need an expert yfz's response....dyno'd
 

my friend has a modded yfz..real nice...just had it dyno'ed and it only came in at 39hp...can this be right or is the set up wrong...here is his list of mods


full yosh comp exhaust
cdi box
cam mod
rear carb air splitter
K & N filter

thanks guys..i feel he should be gettting more

need an expert yfz's response....dyno'd
 

was it jetted correctly? other than that the dyno was prolly a little on the conservative side, but i'd say it wouldnt be pushing more then 40-44 hp with those mods

need an expert yfz's response....dyno'd
 

thats what i thought......any idea what it is stock?

need an expert yfz's response....dyno'd
 

Yamaha paperwork mine came with said 38HP stock. I to think that dyno is probably conservative. With those mods he should be getting 7, maybe closer to 10 HP over stock.

need an expert yfz's response....dyno'd
 

What kind of CDI box did he get, some of the aftermarket cdi's actually produce less rwhp on the dyno. Plug in the stock one and see where thats get him....

need an expert yfz's response....dyno'd
 

I just happened to think, was he running knobbies on the dyno? Thaty could account for the low numbers also.

need an expert yfz's response....dyno'd
 

razr'2 is what he had on with dyno....

could the tire size...20-22 make a difference

need an expert yfz's response....dyno'd
 

Well, the knobbies won't read as high as slicks, and I would guess Razr2's might be one of the worst since they have large, widely spaced knobbies.

need an expert yfz's response....dyno'd
 

Also don't forget most manufacturer's hp specs are bhp and rwhp....figure about anywhere of a 10-20% hp loss goin from the crank to the wheels.

need an expert yfz's response....dyno'd
 

yeah so if yamaha say 38 hp thats at the crank, so about 33 to the wheels, + 6 hp gain with the pipe and filter sounds about right