Rear wheel centered in frame?

All this calculation of offsets gives me a headache. Suggest you set up a construction laser at the front of the bike. It makes the assumption that the front wheel is dead centre of the forks. The plane of laser light will give you vertical and horizontal location. It will require re lacing the rear wheel to meet the vertical plane of the laser. The rear wheel will be centered to the frame and inline with the front wheel and the bike will go down the road - straight.

The frame is symmetrical
The engine/gearbox cradle is offset 1/8" to the left. The swinging arm is offset 1/8" to the right so the axle pads end up centred in the frame

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That's the problem and I made a similar statement as if it were fact :? I have seen that comment before but I have never seen and measured a cradle or front mount that wasn't at least .25" offset and I have not seen a 750 swingarm that was offset in the opposite direction. On my bike the front and rear offsets are 0.31" and 0.25" respectively so you can imagine what that does to handling and anyone who says rear alignment doesn't matter has never gone over 45mph Shimming mine to match rear stopped it pulling left.
Maybe the 850's do have an assymetric swingarm and only having seen two non Mk3 I can't really comment but they were symmetrical as near as......

Keith1069 said:

I have seen that comment before but I have never seen and measured a cradle or front mount that wasn't at least .25" offset and I have not seen a 750 swingarm that was offset in the opposite direction On my bike the front and rear offsets are 0.31" and 0.25" respectively so you can imagine what that does to handling and anyone who says rear alignment doesn't matter has never gone over 45mph Shimming mine to match rear stopped it pulling left.
.

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I just did a rough check of my MkIII, and measured a difference in gap between the frame tube and cradle at each side of just over 1/4" at both front and rear of the cradle. The offset being half the difference - so approximately 1/8 - 3/16" offset.

Keith1069 said:

Maybe the 850's do have an assymetric swingarm and only having seen two non Mk3 I can't really comment but they were symmetrical as near as......

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I hope we can agree that the frame is symmetrical? If the swinging arm is also symmetrical and the cradle is offset, then that would cause both shocks to lean to the right by the amount of offset, or, the cradle-swinging arm assembly is intended to be out of parallel with the frame in order for the swinging arm axle pads (and thus the lower shock mounts) to be in a position to keep the shocks upright.

When this topic was discussed a while ago, I know I measured up a spare MkIII swinging arm and it did appear to be built offset to right at the plates by approximately 3/16".

When this topic was discussed a while ago, I know I measured up a spare MkIII swinging arm and it did appear to be built offset to right at the plates by approximately 3/16".

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and I remember you doing that, now you mention it.

L.A.B. said:

You seem to have the R/H lower shock mounting on the wrong side of the swingarm axle pad?

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+ with LAB !!! :shock: Correctly mount the shocks and then take another look, wheel offset wrong or frame/ cradle bent may still be the issue, but install shocks properly for a baseline.

DogT said:

You need to make sure the drive sprocket lines up with the rear sprocket first.

Dave
69S

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sprocket-wear-t13286.html#p157072

+1 You can't use the adjusters to make changes in wheel alignment. See the thread on sprocket wear.

It's a matter of faith that if the sprockets are set up aligned and the engine/cradle/swingarm is square, then the rear wheel will ultimately be situated lined up along the backbone pointed at the headstock.

As Keith found out about manufacturing tolerances though, 'many are the slips between the cup and the lips'.

There is a pretty good youtube video on wheel alignment using the string method. The guy even speaks correct English. I hope I can post the link so here goes: http://www.youtube.com/watch?v=RBxK-OQ--fg



Tim_S

Mine has always been to the left a bit. Wheel, frame loop, and fender never line up. Yours looks much worse.

There is a difference between alignment, and position. Wheel a bit to the left can still be in alignment, mine is. This bad, better get a serious look see at the basic frame.

All 3 750's in Madison Co. Arkansas had their rear tire centered ~3/16" to 3/8" to the Left of center so a bother to try to center fender on tire and rear loop. Hubs drum or disc are a non issue d/t fixed spacers assembly, so as stated, just spoke adj rim to leave them as close to midline spine-stem as possible. There can be a combination of factors that leave a proper spoked rear off to one side. The World's Straightest Commando in The Phantom Oiler site has tedious extensive list of these factors found in one particular example. If a Cdo has been run a while with conflicts in chain alignment tension as well as road tire vector tension, I'd be pensive of the increased half life chances of radiative fission of half dumb axle stress riser. Check the sprocket teeth sides for sense of this issue.

hobot said:

All 3 750's in Madison Co. Arkansas had their rear tire centered ~3/16" to 3/8" to the Left of center so a bother to try to center fender on tire and rear loop. Hubs drum or disc are a non issue d/t fixed spacers assembly, so as stated, just spoke adj rim to leave them as close to midline spine-stem as possible. There can be a combination of factors that leave a proper spoked rear off to one side. The World's Straightest Commando in The Phantom Oiler site has tedious extensive list of these factors found in one particular example. If a Cdo has been run a while with conflicts in chain alignment tension as well as road tire vector tension, I'd be pensive of the increased half life chances of radiative fission of half dumb axle stress riser. Check the sprocket teeth sides for sense of this issue.

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I finally decided beyond a shadow of doubt that this wheel had been strung wrong... probably offset had been put on speedo side instead of brake drum side. Yesterday I threw the bike on a trailer and hauled it over to the independent Harley shop that had built the wheels. The guy who did the work went on about a 5 minute rant about never again working on anything that "ain't outa Wisconsin", but he must have realized that he'd f'ed up because he finally agreed to restring the wheel, adding "I hope you're not in a hurry because I'm swamped right now". I'm sure he doesn't have the factory specs on what the offset is, so I guess he just plans on measuring how much the wheel is off and restringing it to get it as close as he can to the center of the swing arm. According to your post Hobit, it sounds like this will suffice. I'm glad he's making things right on this but I can only guess how many months it will be before I see the bike again. He says he's swamped now so since he won't be getting paid this time around, he'll probably wait till he's got some slow time in between jobs to do the work... which being a Harley shop, I imagine he doesn't get a lot of that. So, good news that he's making things right, bad news, my Commando project just went into a state of limbo of undetermined length.

I'll tell you, I've brought my bikes to Harley shops on 3 different occasions over the years. Each time, they looked down their nose at me because I didn't own one of their preferred over priced pieces of shit, and each time they either f'ed something up and spun up a bullshit story to support it, or outright screwed me. One thing for certain, that Harley wheel builder guy doesn't have to worry about doing any more"non Wisconsin" work as far as I'm concerned, as in the future if I ever get desperate enough to consider bringing one of my bikes to a Harley shop, I will give myself a slap, then go out and chop the bike to pieces and sell them on ebay.

If you ever have the need, I have access to an old guy that knows how to properly lace and true a norton wheel. He is in Milwaukee. And does it for $1 a spoke. My front disk wheels were perfect every time. He works on Harleys but appreciates real bikes.

bwolfie said:

If you ever have the need, I have access to an old guy that knows how to properly lace and true a norton wheel. He is in Milwaukee. And does it for $1 a spoke. My front disk wheels were perfect every time. He works on Harleys but appreciates real bikes.

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Thanks, that's good to know. I wish I knew about him back in May. It would have been worth the hour and a half drive to Milwaukee.

It's really not that hard to do it yourself. I'd just loosen it all up and start tightening one side to get it close and then start on the other side. It's not magic. You really should have measured the offset in relation to the hub to start with and given him the measurements. I doubt if many people know what it's supposed to be unless they work on Norton rims. I think it took me 3 or 4 hours to respoke my 2 rims.

Dave
69S

Appreciate the honorable mention Robbit and what you endured and now wait on for mainly cosmetic hassles. Wes and I have yet to having anyone point out the sloppy factory assembly of our non-American iron and for sure can't tell while riding. All's I can say is I've now got a bit better self impression after learning to spoke Norton wheels, but it took me about a season for each end and wished I'd had an obnoxious shop doing it instead of me each new step of the way. Hub position is set by factory spacers so just spoke tweaking a bit to center rim to stem and stern. I am glad you are seeking a more perfect Commando as they will out last us,though the next owner will likely not notice what the past generation went through. I've posted about putting a 16" rear on my Peel special, got another Water Buffalo hub but not at all looking forward to the tedium and time to steal. So don't think less of ya farming the job out while rest of life attended to before riding into the wind on flaming streaks into the sunset.

DogT said:

It's really not that hard to do it yourself. I'd just loosen it all up and start tightening one side to get it close and then start on the other side. It's not magic. You really should have measured the offset in relation to the hub to start with and given him the measurements. I doubt if many people know what it's supposed to be unless they work on Norton rims. I think it took me 3 or 4 hours to respoke my 2 rims.

Dave
69S

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I didn't want him to be able to fk it up and then come back to me with "well YOU gave me the offset", so I brought the wheel in to him and had him measure it himself. I still think he got the offset right... just put it on the wrong side. I considered doing it myself. In hindsight, I wish I had at least attempted it. Could have set up a jig and taken it slowly... but it's out of my hands now. All I can do is wait and hope he doesn't take the rest of the summer to do the work.

Well, here's the latest. I got the bike back from the guy who built the wheels. He said he moved the offset over so the wheel was positioned in the middle of the swing arm. Actually, it favors the right side by about an eighth of an inch now. My main concern though is the "cant" of the wheel. I set a level horizontal across the frame and shimmed the center stand till the bike sat level. Then I checked to see if the vertical axis of the wheel was plumb with the frame. The pictures show that the wheel is out by about 3/32 to the left over a distance of 2 feet. I can't figure out what would cause this or how it would be adjusted?

The wheel spins true by the way.

Swing arm or cradle is bent. Talk to Guido.

But I wouldn't trust anything to be true after 40 years, even the rear loop. It may not matter.

Will be undetectable in useage but may be from iso cushion sag or even a tweated swing arm or shock spring balance.

Is that a Snuggie sitting in that oil pan next to the bike?
You are also lying the level up against the tire.
3/32"? I have a laser level to check it. It may just be out by 3/64 ths

Guido said:

Is that a Snuggie sitting in that oil pan next to the bike?
You are also lying the level up against the tire.
3/32"? I have a laser level to check it. It may just be out by 3/64 ths

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The level that's up against the wheel I'm just using for a straight edge. The metal ruler against it is actually a 2' carpenters square, and it's sitting on top of another level that I shimmed up to sit level on the ground, giving me something to go off of.

3/64ths I can live with... if it's enough for my eye to catch it starts bothering me.