm marks. The nut is now torqued down to 53ft. lbs. I then took one fast blast down the freeway, followed by a quick whipping of a nearby mountain twisty. Handling is not merely improved; it now borders on the inspired. No, etherial. Wait! Revelational. I'll stop now.

Correcting for Coreolis force during this adjustment was a piece of cake; allowing for the seat stuffing carbon 14 decay rate was a bear! (Turns out that there's an inverse proportion at work here. Sneaky!)

Ride safe, now, hear?

johnrg: Fabulous pic, man! What were the circumstances?
 

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tsmgguy said:
johnrg: Fabulous pic, man! What were the circumstances?
Howard, thanks. The pic was shot at Bridgehampton where I raced with AAMRR, a New England organization. It was 75 Honda 400F SS. The bike had a full 492 Yoshima kit, rsc tach, carillo rods, race cams, head ported, crank balanced, lightened and magnafluxed, bored out carbs, Yoshima race exhaust, Dresda swingarm and Magura clip ons plus oil cooler and drilled out rear drum. I built it on the street and had about 10k miles on it before I began racing. I could blow off stock CB750's on the long Bridge straight but handling wasn't so good so would give back places throughout the races. I dropped a valve after a mis-shift at about 15k RPM's and because of that and the new bikes handling so much better.....I sold it and began racing a brand new 82 GPz550.

The 400F is why I bought the red SC. Easy to see the similarities.

John
 

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If you use the string method, the string should NOT touch the front edge of the rear tire. Just almost. If it touches you cant be sure that its straight.
Make sure the distance from the string to both edges on both sides of the front is similar. Done.
 

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Lars, when I use the string method I find it helpful to use some of the dayglow orange twine that masons use. Also, assuming that the front tire is narrower than the rear, I subtract the width of the front tire from the rear and split the difference so that I know the distance that the string has to be from the side of the front tire for it to show true alignment. Sometimes it's helpful to lay a board on either side of the front tire that is the width of 1/2 the difference of the widths of the two tires as a guide for sighting down the string. No matter how you do it it takes a bit of fiddling because adjusting the rear to bring everything in line is a bit counter intuitive. The old Triumph motorcycle shop manuals actually had a diagram showing how to do this -- they also showed you how to set up your sidecar alignment -- which I guess is not really relevant to most Ducati owners.
 
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