Sproket alignment, Frame problem?

[Gmorrone1214]

Hey everyone, Im kinda confused as to what the problem could be. I almost completed with my build and am trying to align the rear sproket with the front but am having problems.

View attachment 58127
View attachment 58128

This is the original mag wheel with the chain adjusters placed in the same distance with each other. As you can tell the rear is off from the front, and I cannot move the rim any more to the right, this is the rim maxed to the right side and is still off, but lines up in the middle of the frame.


View attachment 58129
View attachment 58130

This is the harley rear rim 1982 sporster, all the way to the right as far as I can, and I also got the rear brake arm shaved down for more adjustment to the right, but it still will not line up with the front.

Would this mean my frame is welded on crooked? When I placed the motor back in everything lined up perfect , and It doesnt look like it is crooked on the bike.

Pic of the bike for you guys

 

[I am Carbon]

I looks a bit off but not as far off as the laser is showing from the 4th pic the laser is not straight down the middle of rear sprocket.
You might use a string along the side the sprockets to see just how much it is off.
You might have to find or get an offset front sprocket

 

[Max Midnight]

Not very accurate I know but putting a rule against both sides of the rear sprocket seems to show similar gaps on both sides of the front sprocket.

As Mr Carbon suggests, if is is out it ain't by much.

The check I would do is to plumb the centre line of the frame then then drop the plumb line from the outer faces of both sprockets and take measurements to the centre line.
I would have thought that any discrepancy could be dealt with by moving the rear wheel over by adjusting the spacers.
Whist this may move the tyre off from the centre line a tad provided the wheel are parallel then this wouldn't matter. Many shaft driven bikes have the rear offset from the front.
If it does bother you then you have the option of increasing the offset of the rim relative to the hub.

 

[fredintoon]

Hi Gmorrone,
What size rear tire are you using?
If it's fatter than a 130 width the chain will rub on it unless you either use an offset transmission sprocket to move the chain outwards or set up the rear wheel with the tire offset to the right.
And yeah, Beemers run dog-tracked and that's not the only weird Germanic thing they got, neither.

 

[Gmorrone1214]

its only a standard 130 rear tire. The last picture uploaded is the stock mag on the rear, and it seems that wont even line up with max adjustment, which is why im confused. It should be lining up with the front sproket without having the get an offset front sproket.

As for the rear harley rim I could try and take more material off the caliper to make it move more to the right, but it looks like it really needs a lot.

What is plumb line?

 

[I am Carbon]

A plumb line is a string with a weight on it.
used for finding the depth of water or determining the vertical on an upright surface.
plumb bob/plumb line

 

[Max Midnight]

What is plumb line?

Plumb line or Plumb bob

 

[fredintoon]

its only a standard 130 rear tire. The last picture uploaded is the stock mag on the rear, and it seems that wont even line up with max adjustment, which is why I'm confused. It should be lining up with the front sprocket without having the get an offset front sprocket.

Hi Gmorrone,
yeah, that's the stock rear wheel set-up and the sprockets would line up no problem on a stock frame.
You are right.
The hardtail has to be warped out of shape.

 

[Gmorrone1214]

Bringing back the dead thread, but I havent been able to work on the project over the winter I dont have a garage.

But I have been trying to figure this problem out. I did the string method with the plumb bob and got the center of the frame on the rear axle. When I center the rim over this mark the sprockets are off by a lot like 1/4 or more. I will be testing it more tomorrow started to get cold outside.

Meaning that the frame is warped? If so what should I do at this point? Guessing give it to a professional to fix the frame.

Would it be better to cut it off and put a new hardtail on or fix the current problem. I mean all the motor mounts are lined up its just has to be the rear section.

 

[fredintoon]

Hi Gmorrone,
before I got medieval on the frame I'd see if the wheel can be set up so the tire clears the frame, the sprockets line up reasonably well and the brake works OK then I'd give the bike a road test to see how it handled.

 

[Gmorrone1214]

Hi Gmorrone,
before I got medieval on the frame I'd see if the wheel can be set up so the tire clears the frame, the sprockets line up reasonably well and the brake works OK then I'd give the bike a road test to see how it handled.

So I went out and got a self leveling laser lever and got the rear sprocket matched up with the front sprocket. The wheel is basically level with the backbone of the frame also.

Put the chain on and tensioners adjusted equally, but I have one concern. The chain kinda sounds like its jumping a little? If that is what it is.

Turn the sound up and let me know what you think.

 

[fredintoon]

Congrats Gmorrone,
you've gotten the world's first completely silent XS650.
That or your sound's fried. Certainly I can hear the engine running on the next clip.
OK, sarcasm now turned off.
The chain certainly looks like it's jumping a little.
Try blocking the bike's rear wheel off the ground and turning it slowly by hand to discover if you can see what's going on.

 

[Gmorrone1214]

Yeah Fred how I had it in the video on blocks spinning the rear wheel. Maybe the adjusters are off slightly. I guess I will 2x check everything again and see how it is.

Also Idk if you would have any ideas but I am not sure how I want to mount the brake caliper.

You can see the gap inbetween the frame and the caliper itself , should I just use a brake stay bar http://www.tcbroschoppers.com/custom-rear-drum-brake-anchor-rod.html. Would this work with that much gap?

Also ideally I wanted to mount it inbetween the upper and lower frame mounts.

I was thinking of welding a threaded bung on the bottom rail and bolting it to that. My concern is when I have to adjust the chain I will not be able to bolt it back up, so I am at a loss on what to do.

I cant fab anything to the caliper itself since it is aluminum and I cannot weld that.

 

[fredintoon]

Hi Gmorrone,
What you got right there will work. Shove a slug of (say) 1-1/4" diameter aluminum barstock between the caliper and the existing frame lug.
Use a (say) 1/2" diameter bolt through the lot, drill the aluminum slug, the frame lug & slot the caliper lug up and down (to allow for chain adjustment) to suit the bolt and put a Nylok nut on the bolt.
That elegant torque stay won't work for you because those things are meant to be used in tension and to work that way your caliper would have to be mounted upside down from where it's shown and that would make the caliper lug point backwards.

 

[Gmorrone1214]

Hi Gmorrone,
What you got right there will work. Shove a slug of (say) 1-1/4" diameter aluminum barstock between the caliper and the existing frame lug.
Use a (say) 1/2" diameter bolt through the lot, drill the aluminum slug, the frame lug & slot the caliper lug up and down (to allow for chain adjustment) to suit the bolt and put a Nylok nut on the bolt.
That elegant torque stay won't work for you because those things are meant to be used in tension and to work that way your caliper would have to be mounted upside down from where it's shown and that would make the caliper lug point backwards.

Okay thanks Fred, I just ordered the Aluminum slug, should get here saturday.
Ill keep send up some pic's once I get it all finished up.
Thanks for the help.

 

[Max Midnight]

That elegant torque stay won't work for you because those things are meant to be used in tension and to work that way your caliper would have to be mounted upside down from where it's shown and that would make the caliper lug point backwards.

As the majority of production bikes seem to have the calliper mounted above the axle their stay would be in compression.
Just curious to know why the TC Bros item would not be suitable (albeit perhaps too long?)

 

[fredintoon]

Hi Max,
arr,matey.
Long and thin goes too far in, short and thick does the trick.
While that particular TC Bros item looks just right for a drum brake's tension stay I wouldn't fancy using it in compression.

 

[Max Midnight]

As I said in my previous post, it would seen that the TC Bros stay would be too long for the intended application but still don't understand why you say it isn't suitable for use in compression. I also understand that shorter tends to be stiffer than longer for the same diameter.
I could understand the comment if the centre section was (say) made from Kevlar where the compressive strength is 1/10 of tensile strength but as aluminium and steel are isotropic materials (i.e. their mechanical properties are identical in all directions) it wouldn't matter which direction the force through them is applied.
Sorry to be a pedant but I would like to know if I am missing the point.

 

[member3480]

I have done a lot of Harley wheels on the back of TC BROTHERS rears and even with the universal kit and the proper way to get it correct is to expand the rear frame to 9 1/2 to 10" and use the proper spacers to get the wheel in line. Your next problem is going to be the brake caliber not running center. The stock TCB hardtail is around 8 1/2" plate to plate and depends on year of wheel it can be 3.75 hub to 4.5 hub. Both of these are 4.0 and frame had to come out to 10" for proper alignment.

 

[TwoManyXS1Bs]

As I said in my previous post, it would seen that the TC Bros stay would be too long for the intended application but still don't understand why you say it isn't suitable for use in compression. I also understand that shorter tends to be stiffer than longer for the same diameter.
I could understand the comment if the centre section was (say) made from Kevlar where the compressive strength is 1/10 of tensile strength but as aluminium and steel are isotropic materials (i.e. their mechanical properties are identical in all directions) it wouldn't matter which direction the force through them is applied.
Sorry to be a pedant but I would like to know if I am missing the point.

This is one where numbers would need to be conjured to determine the loadings.

"Normal compressive load distribution can be used when length/diameter ratios are below 6. Special column loading considerations and limits must be employed when the length/diameter ratios are 6 to 60, and especially at 60-120 (severe buckling phenomena)."