so far i have over 170 rev limit hitting dyno runs on my yfz since its first incarnation as a pump gas 439cc setup....and i haven't even ridden it on anything except the dyno rollers yet....and since riding in michigan sux right now... i probably wont ride it anywhere else in this configuration either..... :(

last night i had a chance to test the Ron Woods billet cam offerings for free because of my good friend Mr. Kammon Gray of KBR..... KBR is a Woods dealer and Kam sent me a pair to test with...many thanks!... it may take a while to get them back to you, Kam, i haven't quite made up my mind yet...lol...

now...as you remember....i had gotten a smokin' deal...as always...from Paul @ Woodward Specialties... on a Hot Cam intake cam only .... Hot Cams makes the set of intake and exhaust cams.... but since the intake cam makes the biggest difference in an engine's output.... AND i really want to see how far i can get with the stock cams anyways.... i only bought the Hot Cams intake cam, and not the exhaust cam that goes with it....

from the previous post, you will remember (especially since i'm reminding you..lol) that the Hot Cam didn't match the stock cams power until around 7500 rpm....and didn't pull away to any advantage until about 8600 rpm...at which point it went on to make approx 2hp more up to the rev limiter......

we had:
stock cams @ 53.58 hp\ 32.52 tq
hot cams int @ 55.44 hp\ 32.12 tq
and now:
woods cams @ 56.60 hp\ 31.97 tq

the woods cam set made a very similar power curve to the hot cam intake cam....but they did have a slight advantage over a slightly wider range of rpm's...and the stock cams still ruled the band until you were above 8200 rpm....


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Woods cam set Vs Hot Cams intake ....only the dyno knows...lol:

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Stock Cams VS Woods Cams:

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Stock Cams Vs Hot Cams intake cam:

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i looked up some of the testing that carb boring master, Sredrum\ Christopher, did this last summer on his YFZ480.....

sorry the runs are in MPH instead of RPM.... the tach pickup wasn't getting along with Chris's ignition that day....

again...the stock cams made the most early power...and still made very respectable top end power too...

the Crower's all had a worse powerband coupled with less peak power than the stock cams...same as it ever was....too bad nobody ever selling this stuff ever actually tests it.... an even bigger shame is that you have to sacrifice you stock cam to get one of these..... so you have a cam that runs worse...AND you lost your stocker that ran better...along with some $$$ to do it.... ouch!!

the Webs made less power early on....similar to all the cams so far...and then went on to make a higher peak near the end of the band..... BUT...i know for a fact that these are some VERY dangerous cams to run.... broken \ work hardened valvesprings are the norm...and quite a few people have lost their whole engines to this fact....



Red = stock cams........... 57.13hp
Blue= Crower Gen 2 .......55.90hp
Green= Crower Gen 3......56.79hp
Dark Blue= Web +2.5's....58.71hp

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more clearly... stock cams (RED) Vs web +2.5's (BLUE):

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most of you know this machine is planned to be a 501cc long rod stroker with a custom 98mm Venom Stroker piston made to go with the WR crank stroked 3mm.....

i really hadn't planned on doing so much testing on it as a pump gas 439cc setup.....

but... i think there is one more thing i have to try before it goes to the 501 configuration.....

i'm going to send the cylinder to U.S. Chrome and have it punched out to one of the Venom 98mm 14.25:1 pistons..... and try this combo as a high compression Big Bore just for kicks.....

98mm makes the 04-05 439cc machines into 470's.... and it makes the 06 on up machines into 480's....

on another note....does anyone know of a pro TT racer who campaigns on a yfz??

....adding a WR crank to get this setup to a true 450...and jumping from 12.25:1 to 14:1 compression would make for an extremely competitive TT mount for a yamaha rider......

have to say it, i really like how that Woods cam looks on your graph. there's that little dip in the 5500 range but it'd be interesting to see how that cam feels on dirt; i bet I'd like it better..... what could you do to help bring that dip back up with the woods, possible intake tuning?

that dip is there in different degrees no matter which cam you are running... it is least pronounced with the stock cams though..... so i think it has to be exhaust\intake tract reversion related...and the stock cams allow less time for the reversion to happen via their shorter duration... just a guess... but most of the powerband dips in that rpm band are a problem of reversion during cam overlap phasing.... more duration of bigger cams generally makes for more overlap, and exacerbates the problem....

i'll see what i can do to get rid of it...still got a few tricks in the bag

the dip is in Sredrum's 480 setup too....

man on the local level there are still tons of them, but its weird, the better the class gets the less there are... here is a thread.... food for thought...... but this Nace series is a good one, Nickey Hayden grew up riding this series on a MC, there a lot of Yamaha riders there....

post # 18

http://www.trx450r.org/forum/index.php?sho...15&start=15

i appreciate the info..... but they would have to be in chuckie's pro EDT class for me to sponsor them.....

i already told chuckie i would build him a yfz if he was interested...but he bleeds red only.....lol....

another thng that is bugging me about this nasty little pump gasser....

is that it keeps making more power right up to the rev limiter at about 10,600 rpm.....

sometime i have to get a dyna ignition just to see what the rest of the curve looks like.... if only money grew on trees...lol....

if you remember how the EDT pro class looked last year.... there was a lone yamaha back in the pack..Mezo told me last weekend he switched to Honda for the 08 season as well... lol

oh crap....!

lol...

so much for that idea.... i didn't remember seeing too many yamaha's....

but now i'd like to give one a fighting chance for the sake of not having the races look like a Honda parade....

Awesome tests John! I want to add that the Webs in the sredrum 480cc (to my knowledge) are the 187 +2.5's I presume the exhaust is retarded 1 tooth. Webs still makes 1 cam higher for top end called the 187+5's. I believe the 187+2.5 are closer to a set of Hot Cams.

On the billet RW cams... I believe they too need your cores but only for the cam gears.

Looks like it is still hard to squeeze out more TQ out of those smaller motors. Rev to the moon and good for HP, but I never seen a real TQ gain until my 480cc 98mm bore, and I suspect a larger TQ gain with the +3 stroker.

The dip in power is cuz your not as cool as me! haha...

no dip in this badboy



ALL WITH HOTCAMS

DAMN im glad I did not spend $400 bucks or more on some woods...and im glad i did not buy webs...everyone is convinced the webs kill the hotcams...but ive yet to see the proof...

anywho...thanks for the testing mixx...my hotcams are staying firmly planted in my head!

Just for clarification are you running stock as stock, or cam modded.

graet info john... thanks for all your testing and sharing

Im curious about this dip.......reversion during overlap! Its a pump gas piston so little or no dome, right?
What happens when you up the comp with a piston with more dome?

58HP 439cc is impressive!

yes, very impressive... on pump gas nonetheless.

wow... cant wait to see what it does with the hotcams exhaust cam... and the hotrods stroker.

Christ John.....your right at 2.2 hp per CU......on pump gas!

Stock yfz pistons are dished concave. Perfect for flow.

HEY ERIC...WANNA BUY A RAPTOR MOTOR????

No, but you know you are going to ask me to pilot your new orange monster!!

haha...i might just have enough horsepower too race my own chit LOL...but you know your welcome to ride the roller coaster!

ive got the mooseknuckles raptor in my sights LOL

yeah i hope ya dont have to have a pilot to win on that thing....lol

which i dont think you will

Nice almost makes me want to buy a Yamaha. Been thinking about it.

i'm pretty certain it's reversion during overlap......

the 5-valve setup from yamaha has more flow area at low intake lifts than would a 4 valve arrangement...

since reversion happens during the low lift phases @ overlap... the yfz would be more succeptible to both the positive AND negative effects of suction OR reversion during overlap..... and negative results are normally in the RPM band we are looking at here.....

i'll see what i can do......

the 58 hp thing is sredrums high comp 480..... i'm only at 56.6 with 439cc on pump gas....

high compression would take the torque...and hp up a little bit.....and adding 11cc's to make it a true 450 would add in a little more.....

but...the 4-valve and 5-valve engines are different beasts as far as power delivery is concerned...no doubt about it....

one of my friends calls the yfz's "3-Strokes" because of their hybrid 2\4 stroke powerband....lol...

thanks for the hook-up paul!

i thought about it........ it was a bit unfair to test only the Hot Cams intake cam VS the Woods cam set of both cams.....

and called paul for another hook-up on the hot cams exhaust cam...and paul told me he knew i couldn't stand not seeing how it would work with both cams...and that he almost went ahead and sent me both cams in the first place even though i only asked for the intake cam...lol...!

re-test coming up as soon as the Hot Cams exhaust cam gets here....... then it's on to bigger & better things.....

i'm going to point out another internet myth that doesn't hold up to the light of day......

yamaha forums have been denouncing the hot cams as only making more power on top end while taking away bottom end (that's kind of how all cam timing in general works anyways).... while they like to act like the rest of the cam world adds power across the board.....

couldn't be farther from the truth.......

i'm pretty sure the Venom dyno ...aka buster (myth buster lol)...has seen more yfz cam variations than any other dyno......

and ALL of the aftermarket cams lose bottom IF they gain power on top...... and some of the super loser cams...like everything from Crower....just plain lose it everywhere......

the one thing i know for a fact...is that the only truly valvetrain safe...full base circle cams tested so far...have been from Hot Cams.....

and i don't sell cams.... i only care to recommend what works...and lasts....

My bad..... I got all caught up in the numbers, lol! Your still at 2.1 HP per CU.
So low lift at that RPM causes the negative pressure or reversion?

nope... reversion is a dynamic of pressure harmonics in the exhaust and intake tracts...

low lift is what the valves are at during overlap...

and at that point is when reversion can be a problem....

Well Well Well there Mixxer.
Very Nicely done.
I am very excited to hear that you got it working like you wanted.
I am prtty excited to see the next version of the build.
Keep it up big dog!

Soooo......the reversion during the overlap period at those lifts is caused from the exhaust not pulling out the spent gases and they travel up the intake tract?

thanx Mr. Gray!

i couldn't stop if i wanted too.....

and i don't want to....!

that......and it could also be from any one of the many phases of harmoic events in the intake or exhaust tract being there at exactly the wrong moment.... there are all sorts of pressure wave highs and lows from either end that can contribute to it.....

the exhaust could have pulled everything out...and a returning positive pressure wave could push it back in..... the intake could also be under negative pressure wave return at that point and stall the incoming fresh charge....

there are so many harmonic cycles going on in a running engine...... more overlap is great when everything all lines up for the good....but leaving the "window open" for a long period of time also leaves the opportunity for a negative event to take place at some rpm band....

go john go!


i wanna see 65 horse before your done!

i'm on it Mr. Jones!

and BTW...thank you very much for the stock yfz cylinders..!

one is already on its way to U.S. Chrome for a 98mm bore.....

next stop pre-501 stroker is going to be 470cc's @ 14.25:1 compression.....

up 30cc's and 2 points comp from where it sits now.....

in the meantime i'm waiting for the Hot Cams exhaust cam that Woodward's is hooking me up with.....

No problemo john~!

glad to be of service...besides they were just taking up space next to my bed anyways

NOw...if only CHM would get cracking on our yfz pipes so i could go riding! ( just busting your balls )

the Venom pipes have taken a back seat to production of thier own lineup for 08.... right now the rhino is #1 on their importance list....oh well... i can understand that they have to take care of their own stuff first.....

but a performance quad taking a back seat to the equivalent of a single cylinder jeep ??!!...lol... it just isn't right IMO.....

[quote name='JJONES660' date='Dec 21 2007, 12:55 PM' post='434801']
No problemo john~!

glad to be of service...besides they were just taking up space next to my bed anyways




Jones you keep a cylinder next to your bed.......??

Man, some of the best testing/info on the YFZ is right here on a Honda site! Maybe I should start coming over here more often.

Jones I saw that GSXR YFZ you just picked up--Damn!

Now I really need to meet you out at Killpecker!

Couldnt the dip in power being as simple as the cam "coming on". It gets to that point where its ready to syncronize if you will with the rpms of that setup?

I see this dip with the Johnson cams and the bigger mega cycle cams on my Honda.....It just seems prevelant in bigger, higher duration cams. But like John says, the more overlap with the bigger cams makes the setup that much more touchy.

Anyway, John you sure know how to build a bad ass motor. Great job and cant wait to see it fully built!

i DONT think it is in the cams...ive had the dip before too...but was usually a result of stabbing the throttle on the dyno or a jetting issue somewhere in the circuitry....but who knows for sure...i have not seen that dip in a LONG time on my bike ..but who knows...im not the expert im just a guy bolting poop together


dirty carl...rocksprings is on the list for 08...but most time will be spend in walden if you wanna see it in action

and YES there are motor parts in my room and sometimes near my bed LOL...right now there are a few jugs of Oil and a rear bumber near my bed LOL...somehow or another chicks never seemed to mind cuz thats just who i am...

bigger cams = more overlap = bigger window for intake\exhaust pressure harmonic's positive AND negative effects to happen.....

the rpm band this is happening in is exactly where negative reversion effects happen...

nope...definately not jetting or throttle stabbing Mr. Jones.....

remember... during your testing, you were using the most reversion resistant exhaust system ever made...

HAHA...gotta love the old pulsechargers....they got a dirty rap by many...but ive yet to see such a smooth band as made by the open core PCs...

There has got to be a way to build them things again in a sleaker light weight design...im gonna miss mine thats for sure

AGREED Still the best all around pipe I've ran on the
YFZ

Ya that PC performed good on your bike and I wanted to try it out on mine but the coolant lines would'nt allow me too from what I remember. Can't wait to try out John's new pipe!

prototype work is pretty much done.....

but i'm still at the mercy of the time schedule of CHM for production versions.....

sucks to be a small company sometimes....

Can't wait to see it bro. Keep up the good work!