03 Cr250 Set Up

Walt Hollis · Mar 9, 2003

Need some help on my 03 CR 250. This is the first new "modern age" bike I have had, previous MX bikes were beaters. I am 165lbs, beginner / intermediate vet mx rider. I set up the suspension based on all the magazine test recommendations. It works great everywhere except on fast straights. It won't settle down and hold a line, the bars almost tank slap out of control. I could go faster but I have to let off as it is about to go out of control it gets so bad. The fork settings are 14 out on compression / 15 on rebound; the shock is 8 out on compression / 5 on rebound and 2.25 turns on high speed compression damping.

Most folks say I am not fast enough to justify revalving, not sure if that is what it takes or if my set off is just off.

Thanks in advance for any help.

- Walt

marcusgunby · Mar 9, 2003

Normally if the set up works well everywhere else, then you just need to pull the forks through in the clamps a few mm.I go in 3mm stages.It makes a big difference.

IRISHCOFFEE · Mar 9, 2003

i would say that your ''most folks" are just plain dumb! i am not fast either but have found that good suspension setup is of far more value than horsepower. trust your instincts and have some one you can depend on fix your suspension. do your homework first.

DKT735 · Mar 9, 2003

I assume you are experiencing what I call head shake. (As opposed to when the front end is going straight and the rear end is swapping from side to side.) Is the head shake happening under accelleration, maintaining speed or under braking. From my experience, make sure the air is bled out of the forks; make sure you have fresh or reasonably fresh oil in the forks; check your sag, try running more sag in the rear.

A few years ago I my suspension revalved by a popular aftermarket manufacture and the forks were terrible until I drained and refilled them. Came to find out that they didn't put enough oil in one of the legs. Mistakes happen.

Let us know how it turns out.

russ17 · Mar 9, 2003

Walt ! I agree with Marcus Also check and make sure your chain adjusters are lined up, If there off this will also cause head shake at high speeds. just to show you that the rear can effect it. I was doing some testing and kept getting head shake kept changing adjustments ect even tried a different set ups still kept getting head shake. well to make a long story short I had a broken bead on the rear tire, check the simple things first

dbrace · Mar 9, 2003

Springs should be ok for your weight. Any decent suspension tuner will be able to throw in a crossover to give u some initial plushness, but this will be far from perfect. consider a total revalve from someone u trust.

Walt Hollis · Mar 10, 2003

Thanks for all the advice. I like the suspension all around exept for the shake and tracking issues. (whats not to like, my last bike was very tired 94 KX 250) I usually ride a track where the fast section is a downhill and this weekend I went to a new track where the fast section was flat and it did the same thing. It seems as soon as the speeds get up into the 4th gear range it gets ugly.

Just checked the fork height, I have 6 mm showing now, so I will try 9mm this weekend for starters.

On the revalve way to go, is it bad to do the forks and shock at different times (ie budget) or is it best to have them done simultaneously? And if it is OK to have them done one at a time which would you recommend getting done first, shock or forks? The vendor would obviously be the same but I was wondering if I could spread out the money hit.

Thanks,

Walt

marcusgunby · Mar 10, 2003

wait, wrong way to go-you want 3mm showing.

shockdoc · Mar 10, 2003

Actually Marcus, I think he's going in the right direction. If it's headshaking under accelerating or at speed then I usually will raise the forks a little. Now if it's headshaking while breaking then I would lower them. Let us know how it works.

doc

marcusgunby · Mar 10, 2003

shockdoc i should have asked if its deceleration or acceleration-normally crs shake their head under breaking so i assumed its that, walt if you could let us know.Also the only bike i ever had shake under acceleration was a RM-it scared the crap out of me.Throttle on and a bike should be stable-how do you overcome shaking under acceleration??(if its actually in the middle of a race) you cant open the thottle:(

shockdoc · Mar 10, 2003

Ya sorry Marcus, I guess I was assuming under accelerating. I know what ya mean on the old RM.....had a 95 RM250 that liked to shake it's head. It was like my 96 CR250...."A blurry-eyed dance with the devil" every time I rode it.....LOL

doc

Walt Hollis · Mar 10, 2003

The headshake occurs under acceleration, no problems under braking at all. Please clarify the raise and lower, at this point I am showing 6 mm of fork tube above the top clamp, if I have this correct I should try increasing that to 9mm, or is it decreasing that to 0mm (ie + / - 3mm).

Thanks, Walt

dbrace · Mar 11, 2003

Would headshake under power suggest that the forks are too hard in the initial part of the stroke? If they cant compress they can only twitch from side to side. Try going 4 to 6 clicks out (softer ) on fork compression. Set fork rebound on 12 clicks out. Check your rear shock race sag, set to 100mm, the shock can cause fork problems if the suspension is out of balance.

DEANSFASTWAY · Mar 11, 2003

Walt you might also try to adjust or remove regrease and readjust your steering stem bearings when theyre new theres not much grease put in there from factories. On a few CRF 450s Ive seen the bearings be loose I think until the races take a set in the aluminum . maybe your CR also or maybe just the 450s heft or heat at the frame .Maybe like MG said try dropping the forks in the clamps a bit or running a bit more sag at the rear . for a bit more rearward weight bias . I gotta tell you all this story about head shake . There this kid I know who has to have all the trick stuff hes young and he rides pretty good . Well call him the Carbon Fibre kid , So Carbon Fibre needs me to build him these trick wheels for his radical 125 . So I get the rims and spokes and stuff and he mail orders new tires and tubes . I put it all together and he has these super heavy Bridgestone tubes , you know the flatproof type ,thich and heavy good for like Baja 1000 or the 6 days Enduro or something . Well, I get it all together and he puts them on and his first time out the bike has real bad headshake on fast straights . He almost cant ride the thing you know. So his buddies are like thinking the rim build is bad and its wobbling , but we took the front tube out and replaced with a regular tube and the problem was cured. I would have just balanced the tire but he didnt want any weights on his spline drive spoke nipples.

Walt Hollis · Mar 11, 2003

I had the bike torn apart by my local shop before I rode it and had everything lubed.

On the sag setting, I need to check that again, is there an on-line how to on that posted anywhere?

Thanks, Walt

Faded · Mar 11, 2003

HERE is one. :thumb:

Walt Hollis · Mar 12, 2003

My sag setting came in at 111 with street clothes on so I figure it would be greater if I had all of my gear on. Should I gear up and measure again or should adjust down to a little higher than 100 since I am shy a few pounds?

Would the the sag being changed from 111 to 100 make a noticeable difference? I will see this weekend, but just curious in advance.

Thanks to all for all of the help.

- Walt

bscottr · Mar 12, 2003

Walt,
It can make a BIG difference (111 to 100 +/-). I'd make this change and ride it prior to making the fork adjustment.

Suit up and fill your tank half full if you want to be fairly precise with your measurement.

BTW: What's was the free sag measurement? More importantly what is the free sag measurement after setting race sag?

Doc,
If I remember correctly, you prefer to set the free sag first and then check the race sag. I can't remember why you preferred this method. Dang CRS! ;) Can you remind me? Thx

Walt Hollis · Mar 12, 2003

Free sag is at 37 mm. Target should be 20 mm. I will set the sag tonight with gear on and then see what the free comes in at (wife help permitting)

Is 100 mm of sag a good rule of thumb on any mx bike? Specificially I was wondering if I should set up for that number on my son's KX60, or do smaller bikes have a different target number?

Thanks,

Walt

bscottr · Mar 12, 2003

Originally posted by Walt Hollis
Is 100 mm of sag a good rule of thumb on any mx bike? Specificially I was wondering if I should set up for that number on my son's KX60, or do smaller bikes have a different target number?

100 is good, not sure on the little guy though.

Jeff Howe · Mar 12, 2003

Originally posted by bscottr
Doc,
If I remember correctly, you prefer to set the free sag first and then check the race sag. I can't remember why you preferred this method. Dang CRS! ;) Can you remind me? Thx

That may be me you are referring to. I don't measure my sag. I set mine by ride and feel method. My advantage is that I have a whole shelf of springs to play with. For example I started with a 5.0 set up some free sag and went and rode it, adjusted it rode it some more. Didn't like it. 5.2 same deal, 5.4 was the ticket for me, though I actually raced my 5.2 for over a month. The reason I set up with free sag is that you don't want the spring wound so tight it tops out. Oddly enough at the time RT spring search recommended that I run a 5.0 and I can honestly say that performance wise it lacked seriously.

Jeff Howe · Mar 12, 2003

Just to clear that up a bit more....the average guy without the option of playing with different springs needs to use race sag to determine if the spring is rated correctly for his weight. To this day...(going on my 4th season with the 00 YZ 250) I have not measured the sag on my bike once.

bscottr · Mar 12, 2003

Shockdoc / Shocknut my apologies to you both. CRS compounded is a terrible thing. :o

Thanks Shocknut for the explanation. :thumb:

Just for the fun of it……you do the ride a feel method. You are obviously experienced and have your bike dialed in very well. We all know that most sag measurements will usually be in the 95-105mm range. (I know some folks prefer much less and much more than this range). 95mm is likely to turn faster than 105mm. 95mm is more likely to head shake under braking than 105mm. There are other trade offs as well.

Would you be willing to break your 4 year streak and measure your race and free sag for us? ;) I’m interested how the reading comes out to see if it falls in this range (99-105mm).

Thanks,
Scott

Jeff Howe · Mar 12, 2003

I guess I could at some point, but I change mine for different tracks. This is what most guys overlook. This is a personal preference tuning adjustment just like a clicker. For example when I ride sand I may run more sag but firmer compression and slower rebound. When I switch to blue groove (hardpack) I run less sag and softer compression and faster rebound. When I ride bluegroove I like more front end transfer and the front to dive more and thats not something you want in sand thats for sure. There is no need to get stuck on a number as THE setting. Heck, my setups are changed between motos at some tracks even. Sag is going to adjust your chassis attitude and like everything else if you ride without change you will never know if it can better or not. So, what works for me may not work for you and your riding as our postioning and style may be different.( I'm old and fairly slow :)

This is a peeve of mine of sorts...I hear guys telling their customers to leave the adjusters where they are after the guy sets up the bike. That may be fine if the track surface never changes but in my locale we have a wide variety of track types to ride on and I can guarantee that a good harpack setup will have you on your head on our worst sand track.

On Saturday practice days I spend my time getting the bike dialed. Now, it can be just a matter of looking at a notebook, but I still try different settings instead of just wasting my time doing laps all day and I'm usually busy with those guys smart enough to come by for the advise.

bclapham · Mar 12, 2003

hey shocknut, just a little Q for ya, but please dont think i am looking for a handout, but a tad of guidance or inspiration would be nice!:)

i see you are running an 00yz250, i have the 01 and the previous owner put on a 5.6kg rear spring but didnt revalve the shock. i am around 220lbs and the race and free sags are fine, the spring calculators seem to be miles off! i am begginer class MX rider and have have looked into doing some adjustments myself, the next up will be the shock, it just doesnt feel right, i am constantly thinking it is way too stiff but in hindsight i think it is riding too low and packing up and giving the stiff feeling, if i wind in the compression, it just feels nasty!

i am in 2 minds on what to do, i could just send it to be revalved, but then i will learn nothing, so where would be a good place to start the adjustments on the shock? are there any idocyncracies with this setup that can be easily ironed out with clicker adjustments, or is my higher weight just putting be out of the envelope of the current valving?

i know the gentlemens rules of conduct in here, please let me know if i have overstepped the mark and i can hit the edit button,;)

thanks in advance

bruce

03 Cr250 Set Up

Walt Hollis

marcusgunby

IRISHCOFFEE

DKT735

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russ17

dbrace

Walt Hollis

marcusgunby

shockdoc

marcusgunby

shockdoc

Walt Hollis

dbrace

DEANSFASTWAY

Walt Hollis

Faded

Walt Hollis

bscottr

Walt Hollis

bscottr

Jeff Howe

Jeff Howe

bscottr

Jeff Howe

bclapham

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