Yamaha Niken Front End Alignment - adjusting toe in

[maximNikenGT]

Am posting this with permission from the original author/owner from the Facebook Niken forums where the owner was encountering a strange left tire suspension "stuttering" only when making deep right-hand turns. 

link to wheel stuttering video:

 

Niken in question was a used 2018, with 36,000 km / 22,370 miles. No accidents / no obvious damage. Owner had already tried to troubleshoot the stuttering of the left wheel by swapping out with new front tires and balancing the wheels. Still experienced the stutter eroding the riding confidence of what is normally a very sure-footed machine. 

After getting suggestions of balancing the front wheels including the hub, whether there was a problem with the rear wheel, fork compression/rebound settings, front suspension blockage, brake calipers sticking, steering stem bearings getting loose/worn,  and even suggestions to perform brake fluid change, turns out the root cause was an out of alignment front end.

From the owner...

"Because the left wheel wasn't aligned with the right both tires were always "dragging" and struggling with each other. When turning right, while accelerating, the front left wheel was the most unloaded and started "jumping"." 

Owner ended up creating his own alignment tool and provided pictures. This was the first time I had ever heard of an owner creating their own alignment tool and wanted to capture it for posterity because of the low production runs of the Niken (at least in the USA), not too many shops will probably even have this tool available.

The original Yamaha tool is called a Wheel Alignment Toe Gage part number 980890-01595 YM-01595. 

According to different owner's post from 2021 (where his new Niken actually came with this alignment tool from the dealership), retail price for the Yamaha tool at that time was $540.99 USD / ~491 Euro / ~417 pound sterling. 

Special shout out to owner Boris Nodelman for sharing detailed information on how he built his own alignment tool for about $15 USD. Specific questions I had about the tool construction included details such as:

• Dimensions:
  • Tool made from aluminum square rail 25x25mm, 60 cm in length. NOTE: Aluminum rails MUST be the exact same size, and the center hole must be the exact center of the rail. 
  • Rail Center holes = 10 mm
  • Angle bracket holes = 5mm. 
• Materials and tools used:
  • 2 Aluminum square rails:  25x25mm, 60 cm in length
  • 2 M10 thread machine screws, 40 cm long that fit perfectly into the fork guard bushing. 
  • 2 M10 nuts
  • 4 spring washers sized for the M5 screws
  • 4 furniture angle brackets: ~75mm x ~62mm  - The furniture angle brackets used on the rails have long holes so they can move about 4-5 cm each. This makes it easy to correctly align them to the wheel rims. 
  • Powered Hand Drill
  • 5mm and 10mm Drill bits that can drill into aluminum
  • Pencil/marker to mark where the holes need to be
  • Hammer and tap to mark hole locations
  • tape measure
  • (suggested) Table mounted clamp to secure the aluminum square rail when drilling required holes. Can be done by hand if no access to clamp. 
  • how the precise holes for toe in pointers and the wheel brackets were drilled e.g. hand drill, pneumatic drill (DO NOT USE), drill press (If you have access to one is great). 

General Build Instructions:

1. Check that the aluminum rails are true/straight with a level or right-angle square. If the rails are not true/straight to begin with, discard and find ones that are true/straight to begin the tool build otherwise it will never give you a true reading when trying to adjust the front end. Save yourself the headache and find aluminum rails that are true/straight to begin with. If  starting with a single long aluminum rail at least 120cm in length, cut rail into two equal pieces of 60cm in length. 

For each aluminum rail: 

2. Find the midpoint of the aluminum square rails and drill a 10mm hole into both rails using powered hand drill or drill press (if available). This will be where the machine screws used to verify toe-in will be mounted. 

2.1 Use M10 thread, 40cm screw and insert into the midpoint holes drilled per the step above. 

2.2 Secure the 40cm screw with a nut on the opposing side to where the furniture angle brackets will be mounted. 

3.1 Drill two 5mm holes to mount the furniture angle brackets at a distance of 17cm away from the midpoint holes you drilled for the toe in machine screws. 

3.2 Using a M5 screw, secure the furniture angle brackets to the aluminum square rails with a spring washer and M5 nut (2x per rail for a total of 4 times). CAUTION: M5 screw tightening should be done with a tool, but not overtightened (you physically can't tighten M5 nut by hand - it's too small). Take care not to scratch your wheels with the furniture brackets.

Wheel Alignment Toe-In Gage Instructions for use: 

Follow the instruction in the Yamaha Niken service manual per below and add spacers as needed. 

* The assembly of aluminum alignment toe in gage rails on  Niken  should be done in the next order:
1. Insert the M10 screw through the wheel axis.
2. Fit the rail over the M10 screw already positioned within the wheel axis. 
3. Adjust furniture angle brackets against rims enough for friction to hold them in place against the inner wheel. 
4. Tighten 2 M10 nuts by hand, from opposite sides, until the aligning tool is in place and the furniture angles lightly pressed against rims (aligning horizontally can be done by building level tool). 

From the service manual.

How to use the toe-in alignment gage and specifications on adjusting shims of varying thicknesses. 

Where to install the adjusting shims. 

Construction of the aluminum rails and hole positioning dimensions. 

After utilizing the toe-in tool, turns out that the front end needed 1mm spacer on the right side adjusting shims and 2mm spacers on the left side adjusting shims. 

After the alignment was performed, the bike no longer had the left wheel "stuttering".