ALL OF THE FOLLOWING WAS DONE ON PAVEMENT! PUT THEM IN THE DUNES AND EVERYTHING CHANGES!!:
I have a new 2000 K5 (left over) and have run MANY times against my buddies 03 CRF. With me running my 13/47 trail gearing and him running his stock gearing we run dead even thru the gears - I kill him when he runs out of gears though! I have never tried the 15 up front. My bike is bone stock as is his!
Another friend has a 02 CR250, PC pipe, rad valve, trimed head. The 5 cleans him up - not twice as fast but a good steady pull away. Funny about the 450 - it was made to run against the 250's - its WAY more powerful!!
Now heres the way I look at the whole situation. Like it or not the 5 is old tech. The CRF is as up to date as POSSIBLE! The CRF (great bike) is at its limit and ANY mod work will show up in reliability - it is at the top of its latter for most "normal" folk. The 5 on the other hand is, well to say the least, at the bottom of its latter and can be improved MAJORly with fairly inexpensive mods - with little to nothing in reliabilty issues!
Here are some other issues comparing the bikes:
The CRF gets AWESOME gas mileage - 2x that of the 5!
The 5 can run for WEEKS without worrying about oil loss, the CRF is limited to miles (my buddy has to carry crankcase oill when we go trailriding and his is BRAND NEW!)
The 5 BY FAR out torques the CRF. Run the race in the sand and you will see!
The CRF is easier to control a wheelie on - I DIDNT SAY TO GET IT TO WHEELIE! That thing could make a wheelie king out of a child! The 5 will kill you if you dont respect it!
I like the 5 better in the woods but the 02 CRF's cornered better then anything I have ridden in a LONG time!
Parts costs - well, lets just say the CRF is for the wealthy and the K5 for EVERYONE/ANYONE who wants one of the most AWESOME bikes ever built!
I ride my k5 everywhere (it is street legal) and have NO problem drawing in anything I have run across from corner to corner in the woods! It ROCKS!! Sand - it rules! Hills - HAHAHAHAHA! HUGE SAND HILLS HAHAHAHA! Trials type riding - 1st gear just above idle and it is unstopable (trials riding is the CRF's downfall unless they are revloc equipped!). Log jumping/stump pulling done with respect (throttle control) - NOTHING LIKE IT!
WHEELIE ANYTIME ANYWHERE - MAN I LOVE POWER!!
I rode CR500's for years and got BONE tired of their starting issues - changed to green and GLAD I DID!
Just my 2 cents!
Woodsy