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Discussion Starter · #1 ·
I talked to Lenard at Duncan Racing and he says not to do the cam mod on this engine. Says its not worth it and that if it runs better with it modded thats how yamaha would have built it. I did some searching and it seems like a lot of guys on here have done this to there bike. Just wanna get some opinions on this, I will be doing mostly mx now and still some desert riding. What are the known problems that occur when this is done, if there is any. It seems to me like good theory on why you would do this, but when a guy that has the race expeince of building motors that are proven tells me not to do it, it raises an eyebrow, ya know?


Thanks in advance, Chris
 

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yfz without cam mod= more controled power.. even power throughout rpm
yfz with cam mod= more abrupt power.. slight loss low end.. great gain up high...

do it
 

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The only reason I can see why Duncan would say not to do it is because it's a hell of a lot harder to ride after that. It changes the way the quad pulls, response to throttle, and torqe of the motor. Once you get used to it, it's all advantage though. I had a hard time getting adjusted to the throttle response and extra snappyness of the motor and over jumped almost everything the first couple races but I pulled the holeshot every moto with ease and after a weekend of racing I was well adjusted and I can honestly and truthfully say that the cam mod is a great advantage over stock when you get used to it.
 

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QUOTE (Unlukky @ Mar 2 2009, 12:08 PM) index.php?act=findpost&pid=752883
The only reason I can see why Duncan would say not to do it is because it's a hell of a lot harder to ride after that. It changes the way the quad pulls, response to throttle, and torqe of the motor. Once you get used to it all advantage though. I had a hard time getting adjusted to the throttle response and extra snappyness of the motor and over jumped almost everything the first couple races but I pulled the holeshot every moto with ease and after a weekend of racing I was well adjusted and I can say honestly and truthfully say that the cam mod is a great advantage over stock when you get used to it.[/b]
LOL took me all of 20 min 2 figure it out, wheelie'd the whole block!!!
bro i love the cam mod!!! it free HP!!!!
and the best part is if u dont like it u can always change it back 2 stock!!!
u have nothing 2 loose but an hour or 2 for free power
 

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i disagree with the "if it ran better, yamaha would do it stock" they dont put higher compression pistons, bigger bores, port and polish, better cams.

changing the cam is just setting it to the yz timing, they are the same cam, the sprocket is just pressed on at a different angle, who knows why yamaha decided to do that, probably liability and ease of riding issues.

there is nothing wrong with changing the cams timing, except some report it has a tough time starting afterwards because you change the auto decomp too.

the cam mod is just like buying a set of after market cams for the quad, but your just changing one cam, and not as drastically as the after market companies build.

go for it!
 

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Quads have to be de-tuned from the factory due to certain unverified reasons. Ever wonder why a new YFZ doesnt have that pretty polished nice sounding exhaust that the YZF dirtbike has? Because the quads have to be de-tuned and corked up.
 

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yea they have to meet strict california rules or they cant sell them.

I have had the cam mod done for a while now and i think its a gift from god! lol free HP??!!! you gotta be a retard not to take it??!!! lol but i dont beleive the loss in bottom end, i didnt notice a loss at all, i'd say i gained power thru the whole RPM range. I hace read on here one guy that torqued his cam tower to much and caused the cam to flake somehow and chips got into his crankcase and welded to his crank bearing. Awesome mod in my opinion.
 

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Discussion Starter · #11 ·
Right on guys, appreciate the comments, although i dont think its fair to say you are a retard to not do the cam mod, haha j/k. Im thinking about doing it tomorrow while omf straitens my wheels and adds reinforcing rings to the inside. I wasnt saying im not gonna do it, just wanted to get the general opinion. Thanks again.


Chris
 
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