My CBR600f 2002 front end doesn't feel good so want to service the forks.
I have never touched forks before so I am a complete novice.
Bike has clocked 36000 + miles and I am sure the fork oil has not been changed once(at least not in the last 20000 miles for sure).
Now my thought is that since the forks are coming out, might as well do a full rebuild-reshimming, respringing etc.
I have few questions which I hope the DIY gurus here can answer-
1)Do I really need to change the springs/valves etc or a proper clean and new fork oil would be enough to 'transform' the bike.
2)Would new springs and valves be worth(gues £200-£300) it? Would I get far better results over just changing oil?
3)Assuming I go for new springs, would a 9.5 rated spring be enough for my 85 kg with gear frame?Or should I go for 10 given I occasionally take a pillion?
4)Which valve shim kit is recommended? I see a few race tech stuff available for £100 but not really sure if they provide for both rebound and compression. Are the valves/shim replacements identical for rebound and compression?
5)I am not too sure if the savings in going the DIY way even worth it(I don't even have a head stock stand) Or should I just go the tuner and drop £500-600, may be more?

Thanks in advance!

 

Changing oil alone won't make much difference. You might notice a little change if you change oil weight.

Springs will make a good change, as will the racetech valves. Your factory springs are too light for your weight and more than likely, worn out. Go 1 step heavier than what it says, as they will settle and get softer as you use them.

Forks are pretty easy. The hardest part is getting them off the bike. There are lots of threads here and tons on YouTube to have a look at. They are pretty much all the same, just know what the fluid level is supposed to be.

Do it right. Get new seals, bushings, fluid, springs, and (if you can afford them) valves. Then after all that, set them up properly.

It will make a world of difference.

 

Thanks for your reply. I think I'd go for Ohlins springs and reuse the stock pistons and valves. There's a k tech piston kit available but £500 seems very steep to me. Gold valves would be at least £100 a pair still so not gonna get them as well.
How Logan no do stock valves last anyway? Would it be okay if I reuse them?
Also what did you mean by 1 step heavier? Did you mean with respect to the stock which I think is 0.66 kg/m or did you mean with respect to the calculated required rate for my weight which is 9.5 so go for 10.5?

 

Go one step heavier than whats recommended for your weight.

The stock valves don't really wear out, they just aren't as good as the upgraded ones.

 

So after dilly-dallying for a long time, I finally got around to do the fork job. the ohlins springs arrived almost 2 months ago as did the allballs bearing kit. I finally stripped the bike last week, lifted the front(pretty ingenious there as well-more about it later) and got the old races etc out. Fitted new races and bearings, stripped the fork , cleaned everything and replaced most stuff-new seals, bushings and or rings, even spacer seat, although I couldn't get the oil lock out -it was stuck- to change the O ring in it. In went the new ohlins and followed the Haynes to the T there. But now after putting everything on(save the plastics) I hear this clicking noise from the front. Now I initially thought the bearings were loaded light and re did the torquing. I checked for any free play in the steering stem and don't seem to find any. In fact even after tightening the adjuster nut so that the steering has considerable drag the noise is still there.
Here is a description of the noise-
It comes when the front comes down after I press down upon the back with the bike on centre stand and release. Doesn't come when I press down but when I release and the wheel comes in contact with the ground.
It also comes when I push down on the forks vigorously with brakes on. It does NOT come when I do this with no brakes. Having spent some time to track the source, I think the clicks are coming from the right fork and not the bearings. I am almost sure, so tomorrow I will slide the forks off and check them individually. I am in no mood to restrip the forks to inspect frankly after toiling so hard to strip them and driving the seals down etc. So would be great if someone can give any hints. The fact that I undid the compression valve to 'clean' it might have to do something with it? I am absolutely sure I put the retaining clip on the cartridge back on though. Or that the right fork was the one I had most struggle to drive down the seals as I was experimenting with different stuff till I got it right finally?
A look at the parts cost for the forks gives me the chill guys. Help!

 

The clicks were coming from the fork. Turns out I was sent the wrong springs.
They sent me the Ohlins for R6! THe CBR takes 08670-95 whereas they sent me 08760-95 which is much shorter. This meant that the initial compression was taken by solely the cartridge and oil and the click was heard when the spacer hit the top bolt.
And this after they sent the wrong one to a wrong address initially and I had to call them after having waited for close to two weeks.
Bunch of loonies.
I didn't ride the bike of course but is there a chance the cartridges are damaged because I compressed the forks several time after installation to check the fitment and later to investigate the source of the clicks?

 

Finally received the correct springs and after some chasers the refund for the return shipment. Can't believe these guys are premier ohlins dealers in the UK. They did offer to have the forks examined and refitted with the correct springs for me but that'd meant sending the almost complete springs by mail and then waiting for God knows how long for them to come back. So decided not to as I had expended so much effort into doing the forks up and there was no guarantee they'd have used new seals etc after stripping the forks again given the shoddy service I received anyway.
End of rant!
I simply tossed the new springs in and man what a difference. They are much stiffer than the oem(went for 9.5 rated springs) and don't dive down too much under heavy braking. Bike is so much more composed in corners. Although the old springs were umm..old plus I had new steering stem bearings installed as well so I was always going to see drastic improvements but hopefully these new ones won't sag too much too soon. Ohlins are supposed to be top notch anyway.
Speaking of steering stem bearings had a tough time dialing the load.
But eventually dialed it in, put the wheel and calipers back on and I was done.
Rechecked all the bolts for proper torque settings just to be safe and out went for a test ride. Bike is riding super now.

Next up is upgrading to SS brake lines and caliper rebuild. I have already received HEL SS lines. Awaiting the caliper seals etc to arrive
Oh and an ohlins race shock has been ordered as well. They are used from ebay but look in fantastic condition and at GBP 550 were half price of a new one so hopefully a steal
Plan is to have the upgraded suspension dialed in at a suspension specialist shop and hopefully do one or two autumn track days before winter misery sets in

Morale of the story- Always check the part with the oem before replacing!