Had my 400 dynoed today, does this sound right?

[VegasEx'r]

I had my quad dynoed at Dynojet today. It was done after hours by a DJ employee on one of their machines, and so I didn't get a print out of the data (just one of those friend of a friend-type favors). Anyway, the needle is fat & so is the main, and he thinks if I drop one clip on the needle & 2 main sizes, I should be about right, and also pick up maybe 2hp, but what is strange is that it only put out 28.3hp. You can see what I have done in my sig, and I figured I would be in the 33-35hp range. Do you think I am off my rocker, or is the dyno wrong? The other wierd thing is that it runs great. It can beat stock Raptors & z400's in sand drags, it has even beaten a couple C-dale Speeds before (The Dale riders weighed anywhere from 40-60 lbs more than the ex rider, so please don't flame me for what I just wrote). It just doesn't quite make sense, what do you guys think?

[MJNOVA]

Sounds about right. The jetting sounds way fat. 158 maybe a 160... Up on the pilot at least one size. Get the jetting closer and try again.

[AlaskaSpeed]

LOL.....does that count as a flame?:devil

[GoLikeHell]

I just tuned a 426 11-1 and the jets sizes are 42 pilot and 165 main. He also had a whitebrothers E series slip on. We are under a 1000 feet elevation.


I did Dyno this bike for a a/f reading after installing the 426. We left the jets he bought the bike with thinking it should be close. Man was I wrong, it had a 48 pilot and a 155 main. Well when we spun it up on the Dyno we had a 12-1 a/f (way too fat) then once we hit the throttle the a/f went right off the scale! Well after rejetting and leaning out the needle one clip it runs like a champ. Sorry no time for a second Dyno run. The bike did make good HP, but was lacking due to poor jetting.

Did your buddy use a wideband to check your a/f?

Mark

[VegasEx'r]

Originally posted by GoLikeHell

Did your buddy use a wideband to check your a/f?

Mark

He did check the a/f, it was usually around 12-1

[GoLikeHell]

Way too fat!!!

12-1 is robbing you of HP real bad. 12-1 gives the Butt-o-meter a flase reading by being loaded up then clearing and tossing you back on your bike. It feels real fast, but your not making HP, and your torque suffers also. What is your sea level?


I ran my 11-1 stock bore at 17-1 and it made great HP. I dont advise you running it that lean if you dont have the equipment to properly set it up. Bring it to 14-1 or 15-1 and it will rock!

Mark

[GoLikeHell]

Sorry i didnt post this with the second post. This is why dyno sheets are so important while tuning. You might have to change both jets but without sheets you dont know.

Mark

[YZROOSTINYA]

look at my sig

i am at 42 pilot, 4th clip stock needle, 170 main, should be a 168 main. no probs here and my bike ripps.

no choke either

no porting either, sea level

[MJNOVA]

I would bet your bike is fat too. 168-170 without porting and a little cam----I would bet it's way off. It appears to me many people on this forum believe that every tiny thing they do means they need to jet up two sizes. I am not trying to pick at people, but ask if you don't know. A properly setup up dyno is a great way to find out. Given that 99% of the bikes out there never get to a dyno it doesn't always help.

[YZROOSTINYA]

a stage 2 cam is not little!

i had a 42 pilot in and stock needle and my header was GLOWING. that to me means LEAN. along with a 165 main. the plug was also WHITE. so i went down on the needle, went up on the main. no more glowing header, tan plug. me happy


170 is because it is currently 30 degrees out, 168 is prob where i should be at. my plug is a little rich right now, but i dio alot oh hill climbs and typically ride between 5-9rpm. especially on the track.

Vegasexer thanks for that info, its good to get legit dyno numbers since the mfg's seem to get the dyno to allways be off in their favor.

YZ man that is too much fuel, you may want to look into what may be causing it to want to lean out since its prob robbing you of hp too.

The jet sizes your talkin about are where I am going with the 440 for the colder air. No flame man but too much fuel does rob hp.

Then maybe its better to be 2-3 jet sizes too large :rolleyes: if everyone did this (and most do) mine would be so much faster :)

[MJNOVA]

Just to clear it up. I am not trying to attack you or your bike. I ride a cannondale now, but when I had a EX it was a 440. It was pretty well built and was producing about 39-41 HP setup for GNCC racing. I was running a 165 main and a 52 pilot in a FCR. Most of the engine stuff was from Curtis---cam,carb, rockers, head,pipe, flywheel key, valves. The bike was dyno'ed along the way, to properly measure each component.
When I sold the bike, I put the same jetting in the stock carb and it ran resonably well--slightly rich. Jetting for most 4strks doesn't change as drastically as does a 2strk--given the cooler temps.

A glowing pipe would/ could mean lean. First dropping the needle leans it out, not richen it. By picking up the needle you allow more fuel to pass through the main. Please explain the point of removing the choke to me? Take some time, if you haven't already and goto either NGK-Champion or the likes website and review how to read plugs. To properly read a plug you need to look down the sides.

:)

[YZROOSTINYA]

mj

wasn't taking it as attack

i said it wrong. the stock needle is the middle or 3rd clip, i went to the 4th clip from the top, so i raised the needle. when my header was glowing it was during break-in and since i was riding at about 3-4 rpm and barely passed 1/4 throttle your talking about, needle and pilot jets. i raised the needle and that solved the problem. i will try a 165 and see what happens. i am runng a dpr9z plug, ngk. i will pull my plug when i get home and see what it looks like. i know all about looking down the plug.... some people even cut them in half to get a better look. i have a 150-152-155-158-160-162-165-168-170. so there is plenty of room to play with.

the stock carb is a 35 and with the obstruction of the choke it acts like a 33. or so i have read. my quad starts fine with or without the choke and if it helps with airflow then why not? i have had no probs with it now and running rich is not gonna hurt me. other than some carbon build up. i can punch the throttle from idle and it does not bog. if it is in nuetral and i stab it WO it does not put any ANY black smoke(rich condition) nor hesitate one bit.

like i said before i will pull the plug and see what it looks like. this is my 12th motorcyle and i have been working on bikes since i was 10, i am 23 now. not that this means anything as i have seen many mis-informed backyard mechanics.

if i only need a 165 then great, less fuel i will be using. but in the summertime it gets to be around 100 degrees here with 100% humidity and riding on 200foot silt hills alll day leads to a hot otor. if i go a little rich i figure its better than a melted piston. i will give it a whirl and see what happens


:)

[MJNOVA]

Sounds like a good plan to me!

[YZROOSTINYA]

mj,

is gncc like tight woods riding?

if so how often are you wide open?
wouldn't you have a low -mid cam instead of a revver?

could also be why you were leaner on the main, if your never up in the r's or wide open the motor doesn't require as much fuel, also was your 440 a true 11:1 or simliar to the 440's on here with low comp? did you ever check your comp ratio? did you buildd the motor or someone else? 52 pilot seems HUGe, but maybe that because you only ride at 1/4 throttle so it needed to be big.

[VegasEx'r]

Alright I dropped the needle one spot & dropped the main to a 160. That seems to be the consensus here. I will take it back next week to dyno it again & tune it there, if it still needs it. 28hp still seems low, but oh well :confused:

[YZROOSTINYA]

28 is stock

[VegasEx'r]

Originally posted by YZROOSTINYA
28 is stock

That's what I asked him last night. He said that 24 is stock. If you go to GT Thunder's web site, they dynoed a stock ex at 29.4, mine was 28.3, so I guess I am moving backwards :confused:

One of my friends has a 16 year old son w/ a stock 400 (w/ paddles). He maybe weighs 100 lbs in wet clothes. I weigh 255ish, and when we race up comp hill, I beat him by about a dozen quad lengths. How can a net gain of 4hp do that??

On edit: I realize that different dynos give different numbers, but I have seen several dyno charts from stock 400's, and they are usually right around where my quad is now. Maybe (hopefully) when I get the jetting right, the hp will take a big jump, but I don't see how it will gain 5-8 horse. I am just real confused.

[YZROOSTINYA]

you should be in the 35hp range and i should be in the 33 hp range.

the dyno is definitly giving a reading that is not accurate. not so much wrong but the settings are not the same as other dyno's

also vegas, you have to look at the curve also. maybe you are only 4hp PEAK over another 400ex. but look at the numbers at redline you are prob around 10-15hp over stock.

if you look at a stock dyno it peaks at like 6 or so i belive and at 9300 its like 10-12. with a stage 2 and high comp you should be at 25 or so. which is really where you are seeing the differance when it comes to pulling the same gear longer especially up hill because it does not bog down.

[VegasEx'r]

Good point YZ, I will have to check that next week. The only comparison I did was to a stock Raptor run. At 4500 RPM, the Raptor showed 11hp more than mine. Peak hp of the 2 quads was +5 for the Raptor (it was making 33). With that much additional hp (especiually in the mid range), a Raptor should walk away from me in a drag race, right?

[Texan32]

I see you guys talking about a/f ratios. At what rpm is this measurement taken? Or you you take a constant reading? Also, seeing as how there apparently NO dyno's in the state of ND that can handle a quad, where might i look to fing a exhaust gas analizer? My quad never really seems to "load up" with gas, but maybe i AM runnin too rich:confused:

[VegasEx'r]

Texan,
The af ratio is taken throughout the run, so you can see exactly how it runs at any RPM.

[MJNOVA]

HP ratings can depend on settings, dyno, setupand many other things. The thing to do is get a reading on the planned one before you start, this way no matter what other people are getting you can see where you have been and what works. I would agree with the 28-29 rating though. Mine was run hooked to the hubs, which means I should have seen less of a loss then people running on their tires againest a drum. Many after market companies lay down huge HP claims. Most people will never see them. On a quad you can feel 1 HP-- Five is a huge gain.


YZ---My motor was built for TT racing, not CC. I was a 250R person and when I was building my 400 I wanted it to be a revver. It worked for me but most people who ride GNCC's like alot of low end---which I agree would have less wide open time. I revved the piss out of mine all the time. My Cannondale is putting out about 41 HP and it is slightly faster then my 440 was. It feels like it is alot faster though.

[SandTrix]

you may want to take a good check of the rear end. Make sure the bike rolls fairly easy. It is possible that the chain, rear end bearings, over tightened axle nut or somthing of that nature is robbing you of RWHP.

[GoLikeHell]

Originally posted by VegasEx'r


That's what I asked him last night. He said that 24 is stock. If you go to GT Thunder's web site, they dynoed a stock ex at 29.4, mine was 28.3, so I guess I am moving backwards :confused:

**** Dont go by the numbers, go by the a/f readings for right now. If you are at a 12-1 ratio right now you are very rich. I added a Edelbrock carb right out of the box and LOST 3 hp. I have been tuning with a 5 gas analyzer to get my desired a/f mixtures. The carb will add HP, but not till i get it tuned right.

One of my friends has a 16 year old son w/ a stock 400 (w/ paddles). He maybe weighs 100 lbs in wet clothes. I weigh 255ish, and when we race up comp hill, I beat him by about a dozen quad lengths. How can a net gain of 4hp do that??

********The numbers no one ever talks about is torque, that plays a role in this also!

On edit: I realize that different dynos give different numbers, but I have seen several dyno charts from stock 400's, and they are usually right around where my quad is now. Maybe (hopefully) when I get the jetting right, the hp will take a big jump, but I don't see how it will gain 5-8 horse. I am just real confused.

You need to talk to your buddy and see if he can get you a deal on tuning your bike. It will be the best performance gain you will ever pay for.

JMO
Mark