kx500 power opinions

[tharden]

I have got to say I did not think this was going to happen.  I thought I had my 500 tuned to make pretty good power, but my cousin just ran by me on a 07 yz250.  He said his bike only has a pipe,wisco piston, and carb jetted.  This is what my bike has gnarly pipe, k&n airfilter, and I leaned out the carb one point on the main jet.  I just do not get it.  The 500 seems to be running great, very smooth and powerful, but I guess not as powerful as I thought.  I just do not know if my tire is spinning too much or what. I just put a new Kenda 771 on it.  It seems where ever I go I leave a trench.  One thing though, I think I am going to switch back to the stock filter.  It seems to be better than the K&N. 

[KX500freak]

thats a sad story ,but to be realistic 
an aged pretty stock k5 delivers about 58 HP

a modded fresh 250 goes up to 50 HP or more
take the riders weight and skills ,there you go

it can be true in other words i think 

[tharden]

I weigh about 30 pounds more than he does, but I do not think 30 pounds would make that much difference.  As for the engine, it does have 162 psi which I think is pretty much where it should be stock.

[KX500freak]

everything in good order ? kips working correct ?
muffler repacked ?

if so ,i can only suggest the magic hand of mr k5 stewart

[kaw rider]

gearing is very important to go fast.

[KX500freak]

gearing is very important to go fast.

yea definitely ,forgot to mention ,my dirtbike runs 15 /48 which i like for pull and topspeed

[PowerFiend]

I just picked up a KX5 today, and have to say that it accelerates a lot harder than my 07 CR250 or my tired CR500, so something is definitely wrong with yours.

...and YZ250's won't walk on either of the CR's.

[stewart]

thats sad... somethings way off..

[KTMEXC125]

could it be the gnarly pipe? my 2003 k5 seems like the power just flattens out on top. it has a gnarly pipe, stock silencer and stock gearing. it'll pull a wheelie in 1-4 and has plenty of compression (just been replated and new piston) i havent dragged raced any of my friends bikes, ive only opened it up by myself on country roads but it doesnt seem to be very fast on the top end. maybe 80 mph. so im guessing a gnarly kills top end??

[kaw rider]

Throw alot of gear at the gnarly and she will be happy.

[KX500freak]

could it be the gnarly pipe? my 2003 k5 seems like the power just flattens out on top. it has a gnarly pipe, stock silencer and stock gearing. it'll pull a wheelie in 1-4 and has plenty of compression (just been replated and new piston) i havent dragged raced any of my friends bikes, ive only opened it up by myself on country roads but it doesnt seem to be very fast on the top end. maybe 80 mph. so im guessing a gnarly kills top end??

like kawrider says ,what gearing you,r running ,
my circuit sm does rip my arms off ,and close to max rpm it needs to be shifted ,
id say ,try a 15 t instead of a 14 t,this way the bike ,s longterm breath gets alot bigger

[tharden]

This is my gearing.  14 on front and 1 tooth bigger than stock on back.  Also,  the bike has a flywheel weight.  How bad does this hurt the top end?

[Polar-Bus]

I have got to say I did not think this was going to happen.  I thought I had my 500 tuned to make pretty good power, but my cousin just ran by me on a 07 yz250.  He said his bike only has a pipe,wisco piston, and carb jetted.  This is what my bike has gnarly pipe, k&n airfilter, and I leaned out the carb one point on the main jet.  I just do not get it.  The 500 seems to be running great, very smooth and powerful, but I guess not as powerful as I thought.  I just do not know if my tire is spinning too much or what. I just put a new Kenda 771 on it.  It seems where ever I go I leave a trench.  One thing though, I think I am going to switch back to the stock filter.  It seems to be better than the K&N. 

You have something very wrong with your KX500. Traction (lack of) as you claim, should have played a negitive role with BOTH bikes as well, so unless Bubba Stewart was piloting the KX250 you raced, you "should" rip a KX250 a new a$$ in every aspect of a drag race.
There can be som many reasons your KX500 is not running 100%, we need more details.
I've raced TON'S of other bikes/atv, and pretty much sit every one of 'em down. The only true challenges come from modded 450 4 stroke when we race in loose terrain, then I sometimes get beat in a race, but not by much..

[DoldGuy]

Tharden,
The gnarley is a great Torque pipe for Bottom & Mid, it signs off a little early up top. I think  what they are saying is to gear the bike to ride the Torque Curve as your setup is not a RPM design. If you drop 4 teeth on the rear (or up 1 on the front) you will utilize the torque your motor is making & each gear will pull much longer opposed to just reving out.

[Mick]

It isn't surprising at all you got beat by a new 250.  We can stop pretending that 500s are that much faster than anything else.  The YZ250s run so good rider ability will overcome horsepower everytime.  You will never beat another rider as easily as you'd like to...if you beat them at all.  I don't know how many of you race, but it's not uncommon at all for a 250 smoker to outpull a field of 500s to the first turn.  Happened all the time on my KX, happens occasionally still on my CR.  As the distances shorten to the first turn, it becomes almost impossible to get the holeshot on a 500.  250s are always quicker out of the hole.

You said so yourself the 500 is running great.  So instead of trying to trouble shoot the bike, try leaving it alone for a change and improve your riding ability.  That will almost curtainly allow you to beat your friend in the future.

The power of a 500 is it's best friend...you should also know it's a riders worst enemy.  If you can't get all that power to hook up you're not going anywhere.  I'd rather have 56hp I could put to the ground than 65hp I couldn't.  You mentioned you run a Kenda 771 on it?  I've never used a Kenda so I don't know how good or bad they are.  But honestly my impressions are they aren't good tires.  Regardless I would be more concerned with your size selection than anything.  You say you dig a trench where ever you go?  Not good.  Sounds like your tire is too small.  100s, 110s are for mini bikes.  I use a 2.50x19" rim, 120x90 D756 and I've got a prototype TuBliss core to begin testing as well.  I don't get beat very often, and I don't suspect I'll ever get beat again with the TuBliss.  In this sport racing is little a matter of horsepower as it is traction.