first off i would like to give a BIG thanks for Kris \ NHRAdragracer loaning me his TRX480 for some testing......

a lot of you guys will want to tell him thanx when you see all the good info while his machine was abused with over 250 rev limiter hitting dyno runs...!

first off, kris had originally made this as his "loaner" trx for friends and family... his main TRX is a 530 Big Bore\ Stroker.....

IMO, this 480 was a great combination for a relatively inexpensive, yet VERY well running and reliable build....

i spoke of this 480 last summer from our Silver Lake dune outings...this machine was seriously fast out on the dunes...and only a ride with NO mistakes made on our bigger \ more expensive builds would stay in front of this 480 loaner machine....kris had made a joke while all of our group's machine's were taking a break from the drag race action... it went something like this.... "let's end the loaner\480 out and see if we need to bother with firing up our own rides"...lol...

i have read where several dyno operator's have said that long swingarms make for lessend dyno power measurements due to the added chain intetia and drag.... so far i haven't done any direct comparisons... but i will when i get done with the 501YFZ project... i will finish it all with the stock swinger...and then swap out for a +3" klein swinger that KBR hooked me up with.....the swinger on Kris's 480 is a +4" klein....and my testing doesn't really seem out of line with expected hp results even with the +4" swinger....

anywhoo.....

kris's 480 hit the dyno with this combination:

Stock airbox with HRC lid and K&N filter
Stock Carb
Hot Cam S3
Venom porting with stock size valves & KW spring kit
Venom 14.25:1 480 piston\ cyl
Dynatek ignition

in this configuration the machine read 52HP and mid 36 torque with a SUPER wide torque curve.... the torque is a big part of why it pulled so strongly against the added drag of sand @ silver lake....the higher rev limit dyna cdi was not really necessary at this point since the power curve was dropping at the stock cdi's 9800 rpm point....

the very first thing i did after getting all the baseline runs is pull the machine apart and put bigger +1 valves in all 4 positions....re-working the bowls for appropriate sizing for the bigger valves,,,,and doing the seat work with 4 angles + a finishing radius ....no other chnages..... very rare for me to do only big valves as the only change for a direct comparison....so good info.... KBR had me do several +1 valves in built YFZ's thsi last season ...and they reported 2hp gains.... in this TRX 480 the big valves were worth almost 2.5 HP @ peak... and about 4hp @ the rev limiter.....

power was slightly down before 6400 RPM..... and up the whole way after that... and that's pretty much what you would expect from bigger valves....

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next up....messing around with the stock intake.... i tried runs with the airbox lid removed....the stock resonator box removed...and then a combiantion of the 2.... no real power advantage...and the a\fr jetting lines became very erratic....nothing worth pulling either component with this combination...

so then came the ESR intake.... Kris already had bought & epoxy modded one himself....and i'm telling you he didn't miss a single detail.... didn't leave anything for me to mess with....the original ESR's for the 04-05's were not as short or as straight as the improved unit they make now.....

peak HP went up by about a half.... peak torque went up by about 3/4ths.... power was down a bit below 6400 RPM...and then wider and broader above that point up to the rev limiter....

the results would probably been more dramatic with a larger carb...but i didn't do that comaprison

blue = the baseline 480
red = the bigger valves added
green = modded ESR intake added


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Are you running a Venom pipe on this build?

what fuel?

next up.....

swapping the stock carb out for a work of art FCR 43mm....

Kris bought this carb from Carb Parts Warehouse...and it is the seriesl that has interchangeable \ bolt on rear intake bell assemblies....so a perfect length keihin billet velocity stack\ bell was installed by CPW...no other adapter needed...!

then carb master Sredrum worked his taperboring magic on the whole assembly and made it a fully taperbored 43mm work of art.... SWEEEEEET!.... sredrum also drilled and tapped the bowl for leak jet use...these models come without any leak jet to tailor accelerator pump shot tuning with....

and.......

an awesome 3.5 HP + gain on peak...1 ft lb more tq with a much longer power hold......with more power added from 6000 rpm on up.....!!

and now we hit the rev limiter @ 50 hp instead of the original 40.... making the upped rev limit of the dyna cdi much more useful

blue = baseline 480
red = +1 valves added
green = modded ESR intake added
black = 43mm FCR added

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most of you know i prefer my A\FR jetting lines to be between 13 & 14:1.....

the one drawback with the 43mm carb was that the A\FR line wasn't very consistent...and had a VERY lean peak that i couldn't get rid of unless jets were custom drilled .....

this chart has the A\FR lines of the original 52hp setup with stock carb in blue...

and the 43mm carb in black..... 14's were to be had at each end....but not in the middle.... very lean...
and this was with the biggest main jet that my R\D jet box had... a 238... which is bigger than original Keihin jets go to.....

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wow, i've always said that the bigger carbs are definitely worth the scratch and when going, go all the way. great great results!!! Man I love 480s.

Mix, I hope you were taking notes. I'm thinking of +2/+1s for the wifey's head. The sredrum carb is here as well as the 97mm piston and cylinder.

Congrags NRHA, excellent excellent results.

edit: sorry we keep interrupting... lol

nice info mixxer. that some good testing that really hits the meat of your customers. good budget build. i've been wondering the effects of the larger valves, now i know.

soooooo.... next i called Kris and told him how nicely everything was responding, but i was sort of out of numbered jet sizes....and Kris asked me to try one of the Venom pipes on it....

this last summer we had put a Venom pipe on Kris's TRX530 instead of his HMF carbon fiber system.... we picked up 3hp on the 530...and the main jet size requirement dropped by so much that i thought something was wrong with the dyno's A\FR meter.... something like an unbelievable 18 jet sizes.....

so on went the Venom pipe.....and this time the jetting went from too lean with a 238... to slightly richer than perfect with a 198....quite a huge drop in main size.....

on this particular build there wasn't a huge HP gain like we had on the 530.... on the 530 the pipe swap was a "must do" mod on power alone....

this time the advantages were in noise reduction and main jet requirements.....

this time i also swapped out Kris's epoxy modded yet stock length ESR for a 2.5" shortened one i have for testing...and the results were again interesting...both in power curve and the shape of the A\FR graphing.....

the long intake made more power earlier on...and less @ peak and rev limiter....

the short intake made less until it hit a greater peak...and then held out to almost a 5HP advantage at the rev limiter

long intake = peaks were 58.5's for hp and mid 38 for torque
short intake= mid 59's HP and 38 flat for torque

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and the differences in intake tuning made for opposite A\FR swings with the harmonic timing of the 2 different lengths....

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i love how i always have so many "anonymous" readers of everything i post....lol....

people literally patrol my forum and run to tell their pals everytime i start posting anything....

not enough nads to show themselves.... but never, ever miss any informative threads i post....

keep taking notes...lol....

so finally we have a comparison from baseline to finished....

black = baseline 480
red = completed with std length ESR intake
blue= completed with 2.5' shortened ESR intake

pretty big differences in power curve VS intake length..... the short one has close to 15 hp more at rev limit than the baseline runs have....

i told Kris about the differences in the power curves of the 2 intake lengths and asked if he wanted the short setup
...and Kris went for the wider band with 58.5HP over the lessened bottom end of the 59.5 setup... good choice IMO....

this was already a nasty machine to run against when it was 52/36..... 58+HP & 38+TQ is only going to scoot it along quicker still.....

to answer the "what fuel" question of earlier.... 5 gallons of 93 octane Marathon pump premium with 1 quart of Kemco tetraethyl lead octane booster.... my usual mix for high octane....

hope this thread helps some of you with questions you have had.....

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lol well stop calling ppl out and POST MORE INFO, i gotta know all of this since mine is going to be a 480

this lets me know what i gotta get haha

I would be curious how an Fci intake would do. That's a damn good write up, all that testing takes alot of time and work to do

some extra pics:

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well ive got a question, my final setup will be close to the final except for a few things that i know will add up

you said the dyna was worth it with the added mods

well mine will have a 42mm taperbore carb that i done myself the exact way the sredrum does them
and a stock box with a velocity filter, and stock sized valves and a stage 2 cam

i didnt really want to lose the stock box so thats probably going o stay

but do you think i would benefit by gettting a stage 3, or a dynatek BTW i hate dynatek's

i wish you would of had a stock CDI box to try out on this if you have one will you please try it out i want a comparison of the stock cdi vs. the dynatek

but i will be getting a stage 3 but im trying out the stage 2 first

thanks

John this is the exact same build n power i want...im really jealous i cqant wait but i gotta...lol

WOW lots of testing good job id be jumping loops with 58/38

say hello to Kris's little friend...lol...

very clean machine....1

i hope kris doesn't mind that i added 3 Venom stickers to it... (they ARE removable).... Tress just got in the 50% bigger stickers..... and i couldn't help sticking one on each the radiator scoops....and on the swingarm bearing carrier.....

i'm giving the machine back to Kris tomorrow......

thanks again....!

if only that snow was warm sand..... in a perfect world.....


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Rick,

i thought yours was an 06 model.....?

the dyna ignition was horrible when i tested the 06 & up version.... defiantely do not use one on an 06 & up.....

the real benefit from an ignition is an upped rev limit...or perhaps custom ignition curves to suit a specific build....

with your machine i would use the S2 cam and not try to stretch the rev to the moon...! the S2 makes awesome power...and a huge band....no real need to rev the begeezus out of the thumper..!

nope mines the old trusty 2004 model, and i had a bad experience when i had a dynatek, it just flat out sucked, but thanks for your opinion what i really want is a dynatek or vortec with stock curve programmed to 11,000 but thats alot of money for nothing basically

well thanks man get some more graphs up of this one you said you got 151+ so i say 5 per run so i expect to see atleast 30 graphs lol

yep...IMO skip the ignition then.... use the HC S2 ...live long & prosper..!...

Thanks John and Kris for sharing all of this information

let's make it happen...!

send me your wife's cyl head + a signed \blank check + with the words "tuner's choice" written on the memo line....!

lol

you are more than welcome.... always glad to share info with like minded gearheads......!

i think you guys could take up a collection to buy Kris a fresh set of rings though...lol.... i dyno'd the krap out of his machine...!

BTW... Kris hasn't seen his machine, or any of the dyno graphs ....since last saturday when we met to get his 480....

but i see him reading now.....

Well I'm not anonymous, and I gotta say this backs what everyones been saying.
I gotta go big!
The side by side on the carb tells a good story. Sad, but good.
Sadly, the 43mm FCR will be at least a year away for me, but man o man o man o man do I want one.
Now more than ever!

i hear you jesse!

the 43mm really made for a stunning gain on this 480...and i'm sure it would be more on a bigger build...

i have to admit... while i knew it would add power... i didn't expect fully 3.5 HP...! FCR carb + taperboring is definately not cheap!...but it certainly does deliver....

sorry but it was one of the cheapest mods ive done was my taperbored FCR mine was FREE lmao

traded my stock 04 carb, and a extra set of spindles and my stock a-arms, for a 06 fcr and i bored it myself lol so it is possible for it to be a VERY cheap mod

what dynabox was run on this machine?
programmable?

Nice Mixxer! Good solid info, that is one heck of a loaner! lol

That big carb does add some good power... but don't you compromise a bit of throttle response versus a smaller FCR?? Guess it depends what your goal is.

Excellent info John!! Thanks for sharing all the valuable data that hopefully many will benefit from!

Just wish you wouldn't have posted a picture of the stroker sniper though!!! Makes it much harder to sneak up to the starting line incognito and put the smack down on some unsuspecting victims, lol.

Plus, I'm alittle disappointed that in the picture there isn't a puddle of oil and the crank hanging out the front of the cases. Lord knows it should have been after 250 pulls....

Guess I'll have to wait awhile longer before going to a long rod stroker setup on the "Instigator".

Again John, seriously, thanks for taking the time to do all the testing. I'm glad I could help out in my own little way by providing the "test mule".

I've said it many, many times before, but once again, I feel the Venom 480 setup is the best "bang for the buck" setup I've ever ran....

Later- Kris

Kris, seriously, i tried my best to blow it up ....and have it oil down my dyno.... lol...

250 runs to the rev limiter & no luck....my throttle thumb got tired....

sorry...

very good info and writeup, let us know where to send money for a new set of rings for his bike. thanks for the great info and time to write up... greatly appreciated by everyone, anonymous or not. the dyno results never cease to amaze me of bang for your buck kinda stuff.

Good info John... Thanks for taking the time to show it.

Excellent info John. Boy does that take ALOT of time to dyno, tune, machine and tweak parts, and then write it all up for us to view. Simply amazing bro!

Agreed. Nice write up John!

No. Throttle-response-wise, there is no difference, you couldn't tell the difference at all and in some cases, depending on how much the motor is pulling air, a bigger one in this case could be more responsive as it lets the motor get more air quicker. There is not a single downside to going with a 43 or 43.5 over a 42, a 40 or even a stocker.

Great info as always!

Gotta love the 480......great power for less dough!

Now all this bag carb stuff begs the question.... why stop at 43mm??? Why not 44 or 45mm????


I expect to start hearing things like, oh that's too much carb for a 500cc machine (or thereabouts)... but I think it is worth testing to see what happens.

Anyone got a Lectron 44 they can send to Mixxer for a test - unless you already have one....

John I hate you and all that you stand for...

Why wont my stock bore pumper blow up??!?!?!?! Seriously

I think your getting pretty limited in amount you can bore off around 43.5... there's a point to where there's not much material left and to do a 43+, you generally have to replace the ring to start with.

The Lectron 44s are said to work awesome but they're more of an all-or-nothing carb, harder to regulate part throttle positions.

isn't it getting close to time for a 'fresh' top end anyways.... wink wink....

WOW
Thanks Kris and John fr your time and willingness to make this public.
The 480's rock the house! Always have and always will.
If I ever blow up my stoker build its back to the 480 for me.
We have tested all the way up to a 48mm carb on our big bore stroker builds and it seems like anything past 45 is not only not making more power, but it willt ake away over rev.
Kris has an amazing stable!
Scuderia Stoner!

looks impressive from top to bottom....thanks for sharing

pretty sweet!

the loaner bike...LOL..i love it!

my loaner bike was the ole rappy...but now since the intro of the yfz750 my yfz480 has become the loaner (soon to be 501_)...damn...i wish i had friends that would loan out a pissed off 480!

NIce job!

amazing how the good clean reliable power unfolds when you pay attention to the details and build a CORRECT COMBO....theres more to this whole thing than just displacement alone...wish some would get that...

anywho...congrats john and kris...good job fellas!

stock cabrs can only be bored to 42.5mm and thats cuttin it realy close, the 43mm bore jobs price wise goes up due to buying a aftermarket venturi

Nice results.
I also noticed you have the smoothing set at "4" , Why not 5 like on all the other graphs posted ?

must be a mouse mistake.... i like to keep the smoothing filter set at 5....i like smooth graphs..!

i'll check it out

what he said^^^

of course there would be a point where the carb would loose response by being too large....


BUT..


for the well designed FCR's ...with their flat slides and accelerator pumps.....and being beautifully taperbored by someone who knows carbs (sredrum)..... the response is still razor sharp @ the 43mm point.... it seems even better after sredrum's taperboring work than they do before at the smaller bore...

the Sand Drag junkies @ KBR and Hansen Performance have carbs the size of toilet bowls laying around their shops....they test with a lot more truly BIG carbs than i do....

the deal with bigger and bigger carbs goes something like this:

as long as the engine has a need for it, you will see an increase with each mm you go up in carb size.... then at one point your next jump will not show an increase.....and the next jump will actually hert the power output & response....

what happens is not that the bigger carb will not have enough flow are to produce power...but the lessend vacuum signal of the engine VS giant carb makes it so the atomization and mixture quality becomes less than ideal for efficient combustion....once you get the power to drop off, you are about 2 jumps too big for best performance....

general guidelines only......

laugh out freakin' loud....! lofl..?!

is that an actual portion of the oath you have to swear before initiation to some atv websites or what??

you funny man you...

i'm jealous of the new machine you have listed in your sig.... CRF250...!

riding off-road in michigan, i was much faster on my wifes modded XR280 than i was with my XR400... more nimble.... less tiring too....

somehow i couldn't resist buying a CRF450X....maybe i'm engine obsessed...or just don't learn from old lessons....

but the 450X is definately more of everything than i need for michigan woods riding.... pulls nice wheelies though...lol...