250sx performance exhuast

[SCRAMCHARGER318]

i purchased a cobra exhuast for my sx, but i didn't intend on it being insanely loud like it was, so what i did was went down to the local tractor supply company and bought a canister muffler for a 1976 international farmall tractor, and it worked great! much better at full throttle without sacrificing flow, i just took the bracket off the cobra muffler and welded it on. i used the cobra front pipe( becuase it's larger than oem and cut the cobra muffler of and put the tractor muffler on, for 30$ anyone can do this and it's cost effective, you don't have to use a cobra front pipe u can just use your factory front, thought i would share that with every sx owner, also if you want a ignition upgrade rick's performance makes a hot cdi for 70$ it provides multiple spark and has a increased red line of about 1000rpm, but unfortunatly the stock sx cam is done at that rpm, but if you put a bigger cam in it you can use that rpm for a higher top speed! only downside i noticed is that once i put it on my bike ran rich due to the multiple spark, so i put a stock main jet back in it and it run's like a cheetah on cocaine for a sx.

[maxfior]

pics of the wild trator pipe setup?

[piroguedog]

Hmmmmmm. So, youre shooting for quiet and fast? I would have thought that the tail pipe would have been the performance "giver" so if you ran rich with the tractor thing, you choked off the air flow, then requireing less jet. I am fairly new to the gas/air flow thing so i may be off. I would think that an increase in performance would have some noise increase as part of the package.

[Dirtcrasher]

I'd bet that one of the best/cheapest/easiest upgrades you can do to a 250SX are a 350X carburetor (fattened up) and a 450R S.S.Exhaust can... The stock SX can is about the same size - I imagine the 450R would be an easy swap.

They work great on a 350X and I've even seen them 200X's.....

There's an HRC tip for the 450R muffler that allows you to fatten up any main jet and sounds great too....

Of course the Supertrapp is my favorite exhaust!

[SCRAMCHARGER318]

Hmmmmmm. So, youre shooting for quiet and fast? I would have thought that the tail pipe would have been the performance "giver" so if you ran rich with the tractor thing, you choked off the air flow, then requireing less jet. I am fairly new to the gas/air flow thing so i may be off. I would think that an increase in performance would have some noise increase as part of the package.

well i was shooting for a relatively quiet but better flowing than stock, it's louder but nowhere near the loudness of the cobra, especially at full throttle. reason i had to lean the jet was becuase of the cdi box it puts out more energy and is multiple spark. that means it burns the fuel more completely, so there for less fuel is needed, if you don't rejet it will probably run rich, and it did in my case.

[Tri-ZNate]

reason i had to lean the jet was becuase of the cdi box it puts out more energy and is multiple spark. that means it burns the fuel more completely, so there for less fuel is needed, if you don't rejet it will probably run rich, and it did in my case.

if it burns the fuel more completely that means you can put more fuel to it to gain more power. Getting a hotter, more complete burn makes a engine run leaner. Just try putting a hotter heat range plug in your engine, its the difference between rich and dangerously lean.

Biggest gain with an SX is what crasher said, throw a 350x carb on there and let it breathe

[piroguedog]

i've been having a 350x carb as a future swap for my sx but i didnt think that it would make that much difference. can someone explain the diff it could make. I have a k&n filter with no airbox lid, 14 plates on my super trapp and my stock carb jetted with a 155 main jet.

[POS 250sx]

How do you not love the cobra? i love mine. Whats the best way to aqcuire a 350x carb? and do i need a new throttle cable? Is it a drop in replacement or do i need a larger diameter intake boot? How big of a gain would u get with 350x carb and a cam?

[POS 250sx]

btw would any of those mods ruin my low end? my sx does more chores and hard work than most utility quads, it hauls alot of manure and lumber so all revs and no guts would kinda be pointless for me.

[Tri-ZNate]

350x carb is larger and flows more air.

I found they add more grunt throughout the range but most noticable at low end. Also i was able to pull the front end up in 4th and ride it compared to 3rd gear before

take the 350x carb and throw it in there. Your stock intake boot, throttle, ect swaps.

More fuel + more air = more power

[SCRAMCHARGER318]

if it burns the fuel more completely that means you can put more fuel to it to gain more power. Getting a hotter, more complete burn makes a engine run leaner. Just try putting a hotter heat range plug in your engine, its the difference between rich and dangerously lean.

Biggest gain with an SX is what crasher said, throw a 350x carb on there and let it breathe


actually it burns more fuel completely yes, but since it's getting more out of the fuel your using, you don't need as much, had the same thing happen when i put a msd ignition on my ol' dodge dart, i was able to lean out the primary jet's and got a little better fuel economy. neither of em run lean, my sx runs great now and plug looks good. the biggest gain i have noticed so far is running no air box lid. everything else helped but somtimes you have to tune 'em to get the most out of'em.

[POS 250sx]

I can pull mine up in 4th and its stock except cobra and KN. Well unless whoever owned it *Edited**Edited* me did somthing to it internally. I got a vid of me jumping a bump on myspace do a search for 3wheeler.

[peco250sx]

wow there is alot more 250sx upgrades than i thought im going to need to get a better job to finance all these upgrades, lol

[Dirtcrasher]

I'm telling you guys, look into the 450R exhaust with the HRC tip as a great improvement!! I've won them for 10$ and as much as 30$ and most of them are pulled off when brand new. You'll definitely be able to fatten up the main jet, yank the airbox lid and it's still a great sound that isn't unbearable like the Cobra or DG. That HRC tip cost me 25$ shipped.......

Of course it isn't a bolt on, but it can't be too hard either. If I have to do it myself to get the benefits out there to everyone, I will...... Would work best with the DG or Cobra headpipe as they are a bit larger.

[peco250sx]

cant you get fmf turbine exaust for 250sx

[POS 250sx]

what if i like how loud the cobra is? The HRC isnt better if i dont mind the vroom?

[Tri-ZNate]

Scram, what jets are you running in your Sx right now?

[SCRAMCHARGER318]

Scram, what jets are you running in your Sx right now?

I am currently running a stock 130 main jet, the rest are stock i'm guesing when i took it apart to clean months back everything still looked original,but i did not run the numbers.

hey guys i want a opinion, check this thing out.
http://www.cyclepages.com/ProductDetails.aspx?ProductID=4031185
if it does what they say, it would be worth the money but i'm very hesistant to believe gains like that.

[slow200s]

I just got a 250sx and it has the cobra exhaust, HC piston? (said to have), 350x carb. I just took off the carb to clean it because the plug was very carbon fouled. I currently have a 146 as a main jet. I was wondering what size jet everyone else is using who has the 350x carb. I would normally do a plug test with a bunch of jets but because there is no spark I was hoping to find a ball park as to what jet to start at when I get the spark back.

[Tri-ZNate]

I just got a 250sx and it has the cobra exhaust, HC piston? (said to have), 350x carb. I just took off the carb to clean it because the plug was very carbon fouled. I currently have a 146 as a main jet. I was wondering what size jet everyone else is using who has the 350x carb. I would normally do a plug test with a bunch of jets but because there is no spark I was hoping to find a ball park as to what jet to start at when I get the spark back.

134 main will probably be close

[Dirtcrasher]

I believe I run a 138 main in mine....