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Author Topic: Setting front suspension on an '07 CBR 600RR  (Read 11492 times)

Jim Moore

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Setting front suspension on an '07 CBR 600RR
« on: July 14, 2007, 09:50:38 AM »
I have been reading about suspensions lately and I cam across this on the internet:

Wrap cable ties around the smooth part (stanchion) of front forks near the rubber seal to the forks. Ensure that it does not scratch the stanchion and it is not too tight as to damage the rubber seals.
With the cable ties in place ride your bike as normal using as many riding conditions (corners, braking, accelerating, wheelies and stopples) that you are likely to meet. Then increase or decrease your preload until the cable tie stops about 10 mm before “bottoming out”.
Reducing preload should give you more travel. If the forks bottoms out, reset the cable ties and increase preload until the cable tie stops around 10mm above the limit. You should always leave about 10mm travel for emergencies like slamming into uncharted potholes.


Does that sound like a legit way to set the front preload? I played around with this technique this morning. Even with the preload on full soft, most I could compress the front end with maximum braking (and even one below average stoppie) left about 20 mm of travel. It kinda makes me wonder if I am not understanding something, or if the information on the website is not entirely accurate.
Thanks,

Jim Moore

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Re: Setting front suspension on an '07 CBR 600RR
« Reply #1 on: July 14, 2007, 09:51:30 AM »

Ozjack

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Re: Setting front suspension on an '07 CBR 600RR
« Reply #2 on: July 15, 2007, 02:42:55 AM »
That`s a dodgy technique and leaves a lot of information out of the set-up.

Do the front preload just as the rear is explained, that way if the rider sag and static sag are not within range you know new springs are needed/wanted. The cable tie just gives a place to measure sag from. Obviously... :thumb:

Jason748

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Re: Setting front suspension on an '07 CBR 600RR
« Reply #3 on: July 15, 2007, 10:18:32 PM »
I agree... That's not the way I would ever set-up a bike.

Give me a couple days and I'll write up how I base-line set-up my suspension.
CCS/CRA #92
07 CBR600RR - RACE
Sponsors: Two Brothers Honda, Lithium Motorsports, SpyderLeatherworks

"A lot of people go through life doing things badly. Racing’s important to men who do it well. When you’re racing, it... it’s life. Anything that happens before or after... is just waiting."  -S

bobhope

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Re: Setting front suspension on an '07 CBR 600RR
« Reply #4 on: July 16, 2007, 10:22:43 AM »
nice, cant wait to read it jason  :thumb:
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Jim Moore

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Re: Setting front suspension on an '07 CBR 600RR
« Reply #5 on: July 16, 2007, 12:08:05 PM »
Give me a couple days and I'll write up how I base-line set-up my suspension.

That would be awesome.  Thanks.

Jason748

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Re: Setting front suspension on an '07 CBR 600RR
« Reply #6 on: July 16, 2007, 11:24:34 PM »
OK... Here goes.  This is how I "base-line" my front sag (preload) setting, this may not be where I end up after adjustments, tweaks and Ed's advice (trackside engineering), but this is where I start off.  I am describing this based on using USD forks (05 - current), but it the same process on RWU forks (03-04) you just take the measurement in a different place.  It's really, really handy to have two friends to help you, one hold your bike one to take measurements (have him take ALL the measurements for consistency).

WARNING:  THERE WILL BE MATH INVOLVED, but no test  8)

Forks:
1 ) Place a small zip-tie on one of your fork tubes, this is what you'll be using to take measurements from.
2 ) Get the front end up in the air so the wheel is OFF the ground and the forks are completely extended. (any "under the tree" or "steering stem" front stand is what you should be using)
3 ) Slide the zip-tie all the way up against the seal and take a measurement from the bottom of the zip-tie to the top of the fork bottom.  We'll call this measurement FL1 - Write it down.
4 ) Take the bike off the front stand (and off the back stand too for most accurate measurements).
5 ) With full gear on, sit on the bike in your normal riding position, this is where you want to have a friend to hold the bike up.  Firmly push down on the bars to compress the suspension a bit, then gently let it come back up and settle (all while your still in your ridding position).  Without compressing or decompress in the fork, slide the zip-tie against the seal.
6 ) Take a measurement from the bottom of the zip-tie to the top of the fork bottom.  We'll call this measurement FL2 - Write it down.
7 ) While still sitting on the bike in your normal riding position, with your friend still holding the bike up.  Firmly pull up on the bars to decompress the suspension a bit, then gently let it come back down and settle (all while your still in your ridding position).  Without compressing or decompress in the fork, slide the zip-tie against the seal.
8 ) Take a measurement from the bottom of the zip-tie to the top of the fork bottom.  We'll call this measurement FL3 - Write it down.

Now you have three measurements FL1, FL2 and FL3 and your probably asking yourself:  Well :-X do I do with these now?  I'll tell you:
You plug in the numbers you've written down into this formula:  FL1 - ((FL2 + FL3)/2)  and presto you have your rider sag distance.

So, to plug in some real numbers in for example:
IF:
FL1 = 139mm
FL2 = 110mm
FL3 = 116mm
Then the formula should read:  139 - ((110+116)/2)
First do the addition and you get: 139 - (226/2)
Then the division and you get: 139 - 113
Now have your sag measurement:  26mm

Now depending on what you are doing, you'll need to adjust your preload adjusters and re-measure (FL2 & FL3 only, as FL1 will not change) to get within a "specified range".  I'd recommend shooting for the following numbers to start with (remember these are just starting out numbers).  Depending on your riding style, and comfort range, you may need to go with more or less sag.
Now the the 2005 - 2007 has 120mm of front suspension travel, so:

Street: 34mm - 38mm (approximately 30% of travel used)
Aggressive street / track day: 30mm - 35mm (approximately 27% of travel used)
Race: 28mm - 32mm (approximately 25% of travel used)


Ideally you want to be in the middle of your adjustment range when you get these numbers.  If you just flat out can't get them, or you are close, or at the end of the preload adjustment range (either full hard or full soft) you really need to get the forks re-springs for your weight - talk to a reputable suspension guy about this!

And that is how I baseline my front suspension sag setting.  Anything else while I'm at it?

Disclaimer:  I am in no way, shape, or form a suspension guy... I highly recommend you talk to a REAL suspension guy (like, Ed @ Trackside Engineering or Ryan @ Lithium).
CCS/CRA #92
07 CBR600RR - RACE
Sponsors: Two Brothers Honda, Lithium Motorsports, SpyderLeatherworks

"A lot of people go through life doing things badly. Racing’s important to men who do it well. When you’re racing, it... it’s life. Anything that happens before or after... is just waiting."  -S

Jim Moore

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Re: Setting front suspension on an '07 CBR 600RR
« Reply #7 on: July 17, 2007, 08:28:10 AM »
That's great.  Thanks.  I really appreciate it.  I have a quick question.  Are you saying that for an '07, FL1 = 120 mm?

Jason748

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Re: Setting front suspension on an '07 CBR 600RR
« Reply #8 on: July 17, 2007, 09:39:58 AM »
I have a quick question.  Are you saying that for an '07, FL1 = 120 mm?

No, The 120mm is the distance from full extension to full compression (hitting the inteneral stops) that the stock fork can travel.

FL1 is the amount of the stanchion showing at full extension.  FL1 should always be greater than total fork travel.

What this means is you will never use the last 20mm at the base of the stanchion (shiny part) as the forks will bottom out first.
CCS/CRA #92
07 CBR600RR - RACE
Sponsors: Two Brothers Honda, Lithium Motorsports, SpyderLeatherworks

"A lot of people go through life doing things badly. Racing’s important to men who do it well. When you’re racing, it... it’s life. Anything that happens before or after... is just waiting."  -S

Jim Moore

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Re: Setting front suspension on an '07 CBR 600RR
« Reply #9 on: July 17, 2007, 11:13:56 AM »
...and the light bulb of understanding clicks on above my head.  Thanks.

Flapjack_Peso

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Re: Setting front suspension on an '07 CBR 600RR
« Reply #10 on: July 21, 2007, 02:47:07 AM »
I was just getting on tonight to ask if anyone had some advice on suspension setup for a newb, this helped alot, thanks  :thumb: