Well the 650 maybe a little different since I really have had no dealings with them and they are v-twin. However, with MOST machines if you put a after market, higher flowing pipe and high flow filter, you MUST rejet. This is not nuts, just a fact. Most machines maybe slightly rich from the factory or just about right on with their current set up. By adding a higher flowing exhaust and filter you are tremendously increasing air flow in and out of the motor. If you increase air flow you must also increase the amount of fuel. If you do not you will be running the machine lean. This condition WILL eventually destroy your engine. Anyone who tells you different is nuts. Call and ask any pipe manufacturer or filter manufacturer. You MAY not have to rejet if you simply add one or the other, however, when adding both you most always have to rejet.

Again, I have no dealings whatsoever with a Praire 650. However, I can tell you that my Lakota was very lean after simply adding a pipe and filter. A Mojave my buddy added a pipe and filter to also was VERY lean b4 jetting. The only way to see what your motor is doing, other than a dyno, is a plug reading. You can get very good instructions on how to read a plug on Trinity Racing's website, or better yet, call them! They will tell you what they think about this as well.

I maybe nuts, but my machine runs properly.

 

Stebob, tuning my v-twin has been very similar any other quad (especially 4 stroke with a cv carb). Same principles apply. There isn't really a difference. You do have to keep your wits about you, since if there was something wrong with one cylinder, it would be harder to hear and figure out, and you couldn't really make jet changes.

Realistically, the correct answer to gatrons question, is "You need to verify that your jetting is right after changing the pipe and the filter". It is true that sometimes the jetting will be right on, and it is also true that sometimes it will be off far enough to cause damage.

My muffler mod made mine a touch leaner, and I went up one jet size. My airfilter made mine a hair lean, but no biggy. I waited to do the muffler mod before rejetting.

 

Makes sense NYROC. I appreciate your input. Let me ask you: have you ever seen a machine that had an aftermarket pipe and high flow filter put on and the stock jetting be ok? I'm just wondering becuase in my experience I have not. Your experience is prob. much more vast than mine, so I'm just curious if you've ever seen stock jetting be ok after adding these items. Thanks.

 

I have not actually seen one not need rejetting yet. My experience is not vast, I have piped and jetted 5 or 6. I just read a lot of forum posts, makes me seem more experienced that I actually am.

I honestly believe I am going to see one soon. Although I fell it is uncomon, a Prairie I work on (my brother's) is the richest factory set motorcycle/quad I have ever seen. We may not need to rejet it.

 

jetting depends on density altitude the factory trys to meet every need. One of the best performance enhancements you can do to a stock bike is make sure it is jetted correctly. Some may find their bike lean some rich some perfect it all depends on the area you live.
First fun your bike wide open if it runs fine go up one main until it runs bad then drop back down, then (autosare more dificult to jet b/c it is hard to pick an RPM range) from a few revs above idel gun it if it hesatates or bogs raise the clip dropping the needle then try again until going up or down until it does not stumble. then run at high RPM and chop the throttle it should not pop if it does adjust the idle air screw if you have to go more than 1 1/4 turn out go up on the pilot jet.
Once you are set up the idle air screw will be what you touch to adjust for air temp and humidity both affect density altitude, if you find your bike hard to start you are lean, popping on decel is lean run on on decel is rich. It is an art keep notes.
Remeber your motor is nothing but an air pump more air in and out means more power but if you increase the air in you need to increase the air out which means you will need to increase fule as well that does mean you have to rejet. You are doing the right thing by changing both jest changing the pipe will sometines add some torque in areas just b/c of designe and you might not have to rejet but changing both almost always means a rejet unless, as someone mentioned above, your bike was rich from the start then you may be OK.
P.S. lean on a 2 stroke is very bad b/c oil is mixed w/ the gas and that is all the lubrication you have. As for 4 strokes there are 2 schools of thought rich of peak EGT(exhaust gas temp) some say is the way to go some say lean of peak EGT is right. 14.7 to 1 is perfect and should produce great power and max EGT lean of peak 12 to 13 or so will produce more power, will it reduce life? I am of the school that it will that is why I always lean my airplane to rich of Peak EGT I know a bunch of pilots who run lean of peak, they say they get better fule economy and that it will not hurt your motor ever, after all cooler is cooler. Now if millions of reserch $ has not proven a dif I doubt that a H.S. kid or average ATV rider knows either.

 

I installed DiamondG snorkle, which offers much better air flow. Installed K&N Filter, and Big Gun exhaust. I rode the quad several runs on a test strip with stock jetting. I was timing my self to see how the mods effected the power. In this test run I had an ave. 8.25s. runs with all mods and no jet kit. I monitored the color of the plugs, and also checked for hesitation in acceleration. The color of the plugs went from black to brown after the mods and noticed no hestitation or popping. I then installed the jet kit. The color of plugs look the same and now my average time on the test run is 8.70s.

So the question is. Is jetting always needed? In my experience the stock jets are to rich and after mods will be more effective.

 

I will stick w/ my post my bike was lean as hell when I got it, you need to determine what you have. It is obvious your was rich and I aplaud you for testing your mods, to many people add a pipe loose power but b/c it is load swear they gained 50 hp. The way at least gives you have a base line to go by and you can see if improvements are working.
However your results are not going to be the same as everyone elses results, and I did not say he had to rejet I said je had to do what you did and test to see if he needed to.

Not do me a favor, remove you airbox lid and re-test you will see how much more air gets in and your bike will be lean.

 

OK..I think I goofed and would like to know if anyone has an opin...I put the Snorkle on today but the jets proved to be formidable..as in the cheesy brass screws were not cooperating..so I bagged that idea for the time but now it stumbles when punched coming off the bottom..I would say im getting to much air now but can that be corrected without taking the thing apart and putting the stock snorkle back in..???

 

That stumble usually means the needles are off. The dynojet neeldes are usually set to rich (per instructions) so if you did it all at the same time, you probably did the needles too rich.

You can't tell if the mains are right by stabbing it, you have to hold the throttle at at least half to know how they are.

Also make sure your air screws have been turned out a little like dynojet suggests. I suggest 2-1/2 or 2-3/4 turns, works best for me.

If your stumble is worse cold than hot, it is lean. If it is worse when hot (mine), it is rich.

good luck

 

Block the end of the snorkle partially with duct tape. If the stumble goes away you were lean, if worse you're rich. Nyroc's probably right; the adjustment will need to be made at the needles.