2007 YZ450F Jetting with stock exhaust


2 replies to this topic
  • Dnnap

Posted July 06, 2009 - 05:43 AM

#1

I just got a 2007 YZ450F with some engine mods, but the guy I bought it from sold it to me with the stock exhaust as opposed to the DRD he was running.
The bike has NO bottom to mid pull, so my question is would this stock exhaust be the culprit to the power loss and if I go to a DRD would this solve the problem?

The engine mods are as follows:
-Modified Head - ported and polished
-Web cams
-Carb work by Tokyo Mods
-New HC piston and rings

Carb settings:
main jet - 165 was running a 170 with DRD before I bought it.
clip position = center position
Fuel/air screw = 2 1/4 turns out

Any help or advice would be greatly appreciated.

Visit the ThumperTalk Store for the lowest prices on motorcycle / ATV parts and accessories - Guaranteed
  • grayracer513

Posted July 06, 2009 - 08:26 AM

#2

The pipe may not be helping you, but it isn't hurting that much, either. The cams are likely the problem. If you switch to a stock set, especially one for an '06, your low/mid power should improve.

You may want to verify that the cams are timed correctly, too.

  • Dnnap

Posted July 06, 2009 - 03:14 PM

#3

Thanks for your help.
Well I checked the cam timing and the markings are as per the manual at TDC. The exhaust markings at 9 and 12 o'clock and the intake at 12 and 3 o'clock.
I also checked the valves while I was there and all are in spec.

I'm new to the 450's so I'm gauging the low to mid range on my '07 YZ450F to my friends '09 YZ450F all stock, and the '09 has much more pull in the mid range, while my '07 feels like it has no mid and revs out very quick.
I'm not sure what to try first.





Related Content

Forums
Photo

BIGBORE FOR YZ450F 2006? by Taattie94


Dirt Bike   Make / Model Specific   Yamaha   YZ 400/426/450
  • 3 replies
Forums
Photo

James Stewart back on a YZ450F by YamaLink


Dirt Bike   Special Interest Forums   Pro Racing
  • Hot  47 replies
Reviews

Yamaha YZ450F 2017 by Chris.GVS


Yamaha YZ450F 2017
  • * * * * *
  • 1 review
  • Last review by Tommyk_55
  • On January 15, 2017
Forums
Photo

Snake pit oct 30th by The Anvil


Dirt Bike   Dirt Bike Regional Discussion   California
  • Hot  293 replies
Forums
Photo
Supercross

Wilson the Blue Privateer by jetfuel


Dirt Bike   Special Interest Forums   Pro Racing
  • Hot  50 replies
 
x

Join Our Community!

Even if you don't want to post, registered members get access to tools that make finding & following the good stuff easier.

If you enjoyed reading about "" here in the ThumperTalk archive, you'll LOVE our community. Come join ThumperTalk today!

The views and opinions expressed on this page are strictly those of the author, and have not been reviewed or approved by ThumperTalk.