Re-jetting?

[jimmystartup]

OK, I've done gone and ordered a set of Venom SS cans and picked up a K&N air filter. Now for the dumb question. I don't have any experience re-jetting a carb. Where should I start looking for parts, installation advice, etc.

[porterb123]

Try a search on the board for carb jetting.

Factory Pro and DynoJet both make kits, I think. Mine is fuel injected, so I have not rejeted in the last few years...others here have though.

Porter

[bartonmd]

BY FAR, the Factory Pro jet kit is THE way to go... I haven't heard really good things about the Dynojet kits...

I have a Factory Pro kit in mine, and it's as close to perfect as I've seen a not-stock carb'd bike that wasn't "professionally tuned" with an gas analyzer in the exhuast. I have gutted stock cans (flow about like slip-ons) and a K&N air filter and have been very happy with the recomended settings from Factory Pro.

Mike

[blackhawkxx]

I haven't heard really good things about the Dynojet kits...

Well, I have the Dynojet kit and it is just peachy, so..........

[slyxdevil]

all i use is dynojett and my bikes ripp with the jets and exhust mods as i pro tune bikes on dyno

[Lucky]

I've just installed a K&N in a carbed bird and have same the problems everybody else does.

I'm thinking in a factory jet kit, but i'm worried with an increase in fuel consumption.

Can anybody give me an idea of how much will it increase?

[86gn]

My fuel mileage is still in the lower 40s mpg

[bartonmd]

all i use is dynojett and my bikes ripp with the jets and exhust mods as i pro tune bikes on dyno

Is that a lymric? :wink:

Anyway, I'm sure your bikes "ripp with jets and exhaust mods as you pro tune them on dyno," but it must be noted that there is a BIG difference between "ripping on dyno" and running at near stiocheometry in every situation without hickups or rich spots, while at the same time, getting about the same fuel mileage you did stock...

I've installed 4 Dynojet jet kits, and every one of them I've had to make idle so rich it wouldn't hardly idle once it got warmed up, to get rid of the lean spot off of idle... They were all a series of tradeoffs... could adjust them several ways, but no way would make any of them NEARLY as good as the 2 Factory kits I've installed... Don't get me wrong... a Dynojet kit (from my experience) is better than no jet kit, and is awesome at WOT, but I haven't experienced them to be very good at just "around" riding... I've also heard the same thing from several people on this forum...

This is also all just opinion from people who don't "pro tune on dyno"

Mike

Edit: BTW, my mileage is usually 40-44mpg after the Factory jet kit... and that's with no hickups...

[PlasticxxHead]

THIS IS MY PROBLEM EXACTLY,

I JUST PUT IN MY JET KIT WITH A PRO SHOP.. EDDY DYNO.. BUT I CAN'T GET RID OF THIS IDLE LAG,, IT SUCKS.. THE WOT IS GREAT BUT THE BOTTOM END IS KILLING ME..... WHAT CAN I DO. I FEEL LIKE TEARING THE HEAD OFF MY MECHANIC BECAUSE WE CAN RICHEN UP THE IDLE..

Bike takes off from a light and dropps on it's face at 1700 rpm's almost stalls going up hill.. we didn't change the pilot jets is that the next thing to do...

the kit still has 4 gold pilot screws..... should those have been installed with the main jet replacement.???

help. i don't wanna keep going back to this guy pist...

[bartonmd]

OK... check check it...

Read the directions that came in the box... If your application (4-1 and K&N for example) says to use them... do so... Out of curiousity, he DID turn out the idle screws to about 3 turns right?? It takes a "D" shaped almost "nut-driver with no handle" that should have come with your jet kit... Turn them all in until seated (not too hard though, just until they want to stop) and then turn them out 3 turns...

Actually, you shouldn't be doing this at all!!! The guy you PAID to install and tune it should be doing this!! Keep on his until it's RIGHT...

Mike

[Pete in PA]

I got rid of my Dynojet kit for the same reasons.

I kept raising the needle to get rid of a flat spot at 3500 rpm. By the time it was finally gone, I was down to 32 MPG.

I've since gutted my stock pipes, drilled my slides, and now have a great running bike at 40+ MPG.

[Phalanx7.62]

What kind of kits were the K&N ones? I bought one of those off EBay like 2yrs ago. I can't remember if they were Dynojet's or Factory's.

When I installed mine, I used the bigger mains (140?), needle in 3rd pos, and idle screws 3 turns out. Bike runs great, no flat spots, and my mileage is in the 30's.

-Edited to add- I also have Carbon Scorpions and a K&N filter.

[demon]

K&N jet kits are the Dynojet ones. I used to have a stage 3 K&N on my old GSXR. It was a total pain in the ass to get right. Took me a good month messing with the needles (2 sets and both were adjustable), jets (mine came with 3 sets of jets) and screws and slide springs (2 sets) till I got it right. Ran like shit till I got the right combo, then it was perfect.

[slyxdevil]

hell maybe ive been lucky !! i have had great luck with dyno jett kits

i ride my bike in all conditions even snow and no bogs or flat spots

i just follow directions good i guess screws 3 full turns out although they say 2.75 3 is just right i have heard of a few people having probs these people never installed kits before and dont follow directions and bring to me to fix

thats just from past experiances im almost 40 years old and have been tuning bikes, jetskis, and snowmobiles since i was 15 once u dail it in seems to be perfect with out crazy fuel comsuption actully for stage 1 kit you run the 140 main stock your 2 center cylinders are at 142!! and outer are at 140 thats straight from honda for cooling reasons so just running the 140s across board dont hurt fuel mileage

[bartonmd]

When I said all conditions, I meant all throttle/load conditions, not all weather conditions... Literally, every dyno jet kit I've installed has had that flat spot off of idle (with low throttle) I speak of, and been pretty rich in the midrange... Of course, I usually have to go 3.5 turns out to almost get rid of that flat spot, but then it's idling REALLY rich... and if you lower the needle to get rid of the rich midrange, it makes the off idle stumble so bad that I can't get rid of it without makig it too rich to idle right.

I will say that these have all been stage 1 kits on older bikes, directions followed to a T. I'm an engineer who specialized in engine control, so I have a reasonable ability to follow directions and have a reasonable knowledge of how an engine is supposed to run when it's "right." That having been said, I have only installed 4 of these kits, and have only heard the same thing as I'm saying from 4-6 people on this board, so I guess we could have gotten bad kits or something :roll:

Also, do you sell Dyno Jet kits?

On my 'bird, I have a K&N filter (wouldn't have put in, but bike came with it), gutted factory pipes (although I've had slip-ons on it and it ran perfectly with them too as the flow is about the same), and a Factory Pro something 10... it's like a Dynojet stage 1 kit. Needle setting is as reccomended in the directions, running 142 jets all the way across, 3 turns out on idle screws. done. I did have to mess with the idle screw settings some, and they still aren't completely balanced, mixture wise, at idle, but that's my bike, not the jet kit.

Also, some form of punctuation would help in your posts... keeps us from having to re-read it 3 times to figure out where the sentences stop and start.

Mike

[slyxdevil]

no i dont sell jett kits ..lol however i do recomend them to anyone with a carbed bird.. as it was horrible stock when on highway u let off throttle and roll it back on and engine feels flat and so boged down!!!

they tell u in directions of jet kit your bike must idle right first before u install jett kitt !! as kit wont fix it my bike seems to be real responsive

right off idle just like an 1/8 turn to take off from a traffic light a lil more if on a hill .but yaeh some of the older kitts on older bikes were terrible to dail in but.. once u gott it you were great running wise just dail it in and get it perfect and then dont mess with it!! hell ill be glad to let u take my blackbird for a spin u wont find a flat spot anywhere the thing i like about the factory kit is they give u all new colored float bowl screws i think thats sharp and those things always strip out but they do charge u for it as the kitt is like 20 bucks more than dyno jett i recomend dennis kirk . com

for kits as they are pretty good at decent price only thing is it will take 4-5 days to get im a lilttle impacient

[slyxdevil]

also u must take altitude into consideration when jetting im at sea level !

people at high elevation will have to jet differntly i gott a couple of freinds who i went snow mobiling with over the winter who bought new skidoos

anyway up in canada when we went into montains both new machines blew pistons . so that makes a differance so anybody at higher alt. be sure to consult your service manual when jetting the have high alt recomendations in there

[bartonmd]

About idling right before installing the kit... my 'bird idles just fine, but there's one cylinder that seems to have a tad less fuel at idle than the other 3, because on a cold morning, it runs on 3 for maybe 10 seconds before the 4th kicks in...

Mike

[slyxdevil]

i had a suzuki gsxr that did that exact same thing its like 10-15 seconds behind the rest but after that ran like a beast

[slyxdevil]

MY SNOWMOBILE IS A 3 CYLINDER 2 STROKE..AND ALSO HAS A DEAD CYLINDER FOR 10 SECS TOPS THEN IT KICKS IN AND RUNS GREAT!

[slyxdevil]

im seeing alot ofd guys who are having problems also have gutted pipes.

i do not recomend gutting pipe or open pipe.. as bike is designed to have a certain amount of back pressure .. you are much better off spending the money and getting a slip on.. or better yet a full system .. ive tryed mine gutted.. i tried vance and hines slip ons.. (also took packing out of those.also tried slipping a 3 inch piece of pipe over baffles to eliminate..

eventully ended up with a muzzy full system and love the sound and performance i played with pipes trying to get rid of flat spot only thing that did it was a full system problem wasnt carbs it was exhaust now i gott killer wheelie riding low end and still ..like getting shot from a cannon at 6-7krpm to 10.5

example a freind of mine wanted his bike louder he has the r1 ..so he took off baffle, bike was loud as hell but lost all power on low-mid range!!

[bartonmd]

This is true about ACTUALLY gutting the pipes, but what people here are talking about when they say gutting the pipes is actually just punching a hole in the rearward baffle… It flows about like set of slip-ons, and still has most of the back-pressure of a stock system. Actually, I put a pair of Kerker slip-ons on my bike that I was thinking about buying, and the bike ran exactly the same as it does with the hole punched in the baffle.

Also, the Factory jet kit works perfectly with this setup, as it does with slip-ons… The bikes that I’ve had problems with the Dynojet kits either had slip-ons or full systems, not modified from what they came with.

I do know what you mean about taking the baffles all the way out though… when I got my Nighthawk 700S, the guy before had taken the diffuser and end cap off of the pipes, and it was loud as hell, but had no power… Actually, I take that back… I’m sure it would have had plenty of power after redline, not that you can get to it. It’s not that they NEED all the back pressure, but what you are doing when you mess with back pressure is, moving the power around… you don’t get more area under the curve, you just move around where it is. In the case of taking the diffusers/end plates out completely, it moved the flow characteristics such that the power got moved to above redline, and the only problem with that is, the engine won’t run there, so you, in effect, lose that power.

And actually, Pete in PA just recently gutted his pipes... AFTER he had the problems with the Dynojet kit and took it out...

Mike

[slyxdevil]

NI IVE ACTULLY SEEN THE PIPES GUTTED WHERE BAFFLE DEFUSER PACKING AND ALL REMOVE THE ONE KID JUST PUT THE END CAP BACK ON

I HAD TOLD HIM YOU ARE LOSING YOUR DIRECTIONAL FLOW AS IT NOW HAS TO FIGHT TO FIND EXIT HOLE AS BEFORE BAFFLE GUIDED IT OUT .. I TRYED SEVERAL DIFFERNT METHODS MY SELF BEFORE JUST BUYING THE FULL SINGLE SYSTEM.I NOTICED A BIG DIFF WITH THE FULL SYSTEM I GOT NO FLAT SPOTS WHICH IS GOOD I GUESS BOTH JET KITS ARE GOOD AND BETTER THAN NONE .. I LIKE THE DYNO JETT AS I HAD NO PROBLEMS AND THEY ARE CHEAPER ITS ALL THE SAME SHIT ONCE U DAIL IT IN THE BIKE RIPPS MY BUDDY HAS A FACTORY KITT ON HIS OLDER NINJA AND THAT THINGS A BEAST!! IT ALL COMES DOWN TO DAILING IT IN ALL THE SAME REALLY 3 TO 3.5 TURNS OUT NEEDLES IN MIDDLE..I JUST LIKE FREE DYNO RUN THEY GIVE YOU WITH KIT

and yes you move the power around when you play with the exhaust sometimes that will fix a deadspot or flat spot on any jet kitt

[bartonmd]

I actually have a full system... The bike came with a Muzzy Titanium header, but it has a D&D can on it... it's PAINFULLY LOUD! The can also doesn't have any packing in it, which didn't help the power any... I actually have the Muzzy can that came with the system, but when the bike was wrecked, it was caved in, so the guy put the D&D can on it... I called Muzzy, and they said I could get a new can made for $400! Needless to say, I passed. I took that all off after about a week or 2 of having the bike, and Byrdman sent me his holed baffle factory pipes, which I put on the factory header that came with the bike... got a Factory Pro jet kit (new) for $50, and it's about perfect... about as loud as a quiet set of slip-ons and runs about like that too, but the pipes are stainless and STRONG, like the bike fell over when it sunk into the pavement and landed, obviously, on the can... just a couple scratches... would have banged the shit out of a thin, aftermarket can...

Mike

[slyxdevil]

i bet that kid had thad bike flying witrh that muzzy system thats why he chrashed lol i really love the muzzy system shines like a mirror looks chrome but not its the titanium