Adjusting the preload (sag) on my Honda CBR250R

By | October 18, 2013

On my CBR250R the suspension is quite soft stock as most will find who own the bike, one way to help with this is adjusting the preload on the suspension. The rear shock absorber does have an option to adjust it via a c-spanner and can go from 1 (soft) to 6 (hard). Mine is set at 4 and gives me 30mm sag however the front was closer to 60mm stock.

Not having adjustable suspension in the front, you can go out and purchase aftermarket springs / emulators e.t.c. however there is another way to adjust the preload on the front suspension, to do it all properly you will still need to get heavier rated springs for your weight, however I don’t remember ever bottoming out mine with the stock springs, so the spacers should be okay without coil binding the front springs in the meantime. Later on down the track I may get some RaceTech 0.85kg/mm springs. Most people use PVC water pipe to make the spacer longer in the front, however my mate and I went to our local Bunnings store (home hardware kind of store), and found some steel chair legs which were perfect.

If you use PVC pipe you want thick walled 28mm piping, however these chair legs were perfect in diameter and length. So, what I needed to do was add an extra 30mm spacer, the stock spacer in the CBR250R is 100mm. The chair legs I bought were 130mm, perfect.

The legs had a base tac-welded on, so what we did was grind the tac-welds off and then smoothed the ends off with some fine sandpaper. Cleaned the piping with some degreaser and it was done. Then to change the spacers we lifted the bike up from the triple clamp by using a ratchet strap attached to the roof to get the front wheel off of the ground.

Then, one fork at a time, we removed the caps, and then swapped out the spacers and did it back up. What an improvement it made, the bike feels a lot more sturdier and straight in corners and doesn’t dip nearly as much under braking. The pieces only cost around $6 each and were made of steel, not PVC so it is a bit more reassuring for me. Anyone that hasn’t adjusted the sag and preload on their CBR250R I would highly recommend it. There’s a world of difference between having it stock and adjusted properly.