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Discussion Starter #1
Just received the Jan 03 issue of Motorcycle Consumer News (MCN).

They have the start of a series on FLT models showing how to align front and rear tires to solve some of the high speed handling problems.
 

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EvilMonger
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Ed, anyway you can Email me the article, or snail mail me a photocopy ???

I am interested in high-speed as you know !!!!!
 

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Just bad
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Interesting. My Dad developed and patented a cycle alignment tool in the late 70s and spent a couple of seasons with the racing teams at Riverside. It never took off because eyeballs and string-lines are a lot cheaper and easier to come by. On the superbikes of the day, that alignment would just about eliminate wobbles. He's still got a 74 Kawi Z1-A that I have run well into the 3-digits with no instability.

Now I just have to remember to borrow his damn tool next time I'm over there. My 01 RC gets sorta unstable over 70mph and I need to check that alignment. On my last trip to the dealer (3rd try warranty on primary cover gasket) I mentioned a slight wobble/instability. Amazingly they returned it with no problems noted on the test drive. Considering my own experience in the flat-rate pay world of auto repair - I literally dangled a 5-6 hour carrot out there for them to sell me an alignment and/or steering head adjustment. Too bad for them. Now I'll just do what I shoulda done in the first place. Borrow Dad's tool and just do it my damn self :) Now where the f*ck did I put those crowfoot wrenches???
 

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MCN is certainly a reputable source.

Let's see how the article pans out.

There are those who deny that the touring machines have (or had) a
wobble problem.
 

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Discussion Starter #5
Thealien said:
Ed, anyway you can Email me the article, or snail mail me a photocopy ???

I am interested in high-speed as you know !!!!!
Mark:
I don't have a scanner but will see if I can get it done in town. They have a web site but article probably will not be posted for quite a while.

http://www.mcnews.com/mcnews/index.htm

I'll post back tonight about what I can get. I've subscribed to MCN for years. It's not a Harley oriented rag just motorcycles in general. However, they take no advertising from any motorcycling companies so their tests, studies, etc. are mostly unbiased. Lots of good info in the rag. That's where I first read about the Mini-Ratchet kit in 96.
 

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Discussion Starter #6
pasadenajim said:
MCN is certainly a reputable source.

Let's see how the article pans out.

There are those who deny that the touring machines have (or had) a
wobble problem.
Well, I personally haven't had a problem but then I normally never travel much past 75 unless passing. I just wonder how many people have seen the hint in the owner's manual that recommends not exceeding 80 MPH if riding two up. I'm sure that also applies to rider only with lots of luggage. I do tend to slow down when riding two up and pulling my little one wheel trailer, too.
 

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I usually run 75 on the interstates but sometimes run up to 85 and 90 to get past a group of cars/trucks runnin' the same speed as I am. My '02 Ultra is rock solid traveling two up with a weekends worth of clothes in a duffel strapped on the luggage rack.

My old '00 Ultra would get a little skittish in the 85 to 90 area ...
 

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Also ... important to keep the air at the right level in the rear air shock. Harley has a nice little pump with gauge attached that makes it very easy to adjust. Usually run 10 lbs. of pressure when two up with luggage. Actually, I just leave 10 lbs. in all the time. Seems fine solo also ... Factory setting when I received the bike was 6 lbs. Those 4 lbs make all the difference in the ride also. Smooths out everything and keeps it from bottoming out with a load.
 

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80MPH to 90MPH daily. No wobbles to speak off.
I just use a Vernier Caliper and measure the distance from the end of the swing arm to the Axle, same both sides, seems to work.
 

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Discussion Starter #10 (Edited)
harleyhog said:
80MPH to 90MPH daily. No wobbles to speak off.
I just use a Vernier Caliper and measure the distance from the end of the swing arm to the Axle, same both sides, seems to work.
That's good you don't have any problems. However, you are just measuring the relationship of the rear tire to the swingarm. I also think you would get a much more accurate measurement if you measured from the center point of the swingarm bolt to the center point of the rear axle (see service manual). I also think you have two small holes about 6-8 inches(i know you don't have inches over there but that's all I know :D) to the front of the rear axle. These can also be used to measure alignment. The article in MCN is talking about aligning the track of the front and rear tire using the lower front stabilizer which has been proven to be a source of high speed wobbles.
 

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Have to wait and see after I read it.
At one time they had some dude post the procedure to align the wheels with two laser levels (the home version of a readily available machine)
The dude just made a basic and fundamental mistake.
If it is repeated in the article I tell you what it was.
 

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I just read the MCN article today. thing that I didn't quite understand was they spoke of offset, said adjusting the front turnbuckle corrected that but to my way of thinking the front turnbuckle pulls the front of the motor away from the centerline of the bike which moves the rear wheel farther from being parallel to the centerline of the bike.

unless they were getting the offset corrected first and then using the rear axle adjusters to get the front and rear wheel parallel to each other I dont see how it would work.

ideally, you want the wheels on the same centerline, parallel and perpendicular to the ground. MCN was not very specific, I dont think they got the story correct but WTF do I know.
 

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That's the flaw in their thinking.
The bike is designed with offset, ie the plane of the rear wheel is parallel but not superimposed to the plane of front wheel and the plane of the centerline of the bike when the bike is travelling straight.

If you go and move the powertrain in such a way that the planes of the front and rear wheel are not only parallel but superimposed you may have eliminated the offset but the plane of the wheels is no longer going to be parallel to the centerline of the bike.

Happy dogtracking. :D


They have some capable people, may well be that by eliminating the offset in this unorthodox manner (and causing the dogtracking) they achieve whatever handling condition they are after. I just don't see how you can call it aligning the bike when the damn thing is going down the road sideways.
 

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Hippo, I see the engine,tranny and swingarm as one assembly. anything that pulls that assembly out of parallel with the centerline of the bike is not going to be easily corrected by their oversimplified method of alignment. they made it seem like adjusting the front turnbuckle somehow makes that whole assembly move when to my uneducated and untrained eyeIjust see them moving one end of the chassis by that particular adjustment. guess I saw the same flaw as you.

friggin magazines, buy em and you get just enuf info to futz U up!
 

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Engine, gearbox and swingarm for all practical purposes are one assembly on the FLT's. The front lower link causes the assembly to PIVOT in the cleveblocks when adjusted.
It isn't going to cause a parallel motion of the centerline plane of the powertrain in relationship to the centerline plane of the frame anytime soon.
 

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This scan came from April issue
 

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Sorry for the larger size
 

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Discussion Starter #18
Hippo:
Don't claim to be an expert by any means but maybe I'm missing something here or don't understand. First of all, HD service manuals for FLT allude to the fact that adjusting the bottom stabilizer does the horizontal alignment. I quote "Place a straightedge along each side of the rear wheel and adjust the bottom stabilizer so that the front wheel is centered between the straightedges". Doesn't this imply that the front and rear wheels run in the same track? It doesn't appear that HD wants any offset. Are they wrong? Then the top stabilizer is adjusted to provide for vertical alignment. The article in MCN talks to the horizontal alignment only in this issue. The next article in next month issue will address the vertical alignment although MCN says they will use a Computrack to do a precision three-demensional alignment.

Tell me what I'm not understanding here.
 

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Well I'm not a chassis engineer either, just a old boy with a little horse sense, but if we stipulate that the bikes have some offset (on this everyone seems to agree) and you enter the variables into a CAD program you come out with the same result every time no matter how you move it around.
Let me read the article and maybe there is something in there that changes my mind, have not checked the mailbox in a couple of days maybe the mag came.
Anyones guess what the service manual means, you know how Harley's instructions are at times.

On the one thing we agree so far is that a Computrack is the only way to properly align a bike.
 

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The way you might align a offset bike with straight edges or strings (or a laser for that matter) is that if you extend them from the rear wheel forward with the front wheel exactly straight ahead and in line with the bike centerline you would have four dimensions between whatever you use to measure and the wheel, two on each side one towards the front and one towards the rear. When the two dimensions on one side and the two dimensions on the other side are equal the planes of the wheels and the centerline of the bike are all parallel. The right and left side dimensions would differ exactly by the amount the rear wheel is offset.
 
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