04,05 vs. 06,07

[PowerJunkie]

okay im looking to buying a used yfz in the late spring and im most likely getting a yfz. i know the differences between the 04 05 set up from the 06 07. but my questions is. is the 439cc engine slower then the 449cc engine? or in other words if i race mx with them would the 449cc be faster or be just about the same and rider skill would have more effect? thanks


ps i tried running a search but its kinda hard when the min. word langth is 4.

[Trx250rider86]

i would like to know this also

[250r4life]

the 06 is quite a bit faster than the 04-05...

[Toadz400]

The '06 isn't much faster than an '04/'05. The biggest difference is that it's much SMOOTHER than the early models. Because of the smoother powerband you can definately ride faster much longer. If you wanted one with the 449 I would go with the '07, as they upgraded more things and the biggest difference is the oil mod has been done. If you don't mind going with the 439 (no big power difference) I would go with the '05.

[yfz450rida]

Here my 2 cents i currently have a 05 and 07 i bought my 05 new and raced it in 05 and 06 and this coming season i will be on my 07. From my experience the 07 fells like its smother and a little more torqe, the 05 seems liked they wanted to be reved a lot higher to perform good. But the my 07 is different then my old quad if fells like it has a little more but i really think the differnce is the power dilivery. Another idea is half way through last years season i had my 05 built to 06 specs with the crank and piston to bring it to a true 450. My 07 was stock motor and(when tested in a heads up race) Both my quad are set up farely the same as for suspension and tires and rims and in a straight up drag on dirt they areback and forth, which ever gor the jump. So even when the 05 motor was stock there was little differnce. If your going to race it i would probably try to get as new as you can afford because of the fact that there have been improvements and racing is very hard on stuff. But if your racing for the first time to see if you like it i wouldn't diagree with u if you went with a older quad JUST MAKE SURE IT WAS TAKEN CARE OF!

[PowerJunkie]

thanks alot that helped alot.