Machining the YZF450 flywheel


5 replies to this topic
  • Polar_Bus

Posted September 03, 2009 - 02:52 AM

#1

I have an '07 450, and after piloting both an '06 and an 08 I seem to think my 07 has somewhat of a more relaxed midrange power delivery. I was wondering... (and this might go nowhere) about machining some weight off the flywheel to free up some rotating mass... anyone ever tried this? Any thoughts? Thanks!

PS... NO I don't wan't to add a pipe !!!!!!!!!!!

  • KtmKramer

Posted September 03, 2009 - 04:55 AM

#2

I've never done it, but I know guys that have. It makes the bike rev faster, hit harder, but it also doesn't chug as well, and it's easier to stall.

  • grayracer513

Posted September 03, 2009 - 07:55 AM

#3

The flywheel is already smaller than your gas cap. It also has a lug on the outside that A) can't be removed because it triggers the ignition, and :ride: requires the slot you will see machined in the back side to restore balance. There is minimal material there as it stands, and IMO, removing almost anything from it would introduce the risk of having it blow apart at high RPM, which could be personally disastrous.

In any case, there isn't enough there to remove that it would have the desired effect.

If you want more mid-range, drop an '06 exhaust cam in it and start there. The cams are most of the difference between the two engines, and interestingly, a heavier flywheel may actually improve your low-mid output.

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

Posted September 03, 2009 - 08:21 AM

#4

The flywheel is already smaller than your gas cap. It also has a lug on the outside that A) can't be removed because it triggers the ignition, and :ride: requires the slot you will see machined in the back side to restore balance. There is minimal material there as it stands, and IMO, removing almost anything from it would introduce the risk of having it blow apart at high RPM, which could be personally disastrous.

In any case, there isn't enough there to remove that it would have the desired effect.

If you want more mid-range, drop an '06 exhaust cam in it and start there. The cams are most of the difference between the two engines, and interestingly, a heavier flywheel may actually improve your low-mid output.


Thanks,
I didn't know Yam mellowed out the exhaust cam in '07, I actually thought they (Yamaha) maybe put a heavier flywheel in my '07, I will definatley look into that.....

I was initially very happy with the relaxed power of my '07, as it made for an easier learning curve getting used to the bike in generall, but now that I am more comfortable on the chassis, I would like some more snap in the middle.

  • grayracer513

Posted September 03, 2009 - 12:23 PM

#5

They didn't mellow it out, they narrowed the lobe centering for more top end, and gained around 1 HP at peak by doing so. The penalty for that is a loss in the low end, though. You may also find that a Vortex ignition, or the box from an '06 could make a difference, as well.

  • ww44wrf450f

Posted November 14, 2009 - 05:29 PM

#6

so did you buy a bike????





Related Content

Forums
Photo

100 hrs on 2014 yz450f, shim valves or replace them? by ttr230rider6


Dirt Bike   Make / Model Specific   Yamaha   YZ 400/426/450
  • Hot  79 replies
Forums
Photo
Motocross

Thinking about Yamaha 250... by Arctic Pride


Dirt Bike   Special Interest Forums   Pro Racing
  • Hot  491 replies
Forums
Photo

yz250x vs 450 4t comparisons (preferably desert riding) needed by JakeNorthrupYZ450F


Dirt Bike   Make / Model Specific   Yamaha   Yamaha 2-Stroke
  • 9 replies
Forums
Photo

Snake pit oct 30th by The Anvil


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

YZ450F 03 Sparks driving me crazy by SirAttard


Dirt Bike   Make / Model Specific   Yamaha   YZ 400/426/450
  • 5 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.