Topic: AM I CRAZY INSANE?, OR IS THE REAR WHEEL NOT DEAD CENTER..

[chippyfive50]

I JUST built new wheels for my 500(frame),  and used the hubs off of a 550.  The front is dead center and straight, but the rear seems to be "dished" about an 1/8th inch to the right, (away from the chain).   I built these somewhat "blind" since I did not have to disassemble my originals, and had no "bench measurements" per se.  My new rear rim measures(as best as I can)  about an 1/8" off to the right. So I put my stock wheel on and it is slightly off too, then I looked @ my 750, and IT is slightly off center the same way. I know my eyes (and imprecise measuring methods) might be playing tricks on me, but they are all consistently "right" to some degree.  I know an 1/8 is small, but shouldn't the rim be DEAD center?, and now would be the time to fix it.   OR AM I CRAZY, and there is a slight offset.  OR IS IT ALL AN ILLUSION (OR DELUSION)

[wheelie]

As a bicycle mechanic and shop owner, I've built several hundred wheels and it's very easy and common to correct a mis-dished wheel. Just tighten the drive side spokes 1/4 turn after loosening the non-drive side spokes the same.  This will bring the whole rim over a bit. re-measure and repeat if necessary.

good luck.

[chippyfive50]

thanks wheelie,
but I suppose the direct question is that the rear wheel should indeed BE dead center, that sounds stupid to me when I ask it,
but given that my other 2 wheels seem off  as well, I thought I would make sure...

[volthause]

I remember reading a topic on this not too long ago. The end result was that the wheel does NOT appear centered in the swingarm, but is, in fact, on the centerline of the frame.

For piece of mind, take the tank and seat off the bike and run a piece of string down the backbone of the bike. I think you'll find the rear wheel is where it is "supposed" to be.

[Hop on a Honda]

Wheels.
Wheelie is right. But there is such a thing as parallax error. It's a most visual mistake.
As the man says take the tank off & seat maybe, then using a stringline and some heavy weights to hold the strings. Place the string around the front wheel at rim level on either side so as the two pieces of the string go back on either side of the rear wheel.
Now center the front wheel and check for the string to be alongside both sides of the front tire and clamp the string to the front tread.
When the string is pulled tight at the rear the gap should be zero on both sides of the tire.
If for instance the front wheel is twisted one way or the other a gap will emerge from the string near both front and rear tires. It is imperative that the front wheel is centered (Steering lock work?)  Check the rear tire again to see if the string is bias to either side.Adjust.
The objective is to make sure that the drive sprocket and the rear wheel sprocket are aligned via the chain. This will then assume that the frame is straight and that the engine is aligned as it should have been on installation.,
Some times I get a piece of wood doweling 10" long, and put it in between the rear spokes, feet on rear foot pegs,pull the whole rear wheel assembally and use it as a unbias handle to pull the rear wheel tight regardless of the tightness of the chain. Wife comes in handy as 2IC of axle spanner!
Spin the wheel to give indication of freewheeling with out binding of chain.IF it works the use the axle adjusters to fine tune the position. Make sure that the wheel will rotate easily and with out being to tight on the chain.Tighten the axle nut temporarily untill your satisified that the wheel is not being bias to either side.
I had a loose rear wheel sprocket recently,(All four nuts) it gave a very bad indication of the rear wheel being out of aglinment and the engine about to explode.
If all fails go 50/50 the call a friend

Dave

[volthause]

here's that post i was talking about

http://www.sohc4.us/forums/index.php?topic=7764.msg71776#msg71776

[eurban]

The rear wheel rim should be exactly centered between the left and right spoke mounting flanges on the rim.  If your rim is not centered over the hub then you should correct it.  However, you may find (as I did on my 750 and described in my posts in the thread that was mentioned previously) that your rear wheel is not centered in between the swing arm,arms but you should find that it is centered on the frame.  Basically on my 78K, Honda shifted the swingarm and shock assembly to the left about 1/8th of an inch and then shifted the wheel about the same amount back to the right in the swing arm, ending up with a rear wheel that is just about centered on centerline formed by the backbone of the frame.  Good luck

[chippyfive50]

here's that post i was talking about
http://www.sohc4.us/forums/index.php?topic=7764.msg71776#msg71776

THANKS a lot fells, I messed with it last night for another hour or so., and after about 4 beers it looked straighter.
I clamped a torpedo level to the rear frame member to establish  reference, then employed some nice dial calipers, and got it spot on center of the hub.
That post makes me feel like I am not crazy for posting this, what seemed like a STUPID question. I will now let my stock spacers work out the details!!
TIME TO FINISH IT>

[GammaFlat]

Now I'm scared.  I have been working on a 76 750 for years.  I got the bike with loose spokes and eggshaped spoke holes in the rear hub.  I was able to find a set of wheels from a 78 (mags - aha! no more spoke problems).  I remember eye-balling the wheel and initially being a bit puzzled about spacers (this was a couple years ago).  I thought by the time I buttoned everything up, it all looked good but now that I've read the previous post about 78's having re-aligned wheels, I'm scared.  Of course I tossed the old wheels, swing arm as well as many other parts I should have kept if for no other reason than to share with those who need them - darn - didn't know about this forum then.  I'll get out the string, levels, weights, etc. and post my results but if anyone has a notion of whether I'm in trouble or not, I'd appreciate a reply.  If I am in trouble, I'll be looking for wheels  .  ...and I'll also have a set of 78 mag wheels for sale. 

[ProTeal55]

Chippy, glad to hear alteast SOMEONES project is going well...
Post some pics of that beast when all is complete....

[GammaFlat]

Found an article about checking alignment: http://motorcyclistonline.com/howto/string_align_motorcycle_wheels/

I'm afraid I'll need beer after I check mine 

[eurban]

Silcondoc-  Yep in the end I pretty much figured Honda did things OK and that my setup was stock.  For alignment, the string line method worked very well and precisely for me.  Pretty much as Hopalong described it except . . .Since the rear wheel is fatter than the front you will need to insert between the taut strings a spacer (a cut pencil is good) that is exactly the width of the rear tire.  That way when the rear wheel is adjusted to be pointing eactly striaght forward there will be no gap between the string and the wheel on either side but when its off there will be a gap.  No spacer means that you have to be way the hell off before you see any gap.  Also. the centering of the front wheel will be a gradual process where you do the process a few times getting the string to wheel space up front even, adjust the rear to zero gap and the checking the front distances again, tweeaking slightly and readjusting the rear ever so slightly.  Lineing things up with the chain seems very crude because the front sprocket has a good amount of play in it (at least on my 78 which uses a stop to keep sprocket from floating off but does not solidly bolt the sprocket to the drive flange) and this slop should be adequate to allow the chain to lineup  when you have acually adjusted your rear wheel to point at the front wheel which I would think is the ideal for correct handling.  I noticed a couple of things once I got things aligned correctly.  The rear tick marks on my swing are were off by about three of smaller marks which is a bit more than 1/8th of an inch.  My newly installed front forks were twisted  (front wheel straight ahead but handlebars not) requireing some additonal work with string lines and plumb bobs and then a recheck of front to rear alignment.  This process took a good while and was probably more precise than required but it should make for some nice handling improvements one I get those last few bits together and put her on the road again.