Mixxer will you please post a picture of your port?

they have some pics of the YFZ head on their website.

here are some pics of my head that mixxer did.. it is a +1 head.. he sure does some really nice work. on my honda i had 3 differant ported heads.. mixxers head made way more power then the other 2.. mixxer did my kids banshee to.. and that thing flat rocks

thanks guys....

i'm not really sure who thinks they could gain much info from a 2D picture of a 3D object...especially one as involved and convoluted as port layout....

volumes.. taper angles... bowl to valve diameter...seat angle progression...are just the tip of the iceberg on porting...all measured and laid out based on lots of other engine components and intended engine use....

the pics may look pretty... but you wont really know anything about the things that really make a port job effective....

im not looking to gain any info from your pictures.. i was just curious to see what the venom port looked like, ive heard nothin but good things and was curious

here is a pic of mine...hehehehe

i'll put up some decent pics soon ......

but every time that happens you will get the "attack of the know-it -alls"

who , of course, have never ported anything...and don't really know any of the physics of port flow....but will chime in to tell you they know everything froma 2d picture...AND how much better their porting was done, since the only science involved is making every port as big as possible..... sad but true, happens most of the time......

dont you just love the know it alls??? haha

i have 3yfz customer's heads on deck for this week... i should be able to get some decent pics

Thank you i really appriciate it

I want to comment about a guy this past sat day who asked me and my riding group about how and what all can be done to the yfz to make it fast. I laughed some, as I did not know quite where to start, so I asked.... "what all have you done to yours now?" He replied.... "Pipe, Uni, and an "BIG EXTREME" port and polish".... so I said well sounds like that is all that you need done. Then some one else asked him (since we have a dealership named Extreme)..... do you mean the dealership ported your head?..... he replied no it is a EXTREME port and polish... as in real big.

Yeah needless to say he was not fast, and at best I hope he still has the same factory hp/tq as he did before his major, super duper, larger then life port and polish.

some of you should look up motoman's website.... it is good for thought provoking on the topic of porting.....


correct porting has nothing to do with something as simple as hogging out the ports 'till you see through the walls...

correct porting is what gets the most cfm while maintaining the highest port velocity.... velocity provides the inertia need to keep filling the cylinder after the piston has reached the bottom of the stroke ... the cam still holds the intakes open well past BDC....and since the piston not creating any more vacuum...and infact is now on its way back up... intake port velocity is the only way the cylinder will continue to fill instead of causing reversion.....

the best ports will also require the smallest jet sizes since they give the strongest vacuum signal to the carb ... a stronger vacuum will pull more fuel through the same size jet.....

and lastly.... if 2 porting arrangements provide the same peak HP...the one with the highest port velocity will have the widest powerband and best throttle response...

stuff to think about

HaHa so what you are saying is that my 160 main jet, 42mm carb 534cc is motor is not bad?

PS. even at around 15.3 compression it held up great with a 15hp shot of nitrous this past weekend

i've noticed that when people do mods the automatically think they need to go bigger in jets sizes.. not always the case. look at that 160main on terse 534cc has thats low as hell and i'd put money on it runs pefect!!!

right guys....

if you make 55hp...it takes a specific amount of burned fuel to make that pressure....

if one 55hp machine needs a 210 main to get that amount of fuel, it is because there isn't as much vacuum signal at the carb as there would be with a 55hp machine that needs a 155 main jet...

they both burn the same amount of fuel to make the same amount of power.... but the one with the weaker vacuum signal needs a larger aperture (hole) to get enough fuel through with the lesser vacuum signal....

same as a straw that doesn't change diameter... a stronger suction will pull more milk through the same size hole.....

the hole is only part of the determinant of how much liquid gets passed through.... the other part is how much vacuum is acting on that orifice......;)

So what you are saying is that there is a difference between a $2 hooker and a $200 hooker?

Just messing around. Good info John.

there is no difference!! they are both hookers

lol.... maybe i should change the word "milk" to "whiskey"

I have just done my first rebuild on my yfz. Venom did the port and carb bore for me. Well I got it all back together and and it did not run all that great. Everybody was saying that I need to increase my jets do to all the work that had been done..
Before the build I was at a 175/48...Ran great...
After the build put in a 195 and left the 48...
Let me say the wrestling match was on....Hard to start, erratic idle,flames out the pipe,A/F screw not changing a thing. It was all over the place..I was just trying to get it close to make sure everything is ok before I go to the dyno...so I have spent the better part of the last three weeks trouble shooting this beast...You know checking the TPS, looking for air leaks just going nuts.. Well I decided to drop the pilot to a 45...Not much change..Drop it to a 42...Now that made a difference, got the idle down and able to work with the A/F screw....

I really thought something was wrong with it when I had to drop the jets from where I was because all that I have read and heard was to jet UP..... BUT it looks like I am heading in the right direction now...It is all starting to make sense...Now I just need to start on the main jet....

Thanks mixxer for sharing you knowledge with us..You where truly a live saver to me on this one..
Thanks Terse you have chimed in on all my questions and lead me in the right direction...
Blackedyfz450--- Keep scratching man you'll get there.....

what you mean your pics aren't good enough ? LOL.. these are pics of my head that you took and posted at the org.. i just robbed them from there to put here... hahahahahaha

dyno with A\FR is the very best way to nail down jetting....and the bummer is that a 4-stroke wiull still run fine while it's down 10% from it's potential Hp from incorrect jetting....

millertime...i'm sure the pics are great....i typically use the lo-fi version of the screen because i'm on dial-up service...so i usually don't see any pics that are posted... :(

How much does Venom charge to have a port and polish done?

there are package prices and individual prices....

check the website at www.venomperformance.com

hey when i copy and paste, www.venomperformance.com it takes me to a diesel truck place.. and when i google it i can not find your site john

oh got it... it is dot net.... not .com

so pretty much when i get my head and carb back from venom, im boned if i dont get it dynoed to be jetted right

its not just Venom, your going to be in the same position regardless of who does the work

yes of course, i didnt mean only because it was venom
anybody know a ballpark of how much a dyno tune session would cost? know i gotta work i finding one local

right . net

anything that anyone adds...from an intake ...to an exhaust ...SHOULD be dynoed & A\FR tuned on a dyno in the locatation\ altitude where you live....

that's the only relevant info for your machine and riding location....

any machine that has any mod that isn't tuned on adyno with afr is not getting its full power potential... that's just the way it works...

where are you located and how much?

mid michigan.......

$250 per hour for dyno tuning....minumum 1 hour....

$75 for 3 runs with no tuning..... if i touch anything other than the throttle, it jumps up to the $250 tuning rate.....

runs are just that, runs...... tuning is an entirely different deal...

the tuning price is what it is because of so many machines that have hit the dyno with so much wrong.... from jetting to cam timing to dirty filters and worn out exhaust packing.....

can't \ shouldn't tune to an improperly done setup... right?

not to metion that people like to be there for the dyno runs.... and people who are there..... always want to talk.... a lot...

so, if i'm going to stop porting or product R&D for tuning.... that's the going rate...

not holding a gun to anyone's head either....LOL....

you pay for what you get

The venom dyno was not offered before, so as soon as I have money I will be calling for an appointment. Thanks for offering it. 10-15 min. form my house sure saves on gas. Glad you are willing to offer up such a great service.

Thanks
Ryan Reed

and vice versa....

haha excactly what i meant!