Ok what the deal here?

[Narly R]

Well my friends stock 400ex and my 350r are pretty much the same on top end, I know I have more power than him but shouldnt I be faster than him? I will have my 39mm carb on in a wekk and then Ill see how it compares cause I dont think its reving out all the way, but if he still is about the same I might go to a 14 tooth front sprocket, but well see what the carb does first! O-yea and I have a bills pipe too!:ermm:

that is messed up big time...usually R's smoke ex's...maybe ur R jus sux lol...jj

[XANDADA]

I will go out on a limb here and say that there is something seriously wrong with your 350R if it is having a hard time competing with a 400ex. When you say "top end" are you talking about top speed or rpm range? A 350 should scream like a mofo in the upper rpms. The 39 carb will help a lot. If your still using the stock 34 your really under carb'd for a 350 and probably running pretty lean.

[Pappy]

Originally posted by XxHonda_RacerxX
that is messed up big time...usually R's smoke ex's...maybe ur R jus sux lol...jj

stock for stock a 400 will usually beat an R. ive raced many R's and havent had much trouble staying side by side. mostly its not the power issue...but traction:cool:

[wilkin250r]

Ok, just to clarify, you have a 350 kit, and you're still running the stock 13t front sprocket?

Do you smoke the 400 off the line?

I just put a 340PV in my 250r, and my girlfriends stock 400EX can't touch me, either off the line or top-end speed. When I switched the motor, I also changed from the stock 13/38 gearing to a 14/36 and I still accelerate faster than I did with the stock engine.

With a 350, I'd definitly recommend a 14t front sprocket, it will greatly improve your top-end speed. Some may argue that you will lose acceleration, but I don't think you will. At the low end, especially with two-strokes, it's more about traction than power, and the higher gearing will actually improve your power delivery to the ground.

[sparks400ex101]

yeah if you are at a 13 tooth front sproket and his is stock i can see him pulling you on top end

[Narly R]

Well we raced on a gravel road and he would kill me off the line and all I would do is spin util I hit about 4th!:mad: But then we also got going in about 4th or 5th and I would pull away from him just enough to where his front tires were by my back so were pretty much the same on top end and I mean like top speed when I say top end! I really need to get my carb on it sounds like! Nothing better not be rong with my engine or I will be mad!:confused: :mad:

[wilkin250r]

The 350r is not going to be able to rev out as far as the 250r, and the carb isn't going to help. It will give you more power, but not more speed. With a 350, I'd recommend a 14t front and a 35 to a 38 rear, depending on your porting and powerband. The 35 will give you the best top-end speed, but it may possibly drop your rpms below the powerband when you shift gears.

[Jekyl_22]

Hey!

When I rode your four-wheeler, it felt like it was cutting out once you got past half throttle. Did it run better when you had a smaller main jet in it (before you burned up your piston)? What size main jet are you running?

[Narly R]

Well acually for some reason the last couple times I have rode it it seams to be cutting out more than before like my get is too big, its a 172 I think but if Im at a 72 now which I think it needs a 172 but with a 39mm carb should I be at a 178 or so? Thanks for the info guys!;)

[Narly R]

What do you guys think could be rong with my engine could it just be a pooie kit or is there maybe somthin rong? Its pretty much new!:confused: Ill get my carb on and hopefully get a big Bore pipe that should help, but if it still dont run good o-well Im not going to mess with it any longer!!:( :ermm:

[wilkin250r]

Smaller carbs=smaller jets. going from a 250 to a 350, you may actually go DOWN in jet size because the air velocity through the carb is much greater.

I can't really help you with the specifics of your new carb, but I can tell you mine. I have a 38mm Air Striker, and I run a 185 main jet, which was jetted at sea level, so up here at 3000ft, I'm probably running a little rich.

[Narly R]

Ok well the guy I got the engine from (and he know A LOT about there engines!) said I should start out with a 178 jet and work my way down. But if you have a bigger carb that means your getting more air-flow wich means you need more gas right? Thats the way I look at it..:ermm:

[XANDADA]

Who's 350 kit ya got? Give them a call, tell them what carb your using and they should be able to get you pretty close. ESR darn near gave me dead on recommendation for my carb settings.

I misunderstood earlier, I didn't know you were losing too much traction. On a gravel road your gonna have a hard time grabbing traction with a 350! Heck my 265 acts like its on ice, I can't imagine a 350. Like others said gearing should help. I also think a dialed in carb will help a lot too.

Just out of curiousity, did you figure out why you fried the piston before. Thanks to Harry at Trinity I burned a hole in a banshee piston cause it was undercarb'd and runnin too lean on the top end.

Don't go givin up on the R yet:D

[wilkin250r]

You have to look at the way the gas gets into the airstream. When air moves, it creates more pressure in the direction of movement, and less pressure in the surrouding areas perpendicular to the direction of movement. This is the same way an airplane flies, because the air moving over the top of the wing is going faster than the air moving under the wing, so it creates an extremely low pressure area on top of the wing, lifting it upwards (perpendicular to the direction of airflow)


When air flows through your carb, it will create a suction through the passage that leads down into the bowl. The faster the air moves, the more suction you get. This suction will suck fuel from the bowl to mix with the airstream.

If your main jet is too big, this suction will suck too much fuel, causing it to run rich. To0 small a jet, and it will run lean, obviously.

It's not a simple case of "more air, so more fuel." You want to look at the difference in air velocity through the carb. A smaller carb will have have a higher air velocity, which will result in more suction from the bowl, so you need a smaller jet so you don't suck too much fuel. Larger carbs will have a slower air velocity, which results in less suction, so you need a larger jet to get all the fuel you need.

With a smaller carb, the engine has to

[Narly R]

Originally posted by XANDADA
Just out of curiousity, did you figure out why you fried the piston before. Thanks to Harry at Trinity I burned a hole in a banshee piston cause it was undercarb'd and runnin too lean on the top end.

Don't go givin up on the R yet:D

Well my dad got really bad gas like 87 octane and the guy at the bike shop gave us a mix bottle and said this much with 4 gallons for for 42:1 but I really mixed it like 50:1 so it was detinating and well I blew it up! But Im not going to give up on it! ;)

[Narly R]

wilkin250 thanks for the info I uderstand what u are saying !!! I see now!:)

[wilkin250r]

I'd try a race on a paved road, or at least hard-pack, while you still have the stock sprockets. I bet you leave your buddy sucking your exhaust until 6th gear. With a 350 and stock gearing, I bet you have a hard time keeping the front end on the ground until 3rd gear on a paved road.

[Narly R]

I rode on a paved rode and it would want to weelie like crazy! But Im shure I could beat him on pavement!:ermm:

[wilkin250r]

Originally posted by Narly R
I rode on a paved rode and it would want to weelie like crazy! But Im shure I could beat him on pavement!:ermm:

Yeah, I'd change the gearing if I were you, try the 14t front sprocket. For $20 it's an easy cheap fix, and it will definitly suit the powerband of the 350 much better. I hope your buddy likes looking at your rear end, because he will never be out in front of you again...

[Narly R]

Well Im not out to be the fastes guy! But i just want my engine to perform the way it should! But I might try the 14 tooth sprocket?! I just want it to run the way it should!:ermm:

[wilkin250r]

Originally posted by Narly R
Well Im not out to be the fastes guy! But i just want my engine to perform the way it should! But I might try the 14 tooth sprocket?! I just want it to run the way it should!:ermm:

This goes back to what I said earlier. The 350 will make way more power, but it won't rev as high. So you basically improved the bottom end significantly, and lost a little top end, so you need to gear a little taller to shift the power delivery back to where you need it. I bet you're just spinning the tires in first gear anyway.

With the 14t front sprocket, it won't be as easy to spin the rear tires on dirt and gravel, so I bet you actually GAIN acceleration because your tires will hook up better.

Do you have a 38 or a 39 on the rear?

[Narly R]

I have a 39 on the back. I race motor-cross so the 14 tooth front isnt for me but I could get one for the dunes and what-not,so i just need all the power I can get with my ranges without making it go to afully fast. It should run awsome or atleast A LOT better with the bigger carb!:ermm:

I have a Niks 330 kit with a 350 crank, so they had to put a spacer ibetween the cases and the head (if that matters) I think with it like that it takes it a little longer to rev but Like I said The carb better fix that!:scary:

[wilkin250r]

I don't race, so maybe this isn't worth much, but I would imagine that a 350 with stock gearing is way under-geared, even for motocross.

I'd take a buddy to the motocross track and get some lap times with different gearing setups, you may be suprised...

[Narly R]

Ya maybe but I dont think im going to be going over 70 on he trach will I? But Ill try both sprockets just to see!:ermm:

[powerslider]

You really need a big bore pipe, your Bills is not made for a 350 plus it's a low/mid pipe so it won't rev out on top compared to others. The big bore pipes have larger diameter stingers to properly flow the increased exhaust volume the 350 produces. The new carb won't help much with out the pipe, Sparks or LRD have the pipes. You need the silencer also as they have larger diameter pipe.

[Narly R]

I know I NEED a BB pipe but I just cant afford it right now but If I get some money (ya right) or maybe maybe (fingers crossed) get sponsered by this one company I be able to get a BB pipe Im going to get a LRD when it happens, that will prolly be a while though...:(