[Konic]

Recently purchased a used 2015 Honda CB500F with ABS and wanted to try and tweak the rear shock pre-load settings to see if I could improve ride comfort but also to see if i could feel a difference in the way the bike rides.


I've studied the user manual, went to the bike and had a good look around the rear shock on both sides to try and find the factory default pre-load setting of 3 - which is supposed to be marked with a small dot or notch i believe. I could not find it at first inspection. I cleaned around the bottom of the shock with alittle brake cleaner and used a flashlight to help, again could not find anything. I tried to feel for the dot or notch with my fingers but again no luck.


Has anyone else faced this issue and if so how did they work around it? As i mentioned i want to try different pre-load settings and choose the one i like, however what concerns me is with no reference point for default setting 3, I dont know what the bike is currently set to, so i'm hesitant to adjust it but would like the option to explore the settings.


I weigh around 65kg or so and if i had to take a guess from my very limited experience and knowledge of motorbike suspension, I would guess the bike is probably set to more of a "soft" pre-load setting but i cannot say for sure.



Do I run the risk of jumping from setting 1 straight to 9 or from 9 to 1 and damagaing the shock (as mentioned in the user manual) or is it not posible to adjust straight from setting 1 to 9 or vice versa?

 

[wollerms]

You need to set your rear sag, see link under rear preload. . Still confused ride over to local Honda dealer and see if they can show you how to adjust the rear shock on your bike. It would only take a few minutes for someone to show you.

Motorcycle Suspension Setup

 

[Oyabun]

So I pulled out a brand new shock from a CBR500, and my trusty motorcycle shock spring compressors, and made a few measurements and observations.
The mark on the shock is a thin painted dot on both sides of the ring - so no wonder if after a few miles - and your prudent cleaning with the brake cleaner - itannot be seen.
The whole adjustment is a half turn on the crown or ring, indeed it has 9 settings (i'll call them 0+8), and it has the clear issue of being able to jump back to zero after the highest preload.
Given that the spring force is close to 90N/mm, and the total adjustment range of preload is ~6.4mm, it will slam down with roughly 580N, or about 59kg of force in an instant going from 8 to zero.
However, by design one cannnot jump from 0 to the 8th setting. So my advise is to adjust the shock to zero (by turning the crown to the right) until you cannot move it any further. Mark this position as this will be your base of counting.
If you want to experiment, try to ride on this setting for some time to get a feel of it.

Once you've read the linked material how to set motorcycle sag or you want to try to add some preload turn the crown to the left (you should feel definite steps as you turn the crown to the left) until you reach the setting you're looking for. I suggest to note it down where you are so next time you don't have to go back to zero to find where your actual position.

While I was there, I've done a few measurements.
Total weight of the shock is 2985gr.
Free length of the shock is 310mm, theoretical maximum stroke is 66mm - but the poly bush starts to engage after 40mm of travel, therefore 56mm of total travel seems to be more realistic.
By feel the shock has absolutely none or minimal compression damping and no gas preload.
Total preload adjustment range is 6.4mm in 8 steps (0+8 positions) or 0.8mm each.
Calculated spring rate is about 90N/mm (11.4mm wire diameter, 6 active coils, 80mm spring OD, what is tapering on both ends), so each preload step adds about 72N or 7.3kg of preload.

Hope this helps ;-)

 

[Konic]

Thank you so much Oyabun, your reply was very helpful and exactly the type of informtion I was looking for! I feel confident about adjusting the rear shock to setting 0 and working my way from there now.

 

[blackburn]

thanks Oyabun!

for 2019 I noticed the rear shock is installed upside down...