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Abrupt rpm change just above idle

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(New-to-me 2009 YZ450F, FMF Powercore, WR450F header, oem pilot jet, 168 main, oem needle in 3rd pos.)

 

Just above idle, rpms shoot up suddenly when opening the throttle very slowly.  Is this common on YZ's ?  Wanting a more linear response for woods riding.

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Yes, the track bikes are very linear in throttle. Some are even 1/4 turn

You are used to non linear, slow throttle.

You  can slow down the throttle with the G2 throttle tube as mentioned, which is what I use on all my track bikes so you can meter out throttle for sketchy terrain.

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Stalling can be from a too low an idle speed or the need for more flywheel effect if trail ridden. Keep in mind, you have a race MX bike and once started, is not designed to be below 5K rpms until the race is over.

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(New-to-me 2009 YZ450F, FMF Powercore, WR450F header, oem pilot jet, 168 main, oem needle in 3rd pos.)

 

Just above idle, rpms shoot up suddenly when opening the throttle very slowly.  Is this common on YZ's ?  Wanting a more linear response for woods riding.

 

Adjust your tps: you must use a regulated 5v source for this.

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Stalling can be from a too low an idle speed or the need for more flywheel effect if trail ridden. Keep in mind, you have a race MX bike and once started, is not designed to be below 5K rpms until the race is over.

So, what can I do to make it run more like a WR450?  I have a gytr heavy flywheel weight installed.  Will be getting the G2 throtlle and checking the tps.

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Try to source WR cams

Install a WR Muffler.

 

 

Many guys have similar issues. They 'think' they need a 450 MX race bike and in reality, a 250 is plenty and often, a regular trail bike (TTR/XR/DRZ) is plenty. I ride a wr250F off road and it is really too high strung for the type of riding I do these days. I love it but I rarely can let it run like it was designed too. I am not a racer anymore.

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