Do it after as the jetting itself will alter the sync slightly. It say's nothing abut carb sync in the manual, but my tech at the dealer say's that it need's to be checked at the first or secind dealer service, which consists of all the fluid's (which I do myself) belt deflection, valve adjustment, and carb sync, these only need done once a year or every 1000-1500 miles.

 

Is that covered in the warrenty? Valve adjustment, carb synced, belt check, etc.....?

 

Gaff,
Yep while I'm not a big fan of jet kits per say, I do believe in rejetting a bike/quad..
my 2 Yammys (street bikes) were done using stock needles (since the jet kit needles were the same taper) and shimming them, going up bunches on the mains (about 10 sizes) airbox mods to flow more air, & a free flowing filter..on the vstar 650 it netted 7 HP at the rear wheel, not bad for 85 bux including the filter...
on the 1300 it was a lot better, I don't know what the HP #s were since I haven't dynoed it, but airbox mods & free flow filters, opening the exhaust up a little, & more advance in the ignition made it a lot more ridable..(V-4 1300 Royal Star) 4th & 5th were overdirve..gone is the windshield shake at 50 mph in 5th...I had about 100 bux in that, including filter..

if the taper of the needles is the same, why couldn't airbox mods, new filter, & equivalent mains work as well, if the taper is diffrent, why not go up 1 size on the pilots..it worked on my street bikes..

most jet kits have adjustable needles, but with .040-.060 shims on stock you are at clip position 3.5 or 4 anyway.. the pilots I noticed if you go up more than 1 size have a tendency to be borderline rich.. 1 size worked real well..

I'd like to see something similar done to the prarie as well.. if you knew what worked close, & liked to tinker, you could probally rejet/mod airbox/new filter for less than price of jet kit..

CLP

 

Surveyor,

At this time I have not been able to access the dynojet description of the prairie 650's kit. But if some one can tell me briefly what the packing list says that comes with thier kit I will more accurately give you a better answer.

First: On the air/fuel adjustment, This is just a adjustment, not a pilot change. The 3 turns out is good weather you use the kit or not. A rule of thumb on pilot jets and air/fuel mixture screws is, you may go as far as 4 turns out before upping the pilot. Best way to know if it is to lean still is the backfiring. Don't get it confused with the aftermarket header back firing, this is normal for all headers. You can eliminate the back firing by going a 1/4 turn more in most cases.

Second: The needle. The dynojet needle is a more agressive taper and most times longer than the stock one, in most cases. I have had cases were the stock needles actualy worked better. Shimming the stock needles is a age old way of doing it thow. Yes I still shim many of them.

Third: The main. Thier is no substitute for the dynojet mains. They are in no way indexed by number in the same way as keihins. Ones number represents the diameter of the hole, were the other represents the flow of the jet.
The dynojet mains are tapered. Were this comes into play is were it takes the same differential pressure as other mains to flow, it flows more once it does flow. Gives more accurate circut control with less over lapp of circuts.
For instance: If you took your garden hose at home and squirted it threw a 1/4" diameter pipe wich was 1" in length it would take the same preasure to get threw the hole but flow more than a pipe of the same diameter but 3' in length.

Another factor that comes into play that forces me to buy the dyno jet kits is, in some kits you are required to drill out the slide lift hole for faster slide speeds. In theese kits I have to buy the kit if I don't have that drill bit.

Yes I would do my own kits with certain reference of dyno jets kits. I would turn out the air/fuel mixture screw 3 turns (every one do this weather you have the kit or not, it's lean for emisions reasons) use one shim under the needle, and then buy the dynojet mains from dynojet for $2.50 a piece. (Keihin jets are $4.50 a Piece)

This is were I would start. Then by riding or doing testing I would determin what needed to be done. In almost all cases just normal riding threw the woods or what ever over a period of days more accurately tells me were my jetting is bogging me or loading me up. Probably have $20 bucks rapt up in it.

Getting a after market free flowing pipe and modding the airbox on any machine will be a graet idea as far as performance goes. But even just rejetting with a airbox mod will up the performance.

The only reason I ever push dynojet kits on this forum or to poeple in general, is it's an excellent learning tool. You will see every one say, whats up with all this jetting, sounds like a hasle, sounds greek to me. Then ask some one who has used a jet kit one time, they have complete understanding and are some what of experts at it.

I'll give you a hint on doing your own kits, With the stock needle you usualy need a 1 size larger main than some one who uses a dynojet needle. Also in your neck of the woods you will need a smaller main compare to some one who lives in say....Kentucky. Heat and humidity play a big roal in jetting.

As far as syncronizing carbs go, Please guys go buy your own gauge. All it is, is a tube that hooks up to each manifold or carb (wich ever in the 650's case) And measures the amount of vaccume each manifold is pulling. You just use the set screw on the linkage that makes the 2 carbs throttle common and screw it back and forth untill the 2 cylinders pull the same vaccume. It will pay for it's self the first time you use it.

Well I rambled on for to long. I had some thing else to say about it to help you out, but I forgot. If I remember I'll post it.

 

Gaff,
Thanks for the reply..but really what one pays for in a jet kit is the time spent testing & dynoing to get it right..

the tapered needles will definately affect the pilot & main circuts..on my street bikes they were almost identical to the stock needles, so I did not buy a jet kit for 2 bikes, I got the mains right, then the pilot circut..a adjustable needle is nice for tuning the pilot circut..a lot easier than shimming..airflow has a lot to do with jetting..as does humidity, elevation, & temperature to a certain degree..I'm on the gulf coast & the humidity varies down here..other places it is fairly constant..the moisture in the air affects how much fuel can be carried with it through the carbs..I was still kind of hoping for some tech articles (like on the motorcycle forums for members mods to airboxes & jetting, to cut the cost down somewhat..(see the Delphi forum for star-riders.org for examples) I have a set of sticks that I use when I work on my bikes, as well as the tools for adjusting the valves, etc..

A lot of folks don't believe what a diffrence it can make in a stock bike..with a minimum amount of time and $$ a improvement of 10-15% can be had. The quads are restricted in the airboxes almost as bad as My bikes were..the thing about the needles is that the market is closed to get the adjustable ones unless they come in a jet kit..(as far as my bikes went anyway)..I'm not looking for extreme performance out of the 650, I've done this in the past when I raced MX, & out grew it..

the way I llok at it is the more air you can get in, the more fuel you can mix, & the more exhaust comes out..all of those need to be in balance..& stock they are not..for emissions most are running lean, & have restrictive airboxes.

I guess that I'm diffrent from most folks, that I don't mind rejetting a carb, shimming needles, adjusting valves, synch the carbs, etc..to tweak it a bit.. I ended up changing the jets in my 1300 about 5 times, & got fairly good about changing them, it still took about a hour and a half or so..(4 carbs)..

The tapered needles probally affect the pilots about a size or so, so new pilots are not included in kits..

for the average person, a jet kit is good, but when faced with multiple bikes I chose the other method instead..did I really save any $$?, probally not, but I learned a lot..

Thanks..
Charles

 

when they say the Jet kit calls for setting it at notch five and in here every one is saying notch 4 do you have to pull the carbs apart again to set it or not. I am mechanical just I have never messed with the carbs before. I rebuilt one in a car but the was no notches or air mixtur screw so I'm a little new to this and I do want to rejet mine for performance and incase you need it for the CDI box I am learning slowly but it is still some what of a mystery I geuss I will just have to tear into one and see and set them to the forth noth and adjust the air mixture screw to three turns. I will probable find out the end of this month if I have to many problems I will be back asking probably more questions.

 

Charles,

Yah I lived and had a bike shop in Ft. myers for 14 years. Not a huge shop but enough to sapport us drag racing, but that was a life time ago.

I do most kits my self unless some one has no problem buying the kits. Over the years I aquired most parts pieces and tools to many poeples jet kits. Of coarse I have prefferences to each bike how to set it up.


It all depends on how you want to tune your 650. Ofcoarse you can only go so far on a air box without a pipe. Then only so far with a quiet core, but thats how it goes.

Basicly you go as far as you want with the pipe and the same with the air box. This will dictate how far you can go with jetting. Yhis is how I do it. Say you for instance.

Charles what type riding will you do? What type mods are you looking for?

Ok you say you want to add a pipe, but on the quiet side. Ok you ride mostly woods and rock climbing but you don't want to be scared of the water. Well thier you go, either a quiet slip on or a quiet full system. Go as far as the air box lets you, with out compromising water integraty. Cool

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Well you just do those mods, slip 2 shims under the needle, go to the largest jet DJ recomends and open the air/fuel screw 3 turns. The rest is simple jetting weather you buy the kit or not. I also try to stick with tunable disc or cone pipes to adjust for tourque and to keep the customer from rejetting in the winter months.

Your not open coarse racing, so me personaly, I would never suggest a full kit if you or any one else came to me to do the work. Infact I believe you could get very close or better doing it your self, but thats not for every one, ya know.

The needles are good in most cases, exspecialy in super sport street bikes. Let me give you a slim example of how much research goes into the quad needles.

A Lakota, prairie400, prairie 360 all use the 106 DJ needle. The mojave uses a 106S DJ needle. It's a tad longer but put it on the fith or sixth notch and it can be used in the three previous mentioned quads. These aren't the only ones that use the needles, just the ones I can think of real quick.

So jetting your own quad would probably be a good idea, and a savings.

I personaly can't believe the price of the after market of quads. In bikes, street or dirt compatition between companies keep it much cheaper from what I've seen so far.

 

Gaff,

<<It all depends on how you want to tune your 650. Ofcoarse you can only go so far on a air box without a pipe. Then only so far with a quiet core, but thats how it goes.>>

True, the more air in, it's got to get out through the exhaust, No free lunches..

<<Basicly you go as far as you want with the pipe and the same with the air box. This will dictate how far you can go with jetting. Yhis is how I do it.>>

Ya, got me on that one..I like a quiet quad for my work use, as you probally gathered I'm a surveyor & I have my road train parked on a site staking lot corners, or locating things, it has my name all plastered on the doors, so the last thing I want is to be called "you know..that big dude on that LOUD 4 wheeler"...I would like a little more flow of the pipe, but still be relatively quite & be able to ride anywhere.. (now the street bikes a another story..rear baffles removed..just loud enough)

<<Charles what type riding will you do? >>

anything from picking my way from flat ground to climbing banks of holding ponds, to going 50 ft at a time, to running about 1000' picking up equipment..fully loaded with all my stuff on it..that is work use.. I haven't done any fun riding yet, so needles to say that will be more spirited.

<<What type mods are you looking for?>>

you know, the typical motorcycle type..about 12-15 vents in the airbox, either a k*n filter, or a foam filter element, & I'm leaning more towards the foam elements, like a twin air or no toil, maybe modify the snorkle like NYROC did, or Oldman Wheeler..

Possibly a little exhaust work, springs in the tranny, adjustable ignitor box, like a dyna 3K, DTR-(Down the Road) maybe valve springs/cams..Who knows? Just becuase it is 600 lbs, dosen't mean that it won't run well..(you know I ride a heavy cruiser bike..725 lbs)

<<Ok you say you want to add a pipe, but on the quiet side. Ok you ride mostly woods and rock climbing but you don't want to be scared of the water. >>

I come from owning 4wd trucks, & know that they will let you go further, deeper, & farther before you are stuck, then you better have some real good friends...Not a boat you know..but I still want to run as deep as mid calf on the floorboards..but a well made point..


<<Well thier you go, either a quiet slip on or a quiet full system. Go as far as the air box lets you, with out compromising water integraty.>>

Good advice, thanks..

While I like the quad for work, my passion is still the Royal Star bike...I still find it hard to think I spent $$$$ for something without leather or chrome <BG>

Charles