It's been some time since I cleaned the fuel screen and I'm not home so I don't have my service manual handy. But, I believe the order by inserting from the outside of the bottom of the tank goes: o-ring, filter mesh and lastly metal mounting base. The base cinches down everything when you tighten the two bolts. Try the servicehonda.com microfiche, to verify but I'm quite certain this is the sequence.

Stick with the stock pilot. It is rich as is. Whenever the pilot circuit is off tune, it seems to always be a granule of sand clogging the passage of the pilot jet.

The 165 main jet sounds like a good complement to your mods.

Edited by IvanCRF, 04 July 2011 - 10:44 AM.

Pulled the carb out again tonight. It just didn't idle well last weekend and was hard to start. Would only idle with choke on or idle turned way up, even with fuel screw turned 3 turns out.
Took out fuel screw. O-ring looked good and no obstructions. Pulled out old #45 pilot jet. Inspected it with an eye magnifying loupe. It was partially blocked. I could clear it, but had a brand new #48 and installed it.
Also, installed new No-Toil Superflow air filer without metal backfire screen. Went up another size on main to #165. Also, added small o-ring that came with the JD kit to the AP timing screw/linkage.
Set fuel screw to 1 1/2 turns out. Bike starts and idles without choke on and idle turned down.
Could only run it for a few moments because it's late. I should have time tomorrow to start it up and ride it around after work and adjust fuel screw and idle.

Edited by Sofiedog, 09 July 2011 - 11:59 AM.

Sofiedog said:

Sounds like you've got it licked. ENJOY! Now you know what the symptoms of a partially clogged pilot are!

Spent the day on some tight gnarly granite single track. Still grinning ear-to-ear with all the acceleration available of the 450X vs the WR250F.
The bigger bike didn't feel like too much more to me to move around the tight trails compared to the 250F. I'm 6' tall and 185 lbs. The bike feels like it was made for me. The extra weight caught me by suprise on some downhills and tight turns I have taken numerous times on the 250F. The extra weight is noticeable there.
Right now, biggest performance limitation is the rear tire. Still has the original 2005 Dunlop 756. Previous owner said it was never changed and I could not find any tire tool marks on the rim, so I believe him. I'll probably go with the Maxxis Desert IT 110/100-18. We ride on a lot of exposed, sharp granite along with sand and hardpack. Intermediate tires wear very quickly on the granite.
I believe IvanCRF's advice on the pilot size may be right for me. I tried the new #48, and I think it is too rich for 3500 ft and 90 - 100 F. I adjusted it rich and lean on the ride and wound up with it at a little less than a turn out, and it was still getting better as I was leaning it out. Been cleaning the old #45 and it looks good enough to put back in.
Final thought on today's ride. I would never recommend a 450X for someone's first trail bike or if they hadn't ridden in a lot of years. It's a lot of bike to use at it's full capability. I'm glad I spent a couple years on the WR250F before getting the 450X.

I recently purchased a 05-450x. I too am wondering about the mods I need to do. I bought a power core slip on. unifiter, pulled the smog off/white bros kit. I went to a 162 main. Am I on the right track? I ride the high deserts..

daveg310 said:

Put the NCVS needle in it on the third position, put one full quart of oil in the transmission so it doesn't weld itself, put some radiator guards on because the radiators are fragile and expensive, file the inner teeth of the brake pedal so it won't punch a hole in the case when you fall, don't let the kickstarter slam back and crack the case,  tighten your oil bolts by hand and Not with a torque wrench so you don't shear the oil drain bolts, use the OEM air filters since it filters the best and clean it often, you could probably use the 165 main, and read the stickies.

I have been having problems getting a clean, low rpm idle. I could start it with the choke on, but it would stall after the choke was turned off. I would have to rev the engine after turning the choke off to keep it running, then it would idle only after I had been riding for 5 or 10 minutes. If I turned up the idle speed high enough to get it to idle after the choke was turned off, it would be way too high after 5 or ten minutes of riding.
Tried fuel screw from more than three turns out to less than one turn. I ended up thinking that the motor was just "cold blooded". It also back-fired excessively.
I did some searching and reading and most said it should idle well after turning the choke off. I was getting worried that the valves may have been worn and out of adjustment, but the bike doesn't have that many hours on it. I saw a thread where someone said they installed the throttle valve plate upside down. I recalled being unsure when I rebuilt the carb. Sure enough, I took out the carb and I had done the same thing!!!
I can't believe the bike even started and ran that way. I installed it correctly and fired the bike up.
The idle speed was way high. I turned it down and the bike idles beautifully with the choke turned off, runs better, and the backfires quit. Another symptom of the upside down throttle valve plate was a lack of compression braking when the throttle was turned off. Thanks to all who post solutions on TT to help the rest of us.
I'm going out of town for a couple of weeks. Now that the bike is running great, I'll start upgrading the bike with protective components starting with handguards, skid plate, and radiator guards when I get back. I'm thinking about going with the Acerbis skid plate (I don't like the sound of aluminum skid plates) and the Mohard radiator guards (they look nice!). I also like the look of the Acerbis Supermoto handguards.

Sounds like you are gunna have a good bike. Enjoy it, I enjoy mine. You sure have a lot of free time to do all that work. Have fun!

Just mounted the Acerbis handguards and skid plate (pics in Garage) this week. Also, switched fuel screw to R&D flex-jet. Much easier to adjust the idle mixture compared to standard rigid aftermarket screw.

Got out to ride again today. Bike is running well since I put the carb back together correctly.

Stock #45 Pilot jet seems fine for my riding conditions today 4000ft, 90F, 30% humidity. Seemed to run, idle, and start well with ~1 turn out.

Going riding with my girlfriend tomorrow. She wants to ride my WR250F instead of her CRF230F. I'll let her ride it, but I'm going to keep it. It's still a lot easier for me to ride it on tight trails compared to the 450X.

Sofiedog said:

:worthy::thumbsup:

Sounds like a lot of fun. Ive had two like new 05 X's and my brother has one. They are very fun bikes to uncork. It is amazing how they transform with one afternoon in the garage and a few misc items.
I know it was posted on here all ready but it is a really important thing so you dont waste a fun day. The rear brake lever needs to be modified or you will lose your oil over a silly rock or object pushing it into your case. It happend on two of the bikes we've had.

There is so much info for the X's on here it is ridiculous. Have fun!

motoXXX43, thanks for the reminder on grinding the brake lever. I think Krannie or someone mentioned it weeks ago, but I've been procrastinating. I finally ground them off after my ride today. Ground off the inside serrations on the front and back of the lever tab and chamfered the inside edge.
My girlfriend did well riding the WR250F today. She doesn't want to ride her CRF230F anymore!! The 250F's have much better forks, shocks, and chassis. She wants to go look at a low hours 2005 250X tomorrow that she saw on Craigslist this afternoon.

Sofiedog said:

Ooooh, a CRF250X or a WR250X? The Wrx is a dog....

That's great! Something about those 250X's!!!

We both got a chance to ride my 2006 WR250F (steel frame), a friends 2007 WR250F (alum frame), and a friend's 2005 CRF250X back-to-back on a small, tight, private MX track.
No doubt, the CRF250X has the snappiest motor. I don't think the 2006 and 2007 WR motors are any different. My steel frame WR felt the most stable, but felt "heavier" and more difficult to turn. The CRF250X felt most nimble with the 2007 WR feeling more like the CRF250X geometry than the 2006 WR geometry. My girlfriend liked the "light" feel of the CRF250X. There's one in town for sale with low hours, completely stock, and in "like new" condition (he says) for $2500. We're going to take a look at it tomorrow.
She's excited. She feels the CRF230F has been limiting her and holding her back and she had such a blast on the WR250F today she couldn't stop talking about it. As much as she likes the WR, she likes the color red better:smirk:

Such an informative post, just read it all! Nice that you got the X all dialed in! I'm in the process of changing my XR400 to an 450X, sounds like you're having a blast in the X.. Nice!
BTW, how was the 250X?

Just got a new rear tire on the bike. Installed a Maxxis Desert IT 110/100-18. Been wanting to try one because of the gnarly granite infested trails around here. Downside is weight. It is a very heavy 14.5 lbs! The worn D756 110/100-18 weighed 11.5 lbs. I weighed a new Dunlop MX51 110/90-18 (made for a 1.85 rim) and it weighed 12.0 lbs.

The original 6 year old tire wore pretty quickly after about six rides of about 25 mi each on the gnarly trades. The rubber was getting a little hard and "chunking" off. Replaced the rim strip and installed a new heavy duty Kenda Tuff Tube.

Also, had a couple of lightweight Motion Pro rim locks. The original wheel only had one rim lock installed, although there was an additional hole in the rim with a small rubber plug. Been running two rim locks on my WR250F and it enabled me to ride out of the trails with a flat for about 15 miles without damaging the wheel or tire. Decided to try two rim locks on the 450X since I don't like to carry tire tools and a spare tube. I have a hard enough time changing a tire in my garage with a tire rack and long irons. I can't imagine the hassle of changing a tube on the trail. The sidewalls on the Desert IT Maxxis are very stiff and difficult to flex enough to get a tube out and back in. I usually put the tube in first when a change a tire.

Rear wheel bearings and seals looked and felt good. Packed more grease into the gap between the bearing and seal.

The front tire still looks good, but I may replace it soon. I've been wanting to try the Dunlop MX71 front tire. Also, still need radiator guards. Still leaning toward getting a set of the black anodized Mohards. I haven't fallen hard yet...

Checked out a couple of 250X's for my girlfriend. One was a "low miles" 2005 for $2500 and was poorly maintained. It had a rusty chain, a dirty air filter, and dirty oil. Another was a beautiful, clean, never trail ridden, and low miles. He wanted $3200. I offered $3000 and he wouldn't take it. My girlfriend continues to enjoy the smooth ride of the WR250F. We rode some difficult, rough, rocky climbs and she did well on it. She stalled a couple of times but was able to get her feet down, hit the button, feather the clutch, and get back on her pegs.

Had it for 5 days now.

Shelf queen?

Acerbis hand guards
Hammerhead controls (c,
ASV levers
FMF header
WB slipon
Smith carbon fiber pipe guard
Works connection skid, radiator guards
JD kit, (white/whib/whist)?? carb spring
Black excel takasagos
red RAD hubs
New SS valves in 09
40-50 hrs on top end (est)
clean airbox, normal wear
Super neat guy I bought from, TT regular.
3000k

Thanks to everyone who gives all the good info on here. I used TT alot in researching my purchase.
Starts right up and really screams. Had been laid down a few times but overall really clean. Planning on plating it for street(brake switch,trailtech, airhorn:busted:) I live in Phoenix (just moved, west valley) looking for halfway normal cats who want to ride/wrench/beer.

P.S. fairly light knocking in engine normal? occasional back fire on accel?

Hi Pizzmann,
Nice bike. Enjoy! Probably good value for 3Kwith all the aftermarket parts.
The wildcard, for me, is the state of the valves when you buy a used bike like the 450X. You either have to find a garage queen with low hours or find one that has recently been rebuilt, otherewise you have to factor in the price and time for a rebuild.
I bought mine in PHX area too, even though I live in Tucson. PHX has a great selection of used bikes to choose from. If you're ever down this way, check out Redington Pass. Great set of trails. Need OHV tag.
Regarding the "knocking", the 450X motor is more noisy than my other bikes. That's one of the reasons I put on a plastic skid plate instead of an aluminum plate to reduce the reflected engine noise.
I changed my oil on both sides as soon as I got the bike to inspect the oil and ensure I didn't see any sign of bearing wear.
Once I got my jetting tuned, the bike has been a pleasure to start and ride. Small amount of backfiring on high speed decel while compression braking seems to be normal. I would say that backfing during acel, per your post, is unusual?  Others will have to comment on that.

Got a chance to ride today with new rear tire. As expected, made a big difference when the rear tire doesn't spin so much when accelerating.
Going to put a new front tire on next. Front end seems to slide excessively when turning compared to my WR250F.
Also, cleaned No Toil Super-Flo air filter after riding. Seemed to seal very well against mounting base. There was an obvious imprint from the raised lip of the air box mounting surface on the airfilter mounting surface. The imprint was continuous with no obvious air flow around the filter.
Most of the airflow/dirt pattern was on the top of the filter under the airbox intake holes and the additional holes I added.