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How good is the KX450F?

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Posted by: SADude---------------------

I have a friend that is looking to change to 4-stroke and likes the look of the KX450F.

Please can you give me information on reliablity and how good it is for off road and Harescrambles use?


Posted by: destructo---------------------

ive been doin some research on the kx450's, the problems ive found are weak factory clutch springs, it is said that after any hard riding, like three of four races the clutches will start slipping. and also the wrist pin that goes through the piston is actually to hard and will crack break. Ive always been torn between kawis and yamahas, so i picked up a mint condition 05 yz450f, and love it.


Posted by: Mackeymx---------------------

I have a kx450f, and i love it, i have a good 10 hrs on it and no problems what so ever, that wrist pin issue is only on the early production bikes so far. Go for it, its an awesome bike.


Posted by: nephron---------------------

Quote:
that wrist pin issue is only on the early production bikes so far. Go for it, its an awesome bike.


How do you know?


Posted by: JST122---------------------

I have an 06 KX 450F and the bike rocks. I have raced mine 3 times and run several practice days on it since I bought it. If it would ever stop raining out here I would have more time on it. The bike runs excellent and is just as solid now after three races and numerous practice days as it was for its first ride. Fortunately I have not experienced any of the problems that have been mentioned above and my bike shows no signs of problems (knock on wood). It starts just as easy as my 2 strokes do and it is the most stable tracking bike I have ever ridden. The biggest surprise I have had with this bike is how well it handles. I am sure that you have heard people comment that the 4 strokes dont handle as well as the 2 strokes, but that is a thing of the past with the new four strokes and in particular the RMZ and KXF. These bikes turn and handle in the tight stuff and in the sweepers every bit as well as my 2 stroke does. It was also a very easy adjustment coming off of my KX 250 and making the transition to the 450F. Up to this point I could not be more happy with my choice. As is the case with any first year model, time will tell the story as far as durability and reliability go but I have absolutely no complaints to this point.

As far as off road and harescrambles use goes I cannot give you a good report on that. I only use my KXF on the track. I can tell you that the bike is a four speed transmission and therefore the initial gears feel taller and I would suspect that for off road use in tight trails you would probably need to make some gearing changes or even add a fly wheel weight to make the bike more user friendly and suitable for that application. The taller gears are helpful on the wide open MX track but inorder to maintain the same power characteristics at slow speeds in the woods some changes would probably need to be made in order to make it an ideal woods bike if thats what you are looking for.


Posted by: kawicam125---------------------

http://www.motorcycle-usa.com/Artic...ArticleID=2583#

http://www.transworldmotocross.com/...1111880,00.html

as they say, its got an all new aluminum perimeter frame, two-piece shrouds, titanium footpegs, brackets, headpipe, and heat sheild. its weighs about 220lbs. dry. its got a 38in. seat height and kayaba suspension( fork and shock). this bike( obviously) has a 449cc engine. its got exceptional handling and stability and its winning all of the shootouts and tests. id say go for it!


Posted by: nephron---------------------

Quote:
It starts just as easy as my 2 strokes do


Would you like to put your hand on a bible and say that again?

BTW, as far as scrambles are concerned, you might want to briefly visit Destry Abbott's website and look around. He just went to a 450f.


Posted by: Rich Rohrich---------------------

Quote:
Originally Posted by nephron
Would you like to put your hand on a bible and say that again?



I will.


Posted by: JST122---------------------

[QUOTE=nephron]Would you like to put your hand on a bible and say that again? QUOTE]

I will. Im not BSing it starts just as easy as my two stroke, hot or cold. One of the main reasons I have waited as long as I have to get a 4 stroke is I wanted them to overcome the starting issues before I was willing to purchase one. A buddy of mine had an 01 YZF426 and that darn thing was an utter pain to get going all the time regardless of hot or cold. It wasnt even worth it so I said until they figured it out I wasnt buying. I rode an 05 CRF 450 for a few weeks and I found that thing to start much better, absolutely night and day compared to the old YZF426 and that made me feel much better about it. But my KXF is excellent it has started on the first or second kick everytime and it just flat out starts as easy as any bike I have ever owned, and up till now I have only owned 2 strokes.


Posted by: biglou---------------------

I got along great starting my 01 426.


Posted by: JST122---------------------

Quote:
Originally Posted by biglou
I got along great starting my 01 426.


I dont doubt that you did, I have talked to several past owners and present owners that have said the same as you, they just said you had to get used to the routine and get it down and then it wasnt a problem. But in any event the new 450's are much easier to fire up than the old 426 with decompression lever and what not. My buddy always seemed to have problems with his and I wasnt willing to deal with that routine to get it started. With my KX 450F I just simply kick it like I do my 2 stroke.


Posted by: Okiewan---------------------

My 02 YZF250 was a hassle at times... none have them have been tough since (04, 05 crf450 and now the 06' 250)


Posted by: nephron---------------------

Quote:
I will.


Teach me, master Rich.

In all seriousness, I absolutely know it's just me. When I first got the 500, I had a time of it. Now, I can start it in 1 kick--hot or cold. And I mean 1 kick, no shat.

This 250f? I spent 20% of my riding time last night reviving it after having my head far up my ass enough to allow it to stall (can you say 'what ' torque?). I'm gettin' closer though. Still not thrilled to shat with the motor, but given everything else, I guess it's like a woman, you've got to....well.....


Posted by: Rich Rohrich---------------------

Quote:
Originally Posted by nephron
Teach me, master Rich.

In all seriousness, I absolutely know it's just me.


If it's any consulation Eric still has a tough time starting four-strokes on occasion and I never could teach him the right way to start my 98 YZ400F, even though it was a first kick starter most times for me. Two-stroke muscle memory I guess.


Getting the pilot / slow speed circuit jetting correct makes a big difference, but for most it seems that learning what to do with their right hand during starting makes the biggest difference. A lot of guys find it easier to keep their hand still by squeezing the life out of the front brake lever.


Posted by: dirt bike dave---------------------

Quote:
Originally Posted by Rich Rohrich
A lot of guys find it easier to keep their hand still by squeezing the life out of the front brake lever.


If the slightest opening of the throttle will thwart your efforts to kick start the bike, holding onto the master cylinder instead of the twist grip also works well.


Posted by: Malden---------------------

I cant speak for the kawi 450 but i am absolutely AMAZED how easy the 06 250 f starts. Hot, cold, just dumped it... etc. One local guy removed his hot start completely and to be honest i have never used it on mine either.



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