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Discussion Starter · #1 ·
Well I swapped my cams today
Set up before and after
14 stock cams
13.1 wiseco piston
Hvp ported head
Fuel controller
I run with the lid on box but I have a ers vent in lid with pre filter like a 4x4 inch opening
Fmf exhaust 4.1 rct factory pipe
Only change was 06 intake cam and I had to add a few % more fuel in a couple spots
I did have to re shim my valves had 180 all the way across and went to 170 all the way across had .009 clearance on 2 and .010 on 1 so was close enuff for me
What a diffrence this made
Pulls harder from idle to a never ending top end

Yes it pulls harder on the bottom and midrange
But it is crazy on the top end feels like you will never reach the rev limiter it just keeps on pulling and pulling and pulling
This is the best single mod I have done it made more diffrence than porting and piston combined
 

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Wher and what did you pay for the cam? Getting my valves checked next week and was thinking of having this done.
 

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Discussion Starter · #5 ·
I got my cam off eBay used for 55$
I think the diffrence would have been felt without my outher work being done it's that much of a diffrence
I feel like I picked up 2/3 hp from bottom to 3/4 throttle and picked up 4/5 hp 3/4 to wide open
I'd say the gain would be the same on a stock motor
I had a fully built Chris Williams ltr before this with plus 1mm valves web cams etc etc and it's no comparison to this yfz
 

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Discussion Starter · #8 ·
54 hp 33 tq
My ltr made more peak power but the yfz makes more across the board
I know some dynos read high or low and its only a tool for tuning but the but dyno tells me the cam swap was the single best improvement I done after the big 3
 

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54 hp 33 tq
My ltr made more peak power but the yfz makes more across the board
I know some dynos read high or low and its only a tool for tuning but the but dyno tells me the cam swap was the single best improvement I done after the big 3
That's good , im looking to get my head ported already !
 

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54 hp 33 tq
My ltr made more peak power but the yfz makes more across the board
I know some dynos read high or low and its only a tool for tuning but the but dyno tells me the cam swap was the single best improvement I done after the big 3
Where did you Dyno at? Did you post your dyno graph in the dyno section?
 

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The difference is a combination, the cams alone do help, porting and polishing are not very noticeable on the R's without a piston and with that you need a cam.

Stock R cams suck
 

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The fuel injected model intake can is better suited to a lawn tractor... Yamaha put a low duration cam in to prevent torque loss from reversion in the big slow badly shaped intake port on the fi setup.... Putting in more cam duration without speeding up intake velocity would have a very negative affect on bottom end and response
 

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Discussion Starter · #15 ·
Without head work u may loose bottom end I'm not sure
I'd say if u bumped compression at same time u would not I know the combo as a whole runs awesome I didn't loose anything on the bottom actually gained some and I already had all the outher work done I just swapped cams
 
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