I have a question for you tech guys. I've heard two different things.

1. The YFZ cam when turned to do the cam mod is the same as the YZ dirt bike cam with the timing marks lined up.

2. I've heard that even with the YFZ cam mod the cams are still different and the YZ dirt bike cam yields more power.

Which one is the truth? Does anyone know any cam specs to back up either claim?

Thanx, Diggler

 

They are the EXACT cam, this has been confirmed 110%....The YZ bike has more power because it still has 10CC's more. Check out y f z c e n t r a l . com for info, take out the spaces though.

 

whitey, I also heard that cutting the grey wire on the cpu box connector advances the factory retarded timing on the 450, Have you heard the same bro? Late, NiK

 

<FONT face=Verdana size=1>whiteyfz450,

I believe you that they are the same but I've heard from a couple of guys over at the site you mentioned that really know their stuff and say they are not the same. The dirt bike has 12.5 : 1 compression compared to the quads 11.9 : 1 compression along with a higher rev limit and maybe a different ignition curve. 10 cc's doesn't buy you much if anything at all. Thanks for the replies guys.

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on the contrary, 10cc's buys you ALOT if its put towards stroke not bore. Hence the .6 more compression on the bike.

-Nick

 

from what I've read it's destroked 1mm and the piston is a lower compression piston. If you wanted to make it like the dirt bike you would have to buy the dirt bike crank and piston. The extra 1mm of bore is what makes it a 440 instead of a 450 to meat the rules at the time of Yamaha's R&D. I'll beat if you took equal engines (bore, stroke, compression, etc, etc) and increased one by 10cc's you couldn't tell the difference.