So you want to go fast? - Part 1
Ok we have ascertained that the suspension plays a vital role in getting your bike around the corners fast and safe, lets assume your doing a track day on your 916 or 748 and want to get the most from it.

Firstly check the chain adjustment, make sure it is in good condition and has no tight spots, if its too tight the suspension will bind up and probably snap the chain or cause wheel spin exiting the corners. My golden rule of thumb is the rivet of the chain should be level with the lowest part of the swinging arm, you may have to get on your hands and knees to check this and you may feel it is a little slack, but I have never snapped a chain yet, whereas many others have.

Remember the factory spent many hundreds of hours of testing to get the settings to put in your handbook so you should always use them as your default settings.

Lets say your bike has 5000 miles on the clock and the suspension and gearing is still as it left the factory, it is 95% probable that the rear sag and the ride height are now too low. Lift the bike up by the silencers and you should have about 10mm of movement on the rear shock absorber, this is called sag. Adjust the sag by the threaded rings on the top of the shock, the tool provided in the toolkit can only adjust the shock when it is off, so a can of WD40, a large screwdriver and hammer will do the job.

Once the sag has been adjusted you need to check the ride height, ideally you need the special ride height tool, but as a guide, with 10mm of sag, measure from the centre of the rear hub nut up too the top exhaust mounting bolt under the seat, this measurement should be around 585mm. As I said it's only a guide as the subframes may vary slightly. Adjust this by turning the ride height rod, remembering that the threads are left and right handed on the rose jointed ends. Use the compression and rebound damping settings as in your handbook for your specific machine as starting point.

Front suspension is notoriously hard, spring preload can be reduced from the factory 20mm setting to about 40mm, compression damping (top of fork) 7 clicks and rebound damping 5 clicks (bottom of fork). I wouldn't recommend lowering the front of the bike by raising the fork legs through the yokes, but if you do, only go one ring maximum, this may aid turning on a tight twisty circuit.

If you get into a few problems on the circuit here is a few tips that might help you out.

If the rear wheel starts to spin coming out of a corner

  • The rear end is too stiff
  • The chain could be too tight
  • The rear ride height could be too high
  • Too much preload on the rear shock
  • Too much compression damping on rear shock
  • Too much rebound damping on rear shock

If the front end looses grip coming out of the corner

  • The front end is too stiff
  • Increase front fork rebound damping
  • Wind off the spring preload some more
  • Try a harder spring in the rear shock
  • Lower the front ride height (One ring)

If the bike shakes in a straight line

  • Check the steering head bearings
  • Check the wheelbase, It does alter when gearing is changed, fit longer chain
  • Check the engine bolts and swinging arm bolts are correctly torqued up

Also remember a lot of problems are caused by too much rider input, so you need to relax while riding and try to make all your movements as smooth as possible.
 
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