48.4 bhp ???? what you think

12 replies to this topic
  • benuk

Posted March 01, 2005 - 12:25 AM


i had my yz450 on the dyno yesterday and i got 48.4 bhp at the rear wheel is this good or bad for the mods ive got >?? :) i was hoping for more :) think its about 56ish bhp engine power when you take all the drive train loss off etc

gasflowed head
bk mod
power now etc etc

full spec in my garage :p

  • rws

Posted March 01, 2005 - 06:10 AM


I'm new to this game... but I thought I'd read somewhere that the YZ-F produced 46-48 hp off the showroom floor. Not sure though.

Whatever it is... I need to find a gripper seat to keep my butt on the bike when I twist the throttle! Can't imagine more to contend with. Have fun!


Posted March 01, 2005 - 06:20 PM


i know im down 24 or so cc's but ive got a hi-comp piston, hot cams auto-decomp exhaust cam, BK carb mod, and a modified exhaust, could my hp possibly be near that?

  • Crabtree426

Posted March 01, 2005 - 07:37 PM


I have a 2000 YZ426. I was always told it had 46-47 HP. I would think the 450 has 52 or so but I'm not sure.

  • ISBB

Posted March 01, 2005 - 08:38 PM


From my experience if you slap a dirt tire on a dyno you are not going to get an accurate reading... the tire is probably slipping giving you the lesser HP reading... i had a buddy that dynoed a cr500af that had a mild port job and said he only had 40 hp when we all know that there is more than that in a cr500... after swapping for a street tire... he was really close to 60.. :) big diffrence...

  • Joe_Jet

Posted March 01, 2005 - 08:41 PM


All dynos are different. The important thing is do you feel it, and did you dyno it before the mods to read the gain?

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  • benuk

Posted March 02, 2005 - 01:00 AM


but could the stock 50ish bhp be at the engine not at the wheel :) if so ive made a 6bhp gain and i dont think thats bad :)
i can feel a real good gain when riding the bike pulls really hard from low down all the way to the top had a real job keeping in down on the dyno when runing up though the gears

  • benuk

Posted March 05, 2005 - 02:31 AM


im starting to think i should be getting more bhp than that now :)
does anyone know if the bhp claims are engine power or rwp ??????????????????????????????/

  • rebel1916

Posted March 05, 2005 - 06:45 AM


bhp claims are always, always at the crank

like the man said 2 different dynos will usually read 2 different horsepower for the same bike. its only a usefull tool if you did baseline runs and a run after mods on the same dyno you can figure out what % you improved.

once again street tire is needed

  • yzfmxer

Posted March 05, 2005 - 08:09 AM


I could be wrong, But BHP and HP are 2 different figures. That, and if you dynoed it with a dirt tire, well thats a big problem. :)

  • benuk

Posted March 06, 2005 - 06:39 AM


my bike is supermoto spec so its allways got slicks or wets on :)

  • yzfmxer

Posted March 06, 2005 - 09:05 AM


Ohh ok,

I wasnt sure about the difference of the BHP to HP difference. So I googled it and came up with this

"BHP and HP vary greatly. BHP stands for "brake horsepower" which is the horsepower as measured at the drive wheels. "HP" is what is called "net horsepower". This is the engine's horsepower rating measured at the flywheel. It will always be higher than the BHP since it takes power to move drivetrain parts. Generally you loose 10%-15% of the engine's power by the time it reaches the wheels."

So thats answers my question, But in the case that your running a street tire and now we know what the difference between BHP and HP are, I would say Yes your horse power sounds alittle low. But there are sooo many varyables.I.E. tire presure, jetting, elivation, is the elivation compensator on the dyno?, and every dyno reads different, some low some high, thats why its soo important to get a good baseline before all the mods and then after, Because you can baseline at whatever, but all that realy matters, is the horse power differnce from base line.

  • yzfmxer

Posted March 06, 2005 - 09:07 AM


Ohh, I just thought I would add why I think its alittle low.
MY CRF 450 baselines at 54 HP (at the rear wheel)

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