Is all this trouble really worth it...? After you guys have rejetted and piped did you actually see a noticable difference in performance...example:

you have a 1000mhz computer and you upgrade to a 1400mhz computer. You really don't see much differance unless you use a benchmark program and thats only where u can see a difference is in the numbers not actual real life.

I'm just sayin it is fun to mod stuff, hell i know i have before, but a jetting kit and an aftermarket exhaust are very expensive and it seems alot of people with these spend more time troubleshooting problems and making constant adjustments than riding and enjoying the machine.

I just can't see spending the amount of $$$$ i have on my 650 and then spending more on mods that might really screw up the motor just to spend more to get the motor fixed...

Just my opinion, please don't tear my head off =)

 

Um, yah, it was worth it. A little more power overall, but that is not really the reason I did it. The dynojet kit more accurately meters fuel over the changing engine conditions. You look at their website and they describe it better. The shape of the needle is completely different, and the jets orifices are tapered or rounded or something, to give better flow characteristics throughout the jet's range of flow.

It runs tons better at low throttle now. It was rich in spots, and lean in others. The jet kit was great.

Since I read about someone else using the 4th notch instead of the recommended 5th, I was able to get mine jetted perfect after one iteration. No more fiddling.

Also, I upgraded from an AMD1000mhz to an Intel P4 1700mhz. I really did not do it for speed (not a whole lot of difference), I did it because the VIA chipset on the motherboard was not stable using my AGP4x video card. So I am really glad it did it. I will never get another system with a VIA chipset. The P4 1700 system (with intel 850 set) is flawless.

 

If stakk and others are using the 4th notch than this sounds reasonable to me. I have yet to jet a prairie 650, but have been jetting and tuning super sport, and drag bikes for 20 years.

The temp, elevation, and humidity play a big roll in it all. You seem to be well on your way, just thought I could drop on a little insight.

lackdog,

The kits are worth thier wieght in gold. You will notice a big difference rite off. Once you do one of these kits and/or a pipe and filter, you will see. Most of the poeple coming on talking about jetting mainly because once you do it, it shows you that being 1 jet size off can cost you 1 or 2 HP.

Trust me, the stock jetting is far worse than the aftermarket jetting.

Once you dial it in you should be good untill the next mods or when winter comes you bump it up one size to be safe.

Hay sounds like you all are doing graet with these 650's, good luck and have some fun[img]i/expressions/face-icon-small-happy.gif[/img]

 

Thanks for all the advice guys. Instead of jetting down I think I'll drill more holes in the airbox. A friend of mine is a writer for dirtwheels and I asked his advice. They were just got back from Moab Utah (slick rock) testing the prairie 360. He had an opportunity to speak with the R&D guys from Kawasaki about the 650. He asked them about the air issue and they said to "turn the airbox lid into swiss cheese," and jet to match it, this thing requires a massive amount of air. I will do this and let you guys know how it works. I will also open up the front with vents so the snorkel can breathe better.

 

My curiosity is getting the better of me. Could someone please post pics of an airbox lid with twelve uni-vents installed. I'm having a little trouble visualizing this. Looking at mine I just can't see twelve square inches of flat area to put in that many vents.
What are you using to cut the holes. Holesaw or a woodbit?
Also, What the heck is the flat area on the upper left of the lid that looks like a place to store spare change? It's gotta have a purpose or the engineers wouldn't have bothered putting it in.

 

Has the Dyno-Jet helped on the "Cold Natured" problem with the 650's ??

 

Hah!

Wolley, use a hole saw. Do not use wood bits (flat or spiral). Don't use a metal bit either. I guess I would recommend a high speed dril, since my high torque drill ate a piece of the airbox on my truck when it bit. I think the high speed ones won't bite like that. Don't press hard. Wear gloves and eye protection. Don't be all nervous just cuz I said to wear gloves. I say wear gloves because I am a pencil pusher and don't like to risk the skin (or eyes).

The flat spot is intended to prevent pre-ignition when the planets reach a certain aligment in 1257 days from now. Actually it just there for storage.

Sorry, no pic. Try drawing 12 1" circles on the lid (doesn't really have to be flat, seal them with goop or yamabond #4). Keep them from getting too close to the edge and too close to each other (further from edge is more important to prevent weakening the lid). Don't put them in the horizontal space of the flat spot if you can help it. The vertical place is better if they fit. Some guys notch the lip on the flat spot to keep water from staying in it.

Here is a pic of uni vents, if you wanna see them: http://www.unifilter.com/images/Airvents.jpg


Captnemo, others have said it is better. Mine is slightly better, but not really as good as my brother's 400 (almost can't tell it is cold). He runs rich sometimes. Especially when raining.

 

I keep reading that it may need to be rejetted for winter. Does this mean you have to pull the carbs apart and do it or is it an external adjustment?

 

As far as the cold natured problem, the air screw's are set at 2 1/4 turns out from the factory, dyno-jet recomend's 3 turns out whether you have the stock exhaust or aftermarket. this richens it up quite a bit at idle, and just about stop's the coughing and farting at idle. If the carb's are out of sync it will do this also, had mine syncronized and it is smooth as silk now.

 

Should I have them synced before or after I jet it just in case the dealer say I messed it up when put the jets in?