Thoughts on 03 yz450f ?

18 replies to this topic
  • RedRaider

Posted December 10, 2006 - 03:05 PM


How are the 03 yz450f's? As in how is the motor reliable? How many hp do they have stock? Do they have problems with the valves? i hear alot of 4-stroke riders complaning about the valves on their bikes. I have an 04 450r i'm thinking about trading for one.

  • offrodeo

Posted December 10, 2006 - 03:19 PM


my 03 is a champ. i bought it over a year and a half ago. with lots of hard abuse i havent had to adjust my valves once. the engine is great. some people dont like the explosive power but i dont mind. easy fix with a heavier flywheel. they are very reliable and its a great by. i love my bike i think 48 hp stock, plenty

  • skiv426

Posted December 10, 2006 - 03:31 PM


I love my 03 YZ450. I have had the bike since it was new and had no problems with the bike. I love the "hit" the bike has though you can calm it down if you need to fairly easily.

  • sportbiker929

Posted December 10, 2006 - 05:24 PM


ditto to the above! love mine

  • jeffro667

Posted December 10, 2006 - 05:41 PM


I had one, and the reliability is excellent with proper maintainance, but if you're used to a Honda the power is alot harder hitting.


Posted December 10, 2006 - 05:54 PM


The first 03-04 450F's were very reliable machines, but would rip your arms off in terms of power. Be ready to spend some money on mods to tame the power curve some.

  • RedRaider

Posted December 10, 2006 - 06:20 PM


What kind of mods can you do to tame the power? I'm guessing maybe a flywheel weight but what else?

  • John407

Posted December 10, 2006 - 07:53 PM


I added a flywheel weight and went to a 47 tooth rear sprocket to tame mine down. It still pulls with the new 450s. I moto mine and if I don't get the holeshot I can't blame the bike.

  • GONE1445

Posted December 10, 2006 - 08:44 PM


hmm does anyone trail ride there 450's the 03-05's have the 4 speed is that a problem on the trails

do you find your self lookin for 5th gear

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  • sportbiker929

Posted December 10, 2006 - 09:58 PM


hmm does anyone trail ride there 450's the 03-05's have the 4 speed is that a problem on the trails

do you find your self lookin for 5th gear

only on real fast stuff

  • scottbob99

Posted December 11, 2006 - 05:20 AM


03 is a HOLE SHOT Machine.

  • Ga426owner

Posted December 11, 2006 - 05:39 AM


and when it is time to rebuild a 03 - go with a Bigbore cylinder....this makes the 03 even better....I will keep my 03 a long long time....

  • JoeWV

Posted December 11, 2006 - 05:45 AM


I only ride my 04 in the woods. No probs with the 4 speed. Love the power!

  • kawirider

Posted December 11, 2006 - 05:46 AM


03 is a HOLE SHOT Machine.

DEFINATELY. During 250 practice (the track I was at just divided practice up by your last name, not your skill level) I was with some C and B class riders and beat every one of them to the first corner.....and then I got nervous and went way wide, but my dad and my buddies said I had everybody by 2 bike lengths before I let off.

They are very reliable. I have had mine for a little over a year with no valve adjusts and still starts on the 3rd kick cold, 1st kick hot. It will even start in gear if I throw all of my 160lbs into it. Just do your basic maintenance and it wont skip a beat.

People say they handle like crap but ever since I got a revalve for mine I have no complaints.

The only problem with this bike is keeping fresh tires on it. And then when you do have fresh tires, keeping the wheel down becomes an issue....but thats a good problem.

  • grayracer513

Posted December 11, 2006 - 09:24 AM


do you find your self lookin for 5th gear

It's the same with MX bikes no matter what. When I ride the '06 I find myself looking for 6th sometimes.:thumbsup:

  • Ranger18

Posted December 11, 2006 - 11:12 AM


It's the same with MX bikes no matter what. When I ride the '06 I find myself looking for 6th sometimes.:thumbsup:

Same here.

  • sierra77

Posted December 11, 2006 - 12:06 PM


The 03-04 are pretty close. I've had mine for 2 years
and the valves are still perfect. It runs like new. A heavier
flywheel & gearing helps to tame'r down. The "ONLY"
complaint i've had is getting in really tight/slow stuff.
I put a Rekluse in and it's a trail machine! I, for one,
hate the lazy feel of factory trail bikes. I love the
hit and it makes everything a little more fun. For MX &
trails, the 4 speed is awesome. But, everyone's got their
own idea of the "perfect" bike. Just go with what you like
and make it work!:thumbsup:

  • Indiana

Posted December 11, 2006 - 02:42 PM


I agree with Sierra 100%. I own an 03 450 & I personally haven't done the rekluse thing yet but probably will. When I run a really tight hare scramble I have stalled it a few times. Once you get the gearing, flywheel weight, jetting, suspension and idle set for what you're going to do it is a great bike for woods or tight trails. I know it seems like a lot but I really don't think I would be as happy on a WR because it would feel like Sierra says too lazy & anyone who is even semi-serious about their riding performs most of those same set items on whatever they ride. I do like the four speed because even though first can be a little tall at slow speeds for tight trails it really saves shifting. Here in Indiana I don't get much of a chance to get to the top of 4th like you Californians.

  • Anssi

Posted December 12, 2006 - 12:53 PM


I ran my -03 for 180+ hours before doing the valves. I adjusted them once before that. They still measured within spec.

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