The suspension guide in the brief is the USD fork, the shock, and the head and wheel bearings. Those are the pieces that make a bike feel finished or feel dangerous. Spring rates and sag are not in the brief. This page will not supply a millimetre of sag to aim at.

Fork seals

USD forks are what the brief tells you to service. Confirm you actually have them on the bike in the stand. The 2006 generation is “a new fork”, so seal kits from a 2003 bee-tail are not a default fit. Four-stroke forks are undescribed. To verify the seal number against the fork, not against the model name on an auction listing.

A weeping seal shows as a ring of oil on the leg and a dirty dust cap. Ride it to the MOT like that and you will also have oil on the disc. Replace the seal and the dust cap together.

The outline, which you then match to the manual:

1. Support the front so both legs can leave the yokes without the bike falling.
2. Note the position of anything that clamps a leg, with a photo, so the fork goes back at the same height in the yoke.
3. Drain the oil. Keep a note of how much came out. That volume is a clue, not the specification. The specification is To verify.
4. Split the leg by the method in the manual. Some forks are topped out against a damping rod, and a homemade slide hammer is how the threads strip. If the manual wants a special tool, the tool number is To verify. Wait for the tool.
5. Pick the old seal out. Clean the bush. A scored bush needs a new one, not a new seal on top of a groove.
6. Drive the new seal square, with a driver that bears on the metal, not on the sealing lip.
7. Refill with the weight and the level or air gap in the manual. Both are To verify. Set the oil with the spring out and the leg collapsed or extended, exactly as the manual says. Those two methods give different levels.
8. Torque the cap and the yoke clamps. To verify.

Pump the fork before you ride. A leg that stays down is a missed oil level or a bent rod, not a “stiff new seal” to be ridden in.

Shock

Look for a weeping shaft, a soft ride that has no damping left, and bearings in the linkage that knock. Linkage lengths and spring rates are To verify. A shock from another generation may bolt up and still sit the bike at the wrong height. Measure the eye-to-eye length before you swap, and compare it with the manual. Do not compress a spring with a pair of screwdrivers. A proper compressor, or a shop, is the tool.

Headstock

Lift the front so the wheel is free. Turn the bars. A notch in the straight-ahead position is a worn bearing, not a tight one. Strip, clean, and fit the new bearings with grease the manual names. To verify the grease and the torque. Set the bearings so the bars fall gently to one side under their own weight, with no notch, and then follow the manual’s torque rather than “a bit tighter than that”. Overtight bearings notch themselves within a few hundred miles.

The lock stops you checked in guide 1 should still meet the frame stops, not the tank.

Wheel bearings

Spin the wheel and feel for rumble. Rock it at the rim for play. Rear wheel bearings on a bee-tail also live next to a speedo drive that the brief says wears out. On the RSV-style bike the speed signal is a sensor, not that drive. Do not buy a speedo drive for a PY.

Bearing numbers are To verify. The current four-stroke has a wider rear tyre of an unstated size, so its rear wheel is not assumed to share a two-stroke bearing. Press bearings square. Grease is To verify. A dry sealed bearing fitted with the seals popped out “so you can pack it” is no longer the bearing you bought.

Torque the axle and the pinch bolts. To verify. Then spin the wheel again. A new bearing that feels notchy in the hand was pressed on its inner race through the balls. Replace it before it ruins the hub.