Team Go Dog, Go! Modified Partial Streamliners

[wobblywalrus]

The outriggers attach the frame to the swingarm bushings.  The pictures show one alone and attached to the swingarm.  All bolts attaching the outriggers are also loose for chassis alignment.  They are tightened after the assemblies are in position. 

[wobblywalrus]

These are alignment buttons.  Two stick in the rear axle ends and the other two go in the swingarm spindle ends.  They are different lengths so measurements between them are parallel to the bike centerline.

[wobblywalrus]

The chain adjusters on the rear axle are used to pull the wheel back an equal distance from the swingarm spindle on both sides.  A trammel is used to measure this distance using the dimples in the adjustment button ends.  Now the axle and swingarm spindle are parallel.  Do not use the chain adjustment marks on the swingarm to do this.  They might not be stamped in the correct locations. 

A straight edge is placed against the rear sprocket.  Note how the rear sprocket is about a quarter inch to the right of where it should be.  This offset causes a power loss in the chain drive system and more rapid chain and sprocket wear. 

[wobblywalrus]

This photo shows the offset.  This was with the short swingarm.  The next photo shows the straightedge against the front sprocket with the lengthened swingarm.  The sprockets are in line like they should be.

Throughout the decades I have checked the sprocket alignment on many bikes.  It is more common than not for them to be out of alignment.  It is important to check this and make corrections to minimize drive train power losses.

[tauruck]

Bo, not always easy to get the straight edge into position to measure alignment.

This kid I used to help with his kart was a gear cutter by trade. He had a 14 second lead and tossed the chain. Next heat same thing.
Eventually I asked how he aligned the sprockets?. "OH, I just Eyeballed it". 😂😂😂😂😂. 20mm offset. We won the third heat.

[wobblywalrus]

You would think that a guy who machined gears would be fussy about almost everything...

This is wheel alignment for the typical bike.  It is a friend's Bonneville that handled funny.  It would be hard to drop into corners when going left and it liked to flop into the corners going right.  A typical wheel alignment issue and we fixed it.

The chiropractic table was leveled by putting different thickness wood pieces under each leg.  The front of the bike was tied down in four directions so it would not roll.  The back was left free.   

[wobblywalrus]

The width of the front and back tires are measured.  As a sidenote, the front is a bias ply tire and the rear is a radial.  Triumph sold the bikes with this combination.  Both of my riding buddies like the setup so much that they renew the tires with OEM replacements.

[wobblywalrus]

The alignment jig and spacer plates are taken out of storage.  The spacer plate thickness is as close as possible to:  (back tire width - front tire width) / 2  The same number of spacer plates are used on each side of the front tire.

The sidestand spring hit the top of the jig rail.  The tires needed to be raised.

[wobblywalrus]

This is a block under the tire to hold the bike up for clearance over the rail.  The jig is bolted up around the front wheel.

[wobblywalrus]

A plumb bob is hung down from the center of the frame.  The bolt hole where the horn goes is halfway between the downtube mounts and it is in the center of the frame.  The bob was hung from there.  The wood piece over the jig rails shows a line halfway between the rails.  The four tie downs holding the front of the bike are adjusted so the bob hangs halfway between the rails.  The front wheel is manipulated until it is plumb and the bob is centered.     

[wobblywalrus]

The swingarm spindle is loosened.  The rear axle, too.  The wheel is twisted until it is plumb.  The chain adjusters are used to make all four corners of the rear wheel touch the jig rails.  The swingarm spindle and axle nuts are tightened.  Everything is rechecked to make sure the wheels are plumb, the bob is centered between the frame rails, and the wheels are aligned within the jig.     

[wobblywalrus]

Measurements are made as shown.  These are used when adjusting the chain.  The distances change every time the bike is disassembled and rebuilt, so these measurements are valid until then.

Of course, the steering head, wheel, and swingarm bearings should be in good shape before this is done.  Also, the rims need to be true and the tires need to be correctly seated on the rims with no bulges in the sidewalls.

A series of posts in a few months will show another way to do this.  I miss the days when I did not have time to do something like this on Christmas Eve.

[wobblywalrus]

The chain adjustment distance is always larger on the left.  It was 0.050 inches larger in 2017 and 0.021 inches larger in 2018.  It is different every time the bike is put together.  The attached is made from the setup in Reply 3467 when the axle and swingarm spindle are parallel.  The adjustment distance is 0.030 larger on the left.  What this means is in both 2017 and 2018 the wheels were in alignment but not the sprockets.  The sprockets need to be in line to get the most efficiency from the drive train.

The problem is the alignment of the upper frame, engine, swingarm and axle when everything is bolted together.  This is the method I am working on.  First, loosen all bolts holding the outriggers to the frame and swingarm spindle.  Second, loosen the swingarm spindle and all engine mount bolts.  Third, loosen all bolts holding the upper to lower frame.

Now, the rear axle is adjusted to the 0.030 inch offset as shown on the attached and the axle bolt is tightened.  The chassis is jacked around until the wheels are plumb and in alignment.  Then all bolts are tightened.  The goal is to have everything in alignment when the job is done.  The details of how to do this are being figured out.

Folks tell me that the alignment issues I am dealing with are common to many modern bikes.  The multi piece frames like on the Triumph are more suited to robotic and semi-robotic assembly.  It takes lots of manual labor to install the heavy modern engines in full cradle frames.  Those old one piece style frames did not have this issue.
 

[Old Scrambler]

Merry Christmas, Bo................I use a frame-jig and a laser to get the wheels aligned........then put the laser on the sprockets and machine or space the carrier as needed, along with proper axle spacers. 

[wobblywalrus]

Dennis, can you show us how to use that laser?