I want to tune the suspension a little for my riding style. I weigh 185lbs and like to ride mostly ride slower, technical trails. After the last ride I put the bike on a stand and extended the forks and opened up the bleed screws. I could hear air escaping.
I checked the positions of the compression and rebound damping screws and they were in their stock positions according to the manual. I want to soften the initial impact of hitting rocks and roots at 1st and 2nd gear speeds, so I backed out the fork compression damping a couple of clicks.
The manual says the stock springs are designed for 150-160 lb riders, so I may go to the next heavier spring, eventually.
I haven't checked the fork oil level. However, there are no signs of leakage, so I may not change the oil, even though it is 6 years old, until I need to replace fork seals.
I checked the "race" sag as described in the manual. It was slightly more than the specified 100 mm. Doesn't suprise me if it was factory set for a 150 lb rider.
Rear shock damping settings are also stock. I went ahead and turned out the high speed compression damping adjustment a quarter turn. I'll test ride it next week.

Sofiedog said:

The Showa forks have three issues:

- mid stroke harshness
- overly stiff pressure spring (first 2" of travel)
- bad oil- it's junk right from the factory

--You can improve the mid stroke harshness by adding stiffer fork springs. You can solve it by having the fork re-valved.
--You can improve the initial stroke by putting in a softer pressure spring.
--Replace the fork oil. It only lasts about one year, even if you don't ride the bike. Air gets into the oil and cavitates it, it oxidizes, and it turns into sludge in 5 years.

Go with the stock settings to start with. Consult your service manual. Of course you have one.
Go out 2 clicks  out from stock on everything for very slow, and 2 clicks in from stock on very fast riding.

Try not to mess with the high speed compression damping on the shock too much. It is strongly tied to the low speed compression and the rebound. High speed mean high 'shaft speed'; square edge bumps and the like. Nothing to do with bike speed.
1/8 - 1/4 turn is a lot.

If you combine your sag settings (98-105mm) with a good 'f ' series front tire (for heavier four strokes) you will find the bike suddenly is able to turn consistently. You fork rebound needs to be not too soft either.

Krannie said:

Krannie, I have seen you reference a F series front tire a few times.  What it a F series tire?

Mike

I dont have a service manual,l. What is the stock click settings for the 2005 450crx's fork's compression/rebound.

MStef66 said:

"F" series means Four Stroke Specific. Not always listed as such.

EG: Dunlop 739 and 739fa.
http://www.dunlopmot..._tire.asp?id=11

All Bridgestone M series tires are 'f' series tires.

Krannie said:

Interesting, I didn't realize there was such a classification.

Thanks,

Mike

Worth it for faster single track 50%  slow technical 20%  and 20% street riding. I am making a list of next upgrades. Aside from a complete engine overhaul next spring (plan on riding a s@#^ton this winter), I want to improve handling, I have zero experience with Race Tech, should I have gold valves installed and/or just a reputable susp. service done? Bike steers fine, I just want more predictability under my bars.

Thanks again for your inputs, OH , and I am not trying to thread jack. I just have the attention of the class/instructors

Krannie, thx for taking the time to provide the detailed reply on setting up the front forks.

I'll go with the stiffer 0.49 kgf/mm fork springs for my weight and change the fork oil at the same time. Unless I hear otherwise, I'll go with the standard Pro Honda HP Fork Oil 5W and the recommended oil quantity in the manual for that spring.

I'll go back and start with the stock fork damping settings and then go out 2 clicks out from stock on compression damping to soften "square edge" bumps. I want the forks to absorb hitting rocks and roots at first and second gear speeds instead of bouncing me off line. (Mostly rocks out here)

I'll also look for softer "pressure" springs. I'm assuming that's the smaller spring in the "Fork Cap Assembly" inside the "Fork Damper".

I'll reset the high speed compression damping on the shock and adjust it out ~1/16th turn, again to soften the "square edge" bounce.

I'll adjust the rear sag setting to within 98-105mm. It was a little higher.

Of course, I'll do this after I put on the new MX71 front tire. I should have that on next weekend:ride:

Sofiedog said:

In a few months, you will be posting about getting even more out of your suspension. This is normal! The chassis set up from the factory is very generic and unbalanced. The springs and clickers take you about 25% of the way to fully realized suspension system. A little magic to the shim stack and bottom valve and you will be golden. It's not about going faster, all though you will be able to, it's about exerting less stress and concentration when riding. Funer-er.

Pizzman said:

Order of importance, IMHO:

1. springs for your weight and fresh front fork oil
2. Rear sag at 100 mm
2. softer fork pressure spring
3. re-valve shim stack away from 'generic' stack that comes from Showa, on front and rear (<< HUGE IMPROVEMENT<<)
4. modify base valve holes
5. replace base valve with upgraded valve

daveg310 said:

Nominal positions are listed in Owner's manual, as well.
Rebound damping on bottom of fork. Nominal position 7 clicks out.
Compression damping on top of fork. Nominal position 14 clicks out.

Just installed new Dunlop Geomax MX71F, 80/100-21, front tire. Used a new Kenda Tuff tube (1 lb 15oz) and a new Kenda rim strip. Re-used original rim lock. Seemed to be in good condition. Wheel bearings seemed ok. Re-greased the dust seals.

Went riding today with the new tire. What a difference! I was initially disappointed with the CRF450X handling because the front tire seemed to break loose too soon and very suddenly. The slide didn't seem to be controllable. The new MX71F holds on longer and feels very controllable when sliding.

I like it a lot. I'm going to use it on my other bikes when they need a new front tire. It's inexpensive, light (~9.0 lbs), has a durable tread compound, and handles well. Not much more to ask for in a tire.

Glad I replaced the tires before I started addressing suspension and handling tuning. Tires make a huge difference with the feel of the bike. I have the stiffer front springs on order (51403-MEY-003) and bought a couple of quarts of Honda HP 5W fork oil. Also, ordered a Motion Pro 50mm Fork Cap wrench.

Now that I have new tires, I'm going to set the rear sag correctly, install the recommended fork springs for my weight, and replace the old fork fluid. I'll then start tweaking the damping settings. Sounds like fun.

Cool I was having a hard time making a decision on the next tires I am going to use., do you take them on road at all?

The MX-71 tire's rock. I have them on the KX450 (rear) and WR450 (front).
Not as 'hard terrain' as other tires, which is good. Soooo predictable and easy to feel underneath you in these dry days.

Krannie said:

Krannie hit it on the head exactly. I have had these tires on my bike now for 5 rides (desert and track) and they grip hard and predictably every time.

Still waiting on fork springs. Received a package with one fork spring in it from Chaparral and the invoice said the other one was backordered. Who spends the time and money to ship someone one fork spring!!??!!

Decided to install new FMF Ti Powerbomb header (pic in Garage) while I wait for fork springs. No problems with installation. Mated up cleanly and easily with FMF Ti Powercore muffler and mid-pipe. Installed with new exhaust gasket. Looks nice!!!

Also, installed a Moose E-line Carbon Fiber Heat shield. Adds a little carbon fiber bling.

Stock header and heat shield weighs over 2 lbs. Ti Powerbomb and Carbon Fiber Heat shield with mounting hardware weighs less than 1 1/2 lbs. So, that's a 1/2 lb savings to add to the muffler weight savings.

Been running the recommended JD jetting with the #162 main at 4000 ft elevation and 90 - 100 F temps. I tried the #165 main, but the throttle response felt a little crisper with the #162. Suprises me how spot-on the JD Jetting settings are for the main and needle position. I'll try the #165 again with the new header.

Sofiedog said:

165 main should be just right, if not a little small.
Throttle response is from the needle, needle jet, needle position, and accelerator pump circuit. Until you put in a 50 leak and a merge racing a-pump detent spring upgrade, you have NO idea what kind of throttle response this bike is capable of .NIGHT AND DAY.

Been real happy with the jetting. Bike starts easy, idles well, doesn't flame out at low speeds, and accelerates crisply. JD Jetting recommendations seem good.

Been riding with the #50 leak in it. Had tried a couple of different needle clip positions, but the recommended middle #4 position seems to work best. Don't have the Merge Racing spring. Been running the O-ring mod. If you think I could tell the difference between the Merge spring and the O-ring mod, I'll put the spring in.

I'll need to get the bike onto the open road to ride WOT to check the main. That'll be fun! I'm sure it'll feel fast even if it's lean. I'll try the #165 and larger.

Edited by Sofiedog, 25 August 2011 - 04:58 AM.
corrections

Sofiedog said:

You might not feel a difference with the ring vs the spring, but the spring always feels the same, hot or cold, and will not break. The ring gets soft in a few minutes.

With the exahust mods you did a 165 should work better (altitude depending). If you are really brave, try reaching down to the choke , and get back on the throttle hard, to see if it runs better......as in bigger main.....

Great idea on the choke. Hadn't thought of that. Otherwise, it's hard for me to tell between a small change on main 162 to 165.