YZ450F for the trails? Would this kick my butt?

Been riding 250-400 2 smokes for years. Bought a Yz250f 2 years ago just for fun. Now it's time to hand it down to my 14 year old. I'm deliberating getting a CRF450 or converting a Yz450F for the trails. I know, why not an EXC450, or WR450? I hate the weight of the big trail beasts. Thinking about doing these mods: FMF Q muffler; 16oz flywheel weight; Z start auto clutch; and maybe, though not sure, a set of WR cams to smooth out the power. With the z start auto clutch the four speed doesn't seem like it would be a problem with stalling, etc. Just chug along. I've been thinking about the CRF for a long time but don't want to deal with valves and blowing oil. I know some Honda guys hear will tell me different, but I ride with Honda guys who know otherwise :cry: The Yamys just fit me better...ergo wise. I'm 6'1" 215# with gear on. I mainly trail ride and can find a good deal on a used YZ450F: $3800-4400 around where I live. Also, what's the main diff. between 03 and 04? I know they added flywheel weight and changed ignition mapping for 04, but what else is there? What do you guys think? Would this thing kick my but on the trails? :cry: :cry:

I believe some of the differences are ti pegs,better larger forks and they smoothed out the power on the 04.I have not ridden an 04 but own a 03 that i trail ride.I used to ride a 93 yz250 that had a brutal hit it was a little modified,the 450 to me is great a whole lot easier to ride than a two smoke and i dont think i would not be happy with less power.First gear is pretty tall so i geared mine down quite a bit,it won't go 75mph but is fast enough on the trails.I added a big tank ,bark busters and a spark arrestor and love it!

50 tooth rear.

4 oz. Dr. D flywheel.

Dr. D "D" shape can.


clarke tank.

hang on!

fun, fun!

I owned an 00 YZ250 and the last time I raced it at a GNCC I was in 3rd place before I crashed and spent 2 days in the hospital and 6 months of rehab. After that I bought an 01 EXC250 and the then the YZ250F. I really don't want the massive hit my YZ250 had...it also was modified and ran like a raped ape!!

YZ450F feels top heavy compared with YZ250F if you mainly trail ride like you said. Even though you modify it. A 2-3 hour race beats me up twice as hard as it would with the YZ250F. I like MX better and power in sand, so I stay with 450. JMO.

If the woods are tight at all, with the 4 speed, you better be good at riding the clutch!!

I have seen quite a few CRF's tamed down enough for woods but I have yet to see a YZF tame enough.

If you are going to do the WR cams with a z start you should be fine. I have a YZ426 with a z-start with an YZ 03 cam, FMF Q and it works great. The z-start makes the bike so much easier to ride on the single tacks, its more like a PW426 now. :cry:

MX bikes in the woods scare me.

You guys running MX suspension in the woods?

Steering dampers or not?

Without suspension and dampers I'm not surprised you crashed and wound up in the hospital.

I thnk you must be tough and really fast to ride a YZ450 in the woods for sure.

In my opinion, it's alot easier and less expensive to make a WR450 lighter and more MX oriented than it is to make a YZ450 more trail oriented. Plus, the YZ will never have a wide ratio tranny. On the WR, you can take the e-start components off, lights can come off, you can replace alot of steel parts w/ carbon fiber and Ti, etc. Go w/ a Ti exhaust, etc.

I ride mostly woods now on my YZ450F. I have a 4oz Dubach flywheel and suspension mods. I typically am just fine in the woods but in the extremely tight s-turns there's a lot of effort getting the beast through. An auto clutch would make a world of difference but my big hesitation is not being able to put the bike in gear on a hill while the engine is off and have it not freewheel down the hill. It's probably better not to stop halfway on a hill but admittedly I occasionally don't make it up some of the steep ones on the first try. But shhhh. That'll be our secret!

You had better find someone that will let you borrow one and try it before you go and buy one.

My friend has a 03 and 04 YZF450, that he uses for 98% Moto-cross. We went to a moderate trail system and he was really surprised. Honestly not bragging, but we really roll close to a GNCC pace through trails, and he was fighting it so much that it kicked his tail.

We got into a tight section and I heard what sounded like a firecracker just a few feet behind me. I stopped and turned around, and he was off straightening out his forks. Stock first gear on these things is really high.

I find myself fighting my CRF a lot also but the 450 power is awesome. :cry: :cry:

You may be able to convert it over the way you want it for your riding but the trails here are way to tight for a 4 speed. Good Luck. :cry: :cry:

MX bikes in the woods scare me.

You guys running MX suspension in the woods?

Steering dampers or not?

Without suspension and dampers I'm not surprised you crashed and wound up in the hospital.

I thnk you must be tough and really fast to ride a YZ450 in the woods for sure.


Revalve is a must.

I'm a 190 pounder so the stock springs are ok, but revalve did help tremendously.

The stability of this machine is amazing. No damper. Set top of fork 5 mm above top of triple clamp. Won't turn like a KDX200 in the woods, but then again not much else does either.

Handful at times. This is not a good woods bike for the "ham-fisted".

Mark S.

i have an 04 450 and that thing is a beast to ride in the trails. honestly i dont even like it. its not fun. its so great for the track but when my friends decide to go to the trails, i go home bc its a little scary w that much power ready to unleash on such a tight trail. if you are going to trail ride i would look for a different bike. theres no way around it, that bike is meant to be a pure mx bike. good luck

I have an 04 YZF450 that all I do is race Hare scrambles. All I have done is re-valved suspension and gotten a bigger tank. I changed the gearing to 14F 46R. I have no problems stalling in the woods. I had a 99 YZF400 that I raced with for 5 years in the woods and never had any problems. The 450 is much more fun in the woods, due to it being lighter. I changed the gearing so I could pull 2nd longer. I don't scream my bike thru the woods, I just kind of chug along. I race Vet A class.

Eric, you gotta have some iron arms and you are in great shape, what? You must have Finnish blood in your vanes..?


I took my 2003 YZ450F for a woods ride last night. The bike has stock gearing and the suspension is set up for MX but it still rode great. I never left 2nd gear all night, darn near like having an automatic transmition. The trail was whooped out bad so I think the stiff suspension was somewhat of an advantage. What a blast, I need to ride the woods more than once or twice a year. I forgot to mention that I did add a 10oz flywheel weight, I like the flywheel weight for MX as well as the woods.

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