'04 YZ250 Vs. '05 YZ250

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maddog1927

Member

Dec 25, 2005

2

0

• Feb 19, 2006

• #1

So what changed with the motor from '04 to '05 on the YZ250? Bore and stroke seem to be the same. It the porting different? Or something else? My buddies stock '06 has tremidous power. I am trying to figure out why.

 

oldfrt613

Feeble Sponsoring Member

Member

Jun 29, 2005

443

0

• Feb 20, 2006

• #2

It's my understanding that the motor is basically unchanged. The changes are in the chassis. Both ours run about the same, but we have done some jetting ( pilot change if I recall ). The new one is lighter and "feels" crisper.

 

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DLHamblin

Member

May 27, 2005

268

0

• Feb 21, 2006

• #3

maddog1927 said:

So what changed with the motor from '04 to '05 on the YZ250? Bore and stroke seem to be the same. It the porting different? Or something else? My buddies stock '06 has tremidous power. I am trying to figure out why.

Click to expand...

How many hours on your top-end? His '06 just may be "fresher".

 

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Dino Y

Member

Sep 17, 2003

64

0

• Feb 21, 2006

• #4

Yamaha has the same engine unchanged for 4 years. After all it's a very good engine.

 

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Matt Fisher

Member

Apr 17, 2002

136

0

• Feb 23, 2006

• #5

The pipe did change halfway through the 05 year, and is an improvement.