400ex carb on FST330ex.

[bwamos]

Well last weekend I installed my new (new to me) 38mm 400ex carburator on my 330ex.

Just for informational purposes.
I ended up with my jetting at:
42 pilot, 2 turns out.
Needle in 3rd slot
160 Main Jet.

Jetting is kinda finiky, but makes it easier IMHO.. lol. 155 bogged, 165 spits. aka 160.. lol. Needle, same deal. Pilot, stock 38 would only idle at 2.5+ turns out.. and would idle a LOT faster w/ choke on slightly. Aka.. needs a 42.

Holy cow does that carb make a difference. Haven't been able to ride test it yet (that will be next weekend), but it sure makes it run a lot better. You can hear and feel the difference.

I also have a 350x air boot. Not sure how you guys get that thing to work. Doesn't fit up well. Carb side is no larger than the 300ex boot.. plus the boot is angled up, so when you push it down it isn't square to the carb and the lower lip want's to pull away form the carb.

Perhaps I have an air boot from the wrong year 350x?

[bradley300]

i also had a 350x air boot, and couldnt get it to work on a stock 400ex carb. i was able to strech the stock 300ex boot onto the carb tho.

[bwamos]

Aye, that's what I did. Used the old heatshrink heat gun to soften it up a bit, then stretched her right over and clamped it down.

When making adjsutments, I just detatched the boot at the airbox and left the boot on the carb. Easier, then trying to get the stocker back on every time. ;)

My only problems while tuning it was that, my reverse switch re-oxidized on me again, (put some dielectric grease in there this time) and it was bouncing of the rev limiter at about 3500rpm. I was like... what the heck.. that's not normal... then it dawned on me. Nothing like convienient timing for something to mess with my head. Luckily it only took me about 5min to wise up.. lol.

[Ryanwolfe911]

That's precisely why I elimnated mine. Besides, i like being able to go 30MPH in reverse. LOL

[bwamos]

I'll occasionally have 10-12 yr old kids on it.. so I have tried to maintain the "saftey" devices to keep them from going 30mph in reverse.. lol. If it were just me, I would have bypassed it, along with the reverse button on the clutch, long ago. I also have a remote kill switch. ;)

[rooster300ex]

Would a 400ex carb benefit me any with my mods.

[bwamos]

Borderline.. but it should definatly help. May be a little trickier to get it tuned. Lower air speeds (less volume per cycle).

I used to have a 34mm mikuni flat slide on my 300 when it was near stock. Pipe/Filter/Jet. It definatly made a difference up top. My buddy and I had near identical atvs back then. Drags were side by side. Finishes were within inches. Adding the carb changed that I was finishing a quad lenght or 2 ahead. (basically fan up to the rev limiter faster) Bad carb choice though. Didn't have an accelerator pump. Took it off. Now I know better.. lol.

The on;y thing that diesnt fitup well on the 400ex carb is the intake boot. The Outside diameter of the boot.. is about the same size as the flange it has to slip over. Needless to say theres a lot of stretching to do.. lol.

IMHO.. you'll get a lot more power out of a better pipe. ;) Your killing yourself with that Cobra.

No point drawing more air in if you can't get it out. ;)

[rooster300ex]

If I ever get another pipe its gonna be a curtis sparks. Until then i'll be alright with what I got. Them sparks pipes are pricey but worth every penny. so i've heard. I know cobra's arent' the best, but my seems to flow damn near like straight pipe. To me that would be the more flowing pipe.

[2muchquad]

I know cobra's arent' the best, but my seems to flow damn near like straight pipe. To me that would be the more flowing pipe.

A cobra will flow more than stock and actually run better if its rejetted(your motor anyhow) accordingly,regardless of what you read,the cobra isnt that bad,just on the loud side though,but so is a TC and its $300.:eek2:

[bwamos]

Sparks X-4 is between $350-$400 depending on wich options you get. They aren't as expensive as some seem to think. The HMF full system is more expensive.

Supertrapp, and Pro-Circuit are about the same price. Yoshimura is more expensive.. etc..

The 300ex is a little different on the pipes because it's a 19yr old model ('87 250x). The normally cheaper pipes are more expensive, and the older brands of the more expensive pipes are a less. (yosh excluded, they're always expensive.. lol).

[rebelbuggy]

Originally posted by Ryanwolfe911
That's precisely why I elimnated mine. Besides, i like being able to go 30MPH in reverse. LOL

what the heck is a reverse switch? Is that built into the stock cluth levers and all? if so I dont have one anymore cause I took my stuff off and puting a regular cluth lever on it..

[Sjorge450R]

hey bwamos, can I just straight throw a 400ex carb on?

[rebelbuggy]

Originally posted by Sjorge300EX
hey bwamos, can I just straight throw a 400ex carb on?

I just put a 400ex carb on my 300ex, and I didnt have any problems getting it to go on the motor, but the one from the back of the carb to the airbox is really tight, I got to get a longer screw for the clamp cause it wont go right now...

but it works, it runs with it, Cant drive it cause still waiting on my bearing carrier and stuff