07 ported head

I just finished a yzf head with a new valve lay out that i have wanted to try for a couple of years .if were going to make 64 hp this should be the head to do it the flow numbers @ 28"h20 are incredible for a 5 valve head as they usallyflow very well @ the lower lifts and then flatten out

.050" 56.9

.100 113.5

.150 165.3

.200 208.8

.250 240.3

.300 251.2

.350 257.6

.400 262.4

my curent honda heads are near 290 cfm but they dont have the flow@ the lower lifts like this head it only took 262 cfm on a honda to make 63 hp i have made 67 hp with the hondas.

Would this be different from an 06 head or are they basically the same? BTW - 67 hp is too much! :applause:

BTW - 67 hp is too much! :applause:

I believe his bikes do circles on the weekends...:applause:

I believe his bikes do circles on the weekends...:applause:

Maybe I'll send my head to Ron and beat the crap outta the 600's at the drags! :applause:

I wish there was a good 1/2 mile (or even a 3/8) somewhere around my 'hood. I've ridden stuff including 70 hp Norton twins at Ascot Park, and some Speedway, and the idea of having a 65 hp ride that weighs 220 instead of 280 sounds like fun to me.

Keep us posted on how this project shakes out. :applause:

I can just imagine what that roost will look and feel like being behind a 67hp 07.....:applause:

I am sure knobbies do not last to long either....:applause:

I can just imagine what that roost will look and feel like being behind a 67hp 07.....:applause:

I am sure knobbies do not last to long either....:lol:

Ever ride behind a CR500?

Don't. :applause:

how much $

290 cfm is a lot. An aftermarket small block chevy head with 200+cc runners has a hard time flowing that amount (unported) Nice work man.

290 cfm is a lot. An aftermarket small block chevy head with 200+cc runners has a hard time flowing that amount (unported) Nice work man.

You should see some of my HD heads 2.200" valve with over 390 cfm @ 28" h20 the yamaha was tested today it got kind just put together because of time limitation the cams qwere checked but left where they were not conclsive to hp and the steel valves with dishes in them gave up some ccs along with the piston being cut for the larger valves neteing less than 12-1 compresion but the bike still manged 60 hp @9000 rpm and maintaned 59 or better @ 11000 rpm with some compresion and better fuel it will match my best hondas before long right now it should be the fastest yamaha on the grand national circut if not one of the fastest bikes period were excited to see a diferent color the next 2 weeks are going to be exciting in florida .

You should see some of my HD heads 2.200" valve with over 390 cfm @ 28" h20 the yamaha was tested today it got kind just put together because of time limitation the cams qwere checked but left where they were not conclsive to hp and the steel valves with dishes in them gave up some ccs along with the piston being cut for the larger valves neteing less than 12-1 compresion but the bike still manged 60 hp @9000 rpm and maintaned 59 or better @ 11000 rpm with some compresion and better fuel it will match my best hondas before long right now it should be the fastest yamaha on the grand national circut if not one of the fastest bikes period were excited to see a diferent color the next 2 weeks are going to be exciting in florida .

Nice work man, its really hard to fathom that a 450cc engines really needs to flow that amount of air. The more air the better though, as long as you keep up the port velocity. Those HD heads sound like they flow some serious air. The highest flowing SBC (small block chevy) heads i've seen were something like 430cfm at .800". It was a naturally aspirated 355ci that put out over 1000hp. Flow benches are fun. :applause:

vvelocity measurerments @ the port entry are usally kept around 325-350 @ 28 " h20 where you have to be carfull is with the velocitys over the apex ssr if they get over 400 fps they quit making hp thats the reason down draft ports work so well you canhave higher overall port veloctys with no shearing because of a tight bend .

Are you talking about wheel HP?

Are you talking about wheel HP?

Yes, he is.

Yes i am talking rwh. im also getting ready to build a new head for some pepole in Italy for a rider that thinks he can win the super moto world chapionship on a yamaha with 60 + hp

my yamaha dealer did make a 60+ hp yfz and the problem was not to get there but the reability, the engine is just not suspose to take that much hp

but was it stock displacement?

what RHC talking about is a stock bore and stroke motor.

What is the strongest bottom end you can build on the YZ450F ? brands and models of the Rod, crank and bearings.

my yamaha dealer did make a 60+ hp yfz and the problem was not to get there but the reability, the engine is just not suspose to take that much hp

We actually built a 60 hp yzf 450 a few years back there was no reliability problems as a 450 its just that this new engine is showing promise of making even more power its curently less than 12-1 compresion the cams are not degreed properly it just sort got put together to make it to datona .

RHC

Are you doing any work on the YZ 250f? If so, what kind of performance gains?

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