[lfox]

Hey Guys,
I'm riding a 2007 CRF 250-R.
It seems that no mater what I do, I am unable to use the last 4.5" of fork travel. I'm running the minimum level of oil, (fresh), bleed the air before each ride, have the dampening screws backed all the way out, and rebound screws about midway. The bike is "factory" with medium springs, (I weigh 185). The biggest problem is high speed bumps. I do a lot of trail riding, and hitting just a small rock at speed feels as if i have no front suspension at all. The back end feels great, and the "sag" is set. Should I be looking at rearranging the valve stacks?

[riddler9]

for your weight you should not run the minimum oil, but on to your question

Oil level does not impede travel.
You can change shims to reduce travel ("shorten the fork") but not by that much.

Where are you measuring - are you trying to get the seal all the way to the axle block? To measure properly, measure from the axle block to the seal with the wheel off the ground. The go ride - get the fork dusty then do your best to bottom out the fork. Measure from where clean part of the fork ends (where the seal stopped) to the axle block. Subtract the second measurement from the first - that is your travel.

Did the problem start before or after you changed the oil? If after...
When you changed the oil, did you inspect the bushings (likely not the problem)?
The cartridge is where the travel really occurs. Did you change the oil in the cartridge, and if so, did you check the rod travel before and after changing that fluid? Did you "disassemble the cartridge" (not needed to change the fluid - you only need to remove the cap)?
Did you inspect the lower adjuster rods, and did you properly reinsert them?

[lfox]

Wow,
Thank you for all the insight. Yes I am measuring travel from the axel block up to the lowest point at witch you can see a ring mark left by the seal. It appears that the seal never leaves a mark lower than about 4.5" from the axel block, leading me to believe that I may not be using all of the travel available? I lowered the oil lave to minimum factory recommended level in an attempt to smooth out the final stage of travel, but perhaps this is in error? This has been a problem from the start, so the oil change, and level adjustment was intended to correct the problem. I did remove the cartridge cap to change oil, but went no further, and was careful to bleed per factory manual instructions.

[riddler9]

okay. The seal wiper will not make it all the way to the axle block. I "think" it should stop about 2.25" from where the pipe slider transitions to the block.

The oil level will change the rate at which the fork compresses and decompresses. If you run a lower amount the fork moves quicker (less resistance, think pogo-stick). The 07 fork is harsh to begin with, so taking a small amount of oil out does soften it. Going to the lowest allowed is making the damper work to hard which creates more heat. More heat creates more air expansion, more air expansion makes a harsher ride. So in a sense, taking more oil out causes a harsher ride as it starts off softer but hardens quickly because of the heat.

Can you tell a difference when you back off the compression adjustment on the fork or does it stay the same? If it is not changing you have a problem in the cartridge(s).

[lfox]

You are correct, the seal wiper seams to stop shy of the axel block by about 4.5"(based on wiper mark). Adjusting the compression clickers makes some difference, but not much.
On other bikes, I've always been able to "bottom" the forks, on really big, or hard stuff,(not on purpose). This bike just doesn't seem to be able to use all of it's front suspension?
Perhaps I should go back into the forks, double check the cartridges, and change the oil level back to normal.

[JimDirt]

Keep in mind you only really want to bottom out , if at all just once on the largest/worst jump on the track , the closer to and the longer time in the bottom of the stroke your bike is riding , the harsher the ride will be

[lfox]

Understood. I just want to make sure that I am able to take advantage of the full range of travel. I do a lot of trail riding, and need the suspension to soak up the bumps at moderate to low speeds.

[JimDirt]

Again , as i mentioned , using the lower part of the travel , ESPECIALLY for trail riding will make you ride in the lower part of the stroke and make the ride harsh as well as not optimize the ride , i run 2 sizes too stiff of fork springs to keep the bike UP , but i re-valved it extremely soft , i get a cushy ride , but stay up in the stroke so i utilize the valving as it is designed to be used , the more you get near the bottom , the less of the PROPER part of the valving you are using , valving works by position of the fork in the stroke , and each part of the valving is designed to open at a certain part of the travel , if the bike is going to the bottom you have blown past the part of the valving designed to hit bumps , etc, etc

If you watch Endurocross , you will see bikes use quite a bit of the entire stroke , but they stay up at the top when not compressing , and when they do compress it is for very short periods of time , because the suspension was set up to stay UP where the suspension is plusher and will absorb everything that is hit

Like i mentioned before , if you hit near bottom more than 1 time on a ride from a extreme situation , your suspension is too soft (most likely too soft of springs for your weight) and you are not optimizing anything , and the more you try to soften the ride by making it go lower , the worse you are actually making the suspension work , and are actually getting counter productive results from what you are trying so hard to achieve

Believe me , i used to think the same way you do , till i started re-valving suspension and learned how suspension actually works , and it finally sunk in that i had been doing it all wrong , and wish i could have gotten back all those years of beating myself do death

[lfox]

Very interesting! I guess my question now is; should I consider the same action that you took. i.e. re-valving, and perhaps a spring change. I'm not trying to turn the bike into some thing that it's not, nor do I wish to re-invent the wheel, I'm just trying to optimize my riding experience in the most piratical way.

[JimDirt]

Well the issue is you weigh too much for the stock springs on a 250F , the optimum weight for that bike is about 150 so you are already 35 lbs over what the bike is sprung for , so that starts the harshness because you are setting too low in the stroke , which begins the issues , it also leads (since you are too far down in the stroke to begin with) to not being able to get the clickers to work like they should

What i would do to start is to get the correct springs (front and rear) for your weight (basically what you weigh in your gear)which at 185 i am guessing you weigh about 210-215 in off-road gear (i am guessing you are wearing a backpack with stuff like a hydration pack and snacks and tools in it) like i wear for off-road , along with your boots and gear it adds up really fast

I think if you start there , you will find it easier to set things correctly and then you can begin to dial everything in from there

Your bike comes with 0.45 fork springs and 5.2 shock spring , you should have 0.46 up to a 0.50 forks and 5.4 up to 5.7 shock spring for your weight, so that 1 -4 sizes stiffer (it all depends on how much gear you wear as to the exact spring rate) , once you get that fixed , then worry about clickers or valving

[lfox]

You are correct regarding the added weight of all the gear. And going heavier on the springs seems counter intuitive at first, but your explanation to do so makes perfect sense! I will re-spring the bike, and then dial in the clickers from there. Thanks again everyone for all of the great input, and info!

[JimDirt]

No problem , also , some of the spring calculators ask for your weight without gear , disregard that and list your total weight IN gear (everything you wear when you ride , right down to your backpack and water/drinks/food) , most of those calculators are set up to compensate for MX gear , not off-road gear which weighs several times as much as MX gear, so if you put in your weight without gear , it will give you too soft a spring...

[lfox]

Got it.