2012 Wr450 Big bore kit 480cc


10 replies to this topic
  • Menzies450

Posted November 02, 2013 - 04:59 PM

#1

has anyone done or thinking about converting their 2012+ Wr450 to the 480cc big bore kit

 

please give any opions or facts on this topic i would love to hear both sides '



  • Krannie McKranface

Posted November 02, 2013 - 05:18 PM

#2

The general facts about big bore kits:

 

Changing the motor from a 'square' bore/stroke ration to an 'over-square' ratio, to change the powerband so the torque curve begins sooner.

...but it does nothing to change the flow of Fuel/air into the head, which is the means to creating horsepower and acceleration.

 

More torque sooner in the rpm range, but not necessarily more torque overall

All power shifted down in rpms.

Less over-rev.

Less stalling.

 

BB kits change the character of the motor to mimic old-school high-reciprocating mass engines like the XR650R.

 

 

If that is what you are looking for, then they work great.

 

If you are looking to make the bike faster, have more throttle response at all rpms, more torque at all rpms, and more 'exciting' to ride, then converting the head to YZ specs is the way to go.

 

Bikes like the KTM EXC/XC-W line, which are woefully under-powered stock, benefit greatly from the BB kits.  It reduces the need for constant up/down shifting.

 

The WR, with the GYTR equipment, is reasonably potent, power wise.



  • Menzies450

Posted November 02, 2013 - 05:39 PM

#3

Thanks for the info I just wanted a bit more out of my bike maybe instead of the bb kit I should go with the wiesco piston an rings?

This is my setup on my bike

Fmf slip on
Comp ect mapped to most aggressive map
08 yfz intake cam
Fmf snap
Throttle screw removed
Engine ice in rad

Anything else I can do


  • Krannie McKranface

Posted November 02, 2013 - 08:57 PM

#4

Port your head!

 

The stock head is a joke for flow.

 

Just about any other 450 out there has a better flowing head.

 

I know it sounds like a 'big deal', but it's so very, very worth it

 

You can hear how much more robust the power is in this video.....and I'm trying to keep it under 4k rpms because it is so damn silppery....

 

http://www.youtube.c...eature=youtu.be

 

In this one I'm try to intimidate (meh) the guy in front of me by letting him hear my motor (didn't work)

 

http://www.youtube.c...h?v=eisPcCBNv74



  • Menzies450

Posted November 02, 2013 - 09:09 PM

#5

Kran did u get the stock head polished and ported of did u buy the gytr one?

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  • JDLowrance

Posted November 02, 2013 - 09:57 PM

#6

Was that footage shot from the belly button cam?

 

You need to show me where that trail is. Looks like is covers some ground.



  • KennyMc

Posted November 02, 2013 - 11:20 PM

#7

Kran did u get the stock head polished and ported of did u buy the gytr one?


AS Racing in Canyon Country, CA did the work on the stock head. :thumbsup: Had mine done as well but not as an extensive port job. It is a nice addition to the YZ Cams.

  • Krannie McKranface

Posted November 03, 2013 - 06:40 AM

#8

Was that footage shot from the belly button cam?

 

You need to show me where that trail is. Looks like is covers some ground.

 I will show you.....but it's gonna cost you.... :smirk:


Was that footage shot from the belly button cam?

 

You need to show me where that trail is. Looks like is covers some ground.

 

It's now a 'Nipple-Cam'.......



  • MidlifeCrisisGuy

Posted November 05, 2013 - 10:56 AM

#9

Port your head!
 
The stock head is a joke for flow.
 
Just about any other 450 out there has a better flowing head.


Apparently the 2012 head is different than the pre 2012 heads.
 

The 2012 WR450f intake port looks absolutely cavernous. I'm definitely excited to test it back-to-back with the 2011 head with much smaller ports.


http://www.yfzcentra...ng-no-hvp.html 

There is another thread in that series, but I can't find it at the moment.

Krannie: what was the significance of doing the whole lap in 2nd gear ?

Edited by MidlifeCrisisGuy, November 05, 2013 - 10:57 AM.


  • MidlifeCrisisGuy

Posted November 05, 2013 - 11:05 AM

#10

Found it.
http://www.yfzcentra...birt-style.html

  • Krannie McKranface

Posted November 05, 2013 - 05:07 PM

#11

Apparently the 2012 head is different than the pre 2012 heads.
 

http://www.yfzcentra...ng-no-hvp.html 

There is another thread in that series, but I can't find it at the moment.

Krannie: what was the significance of doing the whole lap in 2nd gear ?

 

Yes, the 2012 head is like an '09 YZ head, but not exactly.

 

Robert was on a KTM geared 15/45. He was reluctant to ride this trail because it is tight. He had been stalling on the hills all day.

I promised to ride in no lower than second gear, to match his first gear, to show him it was no big deal. Much easier than the stuff we were doing earlier that day.

I liked doing it in second gear.....it gave the trail another level of difficulty...






 
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