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minty0_10

wr 450 head v yzf 450 head

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Sump plug fell out of my bike the other day witch lead to me losing all the oil and as a result the cam has marked the head. :cry:

Anyone know if a 09 yzf head is the same as a 07 wr 450?

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Are the cams the same?

Cams are not the same. The YZ cams have considerably more lift/duration and are timed differently. Not sure about valve sizes but I think they are the same.

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isn't 09 YZF the first year of the reverse engine - I thought the head was different

edit: my mistake, 2010 is the first year of the reverse engine, so 2009 YZF is basically same as WRF engine, except as stated above regarding cams and AIS

If the YZF head comes with cams try them and see if you like he extra hit they give. You can always swap back to your WR cams from your old head

Edited by GuyGraham

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the yz cams make the bike run like it should. Like your 450 blew its nose. Intakes are the same.Only the exhaust is different. When you are talking about the YZF you mean the bike not the quad right?

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the yz cams make the bike run like it should. Like your 450 blew its nose. Intakes are the same.Only the exhaust is different. When you are talking about the YZF you mean the bike not the quad right?

Not quite

both YZF cams have more lift

on 2007 & on WR's, the lift was reduced by Yamaha to give more low end grunt

YZF

Intake Lift = 8.65

Ex lift = 8.43

WR

In lift = 7.65

Ex lift = 7.75

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I did not know that Guy Graham . Now I do. I dont know why Yamaha detuned the WR so much. The more I freed up the power on my 04 , the better the bike handled because it felt lighter and could wheelie over things instead of crashing into them.

Its not like the YZ450 is an uncontrollable beast

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I had a 04 wr450 before i bought the 07 model i have now, Have to say the 07 model does seem to have noticeable more bottom end grunt over the 04 bike.

But if fitting yzf cams will alter the power to more top end maybe i should stick with the wr cams.

I don't ride the bike hard and spend most of the time short shifting. So its never working hard in the upper rev range.

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I put an 06 YZ exhaust cam in my 08 450 and the bike makes more power everywhere.

If memory serves me correct when I measured the YZ cam had more lift.

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I had a 04 wr450 before i bought the 07 model i have now, Have to say the 07 model does seem to have noticeable more bottom end grunt over the 04 bike.

But if fitting yzf cams will alter the power to more top end maybe i should stick with the wr cams.

I don't ride the bike hard and spend most of the time short shifting. So its never working hard in the upper rev range.

exactly why they did it

MX'ers need top end power, we need low down controllable grunt

I thought about swapping to YZF cams, but then I thought about it and how much time I am actually on the stop and then I realized that I have more than enough power for what I use the bike for

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