Advice on CBR600F3 rear shock settings

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alexhumber
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Advice on CBR600F3 rear shock settings

Post by alexhumber » Tue Jun 11, 2019 6:32 pm

Hello all,

Does anyone know the factory damping settings for the F3 rear shock (the one with remote reservoir)? And have recommended settings for ~80kg rider fast road riding? It doesn't feel quite right, and I would like a reasonable baseline to start my adjustments from.

I've searched around online and on here with no success. Found a manual but that just mentions spring preload.

Thanks!

Alex

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Re: Advice on CBR600F3 rear shock settings

Post by sa.racing » Wed Jun 12, 2019 11:17 am

There aren't really any tried and tested base line settings available as suspension tuning is all about balance and will change from rider to rider and is largely dependent on the setup in the forks,

for example although they are separate units you want to think about the bike as a whole unit rather than front and rear suspension, its much more important to balance the chassis and get the bike working in balance and then you can fine tune from there.

when tuning or adjusting suspension you want to work at it like this,

Question 1
what does the bike do that you don't like? for example does it dive too much under breaks or bounce around too much on corner entry?

Question 2
what does the bike not do that you want it to do? for example it steers too slowly into corners or the bike doesn't absorb bumps very well

Question 3
Whats your current set up? EG:

Forks are they stock? what sag measurements are you running?
Rear shock, do you know the spring rate or is it a stock F3 spring?

post your answers to questions 1, 2 & 3 and lets see if we can help you

Si

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Re: Advice on CBR600F3 rear shock settings

Post by alexhumber » Sun Jun 16, 2019 6:57 pm

sa.racing wrote:
Wed Jun 12, 2019 11:17 am
There aren't really any tried and tested base line settings available as suspension tuning is all about balance and will change from rider to rider and is largely dependent on the setup in the forks,

for example although they are separate units you want to think about the bike as a whole unit rather than front and rear suspension, its much more important to balance the chassis and get the bike working in balance and then you can fine tune from there.

when tuning or adjusting suspension you want to work at it like this,

Question 1
what does the bike do that you don't like? for example does it dive too much under breaks or bounce around too much on corner entry?

Question 2
what does the bike not do that you want it to do? for example it steers too slowly into corners or the bike doesn't absorb bumps very well

Question 3
Whats your current set up? EG:

Forks are they stock? what sag measurements are you running?
Rear shock, do you know the spring rate or is it a stock F3 spring?

post your answers to questions 1, 2 & 3 and lets see if we can help you

Si
Thanks, I want to get the bike relatively balanced then fine tune from there as you say.

The rear end feels both too soft and to soft at the same time - prob need to up the preload and also relax the damping but what I want to know is the stock settings to work from then go from there as that's what I usually do. It feels like it's all way off. Front end also dives far to much and I've tried various things such as stiffer springs and oil level/weight but not much success really. I can live with the front after all it's a 25 year old bike with very limited front end adjustment and I'm no motogp rider.

Rear shock is a stock F3 spring, as far as I'm aware.

Cheers!

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Re: Advice on CBR600F3 rear shock settings

Post by sa.racing » Wed Jun 19, 2019 10:14 am

Stock spring on an F3 shock is 150 newtons which to me seems a bit on the stiff side for an 80kg rider but I haven't got my notes handy so couldn't say for sure,

Generally the F3 shock conversion works well on the 400's because the shock is very under damped in stock form, when you add a lighter/softer spring for the 400 the softer valving works better with the softer spring and it all just kinda works!

the problem your going to face with the front forks is because of the orifice style damping design they lack any real low speed damping control (low speed = slow damping movements like break dive and not the speed of the bike) and way too much high speed damping (high speed is fast damping movements like potholes and sharp edge bumps) which makes the bike feel mushy and soft and makes the front end dive a lot under breaking and really harsh and unpleasant over sharp bumps and potholes! stiffer fork springs will work wonders (proper linear springs of the correct rate for your weight not those silly progressive shite available on ebay) but my advice would be to seek out some cartridge emulators! if your reasonably good with DIY you can pick them up second hand usually for not a lot of money and install them yourself if you've already got good springs this will make the world of difference for very little money which leads us on to the rear...

if your going to try and set up the rear shock with the front end as it is your going to struggle! you will need to balance the shock to the forks which as we've already established is soft and mushy! if you set the rear to where it feels good with nice firm compression and quick but controlled rebound damping, with the front end being so soft and uncontrolled the rear will tend to pitch you and your weight forward and try and throw you through the screen every time you hit bump!

as I said before there are no factory settings for this shock so to get a good base line to start from take the bike and stand in the centre, support the weight of the bike on your leg and place your hands one on the seat and one on the tank and just gently push down with even pressure and get a feel for each end of the bike, do they compress at the same or similar speed/force? does one feel softer or slower than the other do they rebound at the same rate, does one return faster or slower than the other? as you have no adjust ability in the front its basically a case of trying to match the rear to the front as best you can!

now you can see why I suggested to improve the forks as its a double edge sword, if the forks are under performing then the rear needs to be balanced to it meaning you end up with a below par set up, if you set the rear up well the bike will be way out of balance, just my 2 cents worth ;)

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Re: Advice on CBR600F3 rear shock settings

Post by alexhumber » Mon Jun 24, 2019 8:22 pm

Thanks for info! All very useful. I'll see what I can do.


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