LOW power, given my jetting ?

[buckyworld]

nosgsx: 
not a progressive controller.   all or nothing.

i've not scaled it, but i'm confident that the bike/rider/gear weigh 660 pounds, give or take 10.

i know i'm not cramming too much juice in the motor, but i sometimes wonder if i'm trying to cram too much , too far from the intake port to assimilate with the airflow properly.  yeah, you're right.  that sounds like a crap theory, doesn't it?

i'm NOT POSITIVE i'm getting liquid nitrous at the nozzles.  i'm sure some of my hoses could be a little shorter, but nothing runs past hot surfaces, and the summer temperatures here are pretty cool compared to...anywhere that ISN'T alaska. 

last year, when there were other variables fighting me simultaneously, i tried running with the bottle upside down.  results inconclusive due to those other variables.   i am going to take apart my bottles this winter and double check for a siphon.  everything i read says that a NX 2-pounder comes with siphon tube, but at this stage i can't take anything for granted. 

i get a serious "kick" when the juice hits, but i am thinking i SHOULD have a 9.5 bike/rider combo here and am still looking for nearly a second of elapsed time.  right? if i can run a 1.64 60-foot time and shift the damn thing, i SHOULD be tapping mid nines with a 105 rwhp bike adding a 60-shot???   i've pulled a fair amount of weight out of a bike that was pretty light to start with too.

 the possibility of getting gaseous nos and not liquid, and/or maybe incomplete combustion due to plugs/gaps appear to be my most likely impediments.

fjman:  "not burning well or something" seems EXACTLY it.  and so far, i've heard VERY LITTLE about people's nitrous giving a hit, but not as much of a hit as it should.  it generally seems to either work or it doesn't for most bikes/people.

at least i'm learning new lessons in patience ~

[WAR MACHINE 1300]

IM THINKING BOTTLE PRESSURE  IS  DROPPING IN MID RUN  AND OR MAYBE  BAD  BOTTLE FILL TRY A BOTTLE  HEATER?   IF YOU  CAN RUN THE BOTTLE  UPSIDE DOWN TAKE  THE SIPHONE TUBE OUT  .

[buckyworld]

i've got a heater.  pressure is at least 800psi AFTER a run...some dropoff but not abnormal.  i've tried different bottle pressures with little change in performance.  and i've made dozens of runs and several different fills over the summer.

unfortunately, both of my bottles are completely full so if i want to check for siphon tubes, i will have to either see if my nos guy will pump it back and forth for me or i will lose it all.  OR, i could just make the first few runs next year trying different spark plugs and setting up my (hopefully) new quickshifter.  i am relatively sure that my (bought new by me) NX 2# bottles have tubes.  but before i refill them, i WILL remove the valves and be 100% certain.

[FJman]

You're not on the juice for a BUNCH of your run.  Between shifts and all of first gear (probably 3s or so in first alone, maybe 3.7s total!)


Airshifter (or get the quickshifter rockin).  I still say you should drop down in jet size a bunch, if you lose much mph that's a sure sign that your motor isn't actually firing the bigger mixture.  Two dyno runs would also reveal this (with rejetting between, know how much of a nightmare it is to swap jets).

[buckyworld]

fjman, i hear you.  dropping jet size a bunch WOULD tell me that, but frankly, i think 134 mph trap speed tells me too.  that there's missing horsepower, that is.  my inclination is to try to make up for lost time with the quickshift, and play with plugs/possibly coils mainly because it's so tough to change jets in my application.


this is the level of teardown needed to rejet.  the horizontal intake runners/ports of the 919 crowd it up under the backbone of the frame.


HOWEVER:  for all i know, the cumulative time spent off the bottle due to shifting lag time and not spraying in first MAY be all of my trouble.  this dang thing COULD run a 9.2 once i keep the system spraying for 2 or 3 more seconds of each of my runs.

so if i don't hear any "AHA !" responses here, i'm going to TRY a quickshift with ignition module.  which as i've mentioned, dynojet DOESN'T  actually make for my application.  so even this step is a $600 guess, and electronics aren't generally returnable.  if i can't get a Honda 919 owner in SoCal to allow a try-sie at dynojet, i reckon i'll check connector configurations and try one for a cbr929 or 954.

but if anyone has any other thoughts on low power for a given jetting, i'd sure love to continue the conversation.

my original point with this bike was to drag it kicking and screaming into the nines, in homage to my late father.  i gotta honor him as i set out to do 3 years ago.

[Nosgsx1300]

okay using the formula
(((mph/234)cubed)xweight)
I get 123mph 660lbs works out to 95HP
        134mph 660lbs works out to 123hp
you are agining ~28hp
deff low with those jets
I would put the .018 nitrous jets in it with whatever fuel go with them for your system(fuel pressure dependant)
aslo possible is is detinating if you put the smaller jest in and your MPH doesn't change that much then I would be worried that that is what is going on

Now the more you are out of the throttle to shift or in the first 60' the lower these numbers will be
when bored at work I compare that formula with the et one
I like to see what percentage I can get with the ET formula
cause the closer they are the "better the run is"

[buckyworld]

the problem in trying to use those formulas is that i KNOW (due to not spraying in first gear, and cumulative shift lags) that i'm making 105 rwhp for approx. half of my run.  i KNOW that i'm making an OPTIMISTIC maximum of 140-or-so rwhp for approx. 5 or 6 seconds of the run. 

so you'd have to modify the equation to deal with those variables.  it'd be like calculating for a standing start 1/8 mile at 105 hp, then a flying 1/8 (110 mph to 134 mph) at 140-ish hp.  more or less.  too much math, and it would still be somewhat guess-based.

here's my thinking now:  the engine hasn't pinged...so i'm NOT too lean on fuel.  my all-motor runs have not dropped off et or mph...so i haven't done internal damage in my experimenting.  i KNOW that my system has to shut off and start up several times per run right now...losing me hp, et, and mph.

so it seems that my first point of focus now should be making sure that my system is on and juicing for a greater percentage of my run.  more important to me than getting more performance when it IS on, make sure that it's on longer.   and as i said, peformance wasn't much different with slightly smaller jets last year.

this looks more and more like i'll have to buy a dynojet quickshift and ignition module on a guess (along with a new pcIII - i bought existing one used and it has cold start issues) ... spending a total of around $1,000.  or seeing as i had Trac build an air tank into my swingarm, i COULD use an MPS air ram w/ ignition interrupt for less money, but the quickshift would be a tidier install and easier operation (no worries about air pressure before my runs, fewer moving parts/ variables). 

it's tough being the guinea pig !  it's tough taking the $ leap of faith !

[craigster]

With NOS systems on carb bikes I've run 22n - 26f in order to get 70 hp.  Not that it will get you to your expected 144 mph, but it should help raise mph slightly.

[FJman]

okay using the formula
(((mph/234)cubed)xweight)
I get 123mph 660lbs works out to 95HP
        134mph 660lbs works out to 123hp
you are agining ~28hp
deff low with those jets
I would put the .018 nitrous jets in it with whatever fuel go with them for your system(fuel pressure dependant)
aslo possible is is detinating if you put the smaller jest in and your MPH doesn't change that much then I would be worried that that is what is going on

Remember that that 28hp estimate is an average of the total run.  It could be closer to 40hp, say... but it's being used for only 2/3 of the total time (or whatever ratio works out to, it won't be linear, either).

I'm thinking that using a smaller set of jets for the same mph is an indication that the motor is experiencing partial burn, detonation, or whatever, and not getting the expected gains.

[Rocketgeezer]

Hi guys;  I don't do much with nitrous any more,but a few years ago did a bunch had mike thermous # on speed dial  anyways as to why low power on the juice?  as I have found there are a few things that can cause low HP when on the nitrous, first is your bottle being filled correctly? I questioned this cause they seemed to runout a little to fast, the guy filling them got pissed, started filling my own. if you try to refill the bottles and they are not empty they may not fill completely with notrous it might have the pressure up but it will be filled with air [small scale may verify this]  then the bottle be positioned correctly so it flows liquid not gas bottle position on the bike and sipion tube must be in right place. your nitrous line must be short as posable and with no kinks or blockage. also if you run a large volume of nitrous it must be big enough, also your nitrous selonoid may not be flowing correctly if all this cks out and sill low hp you may have to much fuel going in for that amount of nitrous and I think I would try to rig someting up so your system comes on at the top of first and stays untill you back off,   hope this helps  

[WAR MACHINE 1300]

GET ONE  OF  MATTS KILL BOXES AND  WIRE  IT  TO  THE STARTER BUTTON OR HORN WHITCHEVER ONE ISNT  BEING  USED  FOR THE NITROUS AND  LOAD THE SHIFTER  AND  HIT  THE BUTTON   IT  SHOULD  SHIFT AS FAST  AS  ANY QUICKSHIFTER  AND  PROBABLY  BETTER  THAN  THE DJ SETUP

[buckyworld]

thanks again all.
DaveC., i have checked those basics, short of replacing a solenoid.  and warmachine, i also want to retard my timing slightly, and the mechanical ignition advancers/retarders out there won't work on my bike.  i wasted $75 trying a difft. honda's retarder to no avail. 

Good news !  i just got an email from Dynojet saying that my persistance has paid off, and they will be marketing an ignition module for the Honda 919.  So that allows me to pull a degree or two out while spraying, use a quickshift (spraying all the way down the track), and select from different maps when i spray/don't spray.  all the things i wanted.  well, i WANT a 9.99 or better too, but i'll just have to wait and see.

of course, i'll only have the small matter of ponying up $600 for the quickshift and ignition modules...

[WAR MACHINE 1300]

ID GET  A  KILL BOX FROM MATT  ON HERE  OR  MPS AND HOOK IT  UP  SO  YOU  CAN FOOT SHIFT IT  WITH  THE BUTTON  IT  WILL BE  A  LOT  CHEAPER  THAN 600 BUCKS    BUT   DO  WHAT  YA GOTTA DO

GOOD  LUCK

[GSXRTURBO1]

I seem to recall Honda's generally having a weak spark, which may be your problem.... I recall someone turboed a Honda bike and had to run very low boost when using the stock ingnition and coils.

I'd try to close the plug gap up to .018", and use smaller jetting. You may get a better ET with a lower MPH, but it's the ET you want, not the MPH.

Give it a shot, I know it's a lot of work given what you've told us, but I think it would be worth the effort. Good luck! 

[buckyworld]

war machine, between my somewhat emotional preference to go with the quickshift and my desire to pull a little timing out of it, i'll probably go with the dynojet stuff.  plus they said they'd give me the prototype ignition module that i pushed them into making !  i wanna show a little loyalty to them for their generosity. 

gsxrturbo1, i am stronly contemplating high energy coils too.  i was getting smooth power (if not exactly thunderous) , which at least loosely implies that ignition events were successful.  i may drop my gaps way down first, to see if that produces any change.  BEFORE i attempt another rejet.

my first project bike, approx. 25 years ago, was my brother's 1976 Honda CJ360T.  way back then, i'd read of the weakness of many stock motorcycle ignition coils.  i found a magazine article about switching automotive ignition coils onto bikes, and did this to my brother's bike.  i think it cost somewhere around $20 complete back then.  maybe it's time for me to scour the archives ?

[buckyworld]

Ignition Module received, Quickshift and MultiFunction Hub have shipped and should arrive late this week.

And I've got about 3.5 months to get it sorted out.
The ONE good thing about Alaska motorcycling:  plenty of wrench time during a long winter.