dissapointed yet happy

[Out_Sider]

aight..today i was home sick from school, and i went outside to the garage to look over the 300. and i decided to take the 400ex carb off and try the stocker out w/ a 155 main and 42 pilot...and WOW!!! the stock carb is WAYYYYYYY better!!! i believe i got like a damn 15% power increase!! i was amazed! i was happy about the extra power, but highly dissapointed in the 400ex carbs performance..so far i have nothign good to say about that mod for a 300ex... im gonna be sellin the 400ex carb, and havin my stocker bored out. ;) just wanted to let some 300ex ppl out there know a lil somin, somin about this mod

[2k2-300exnj]

u may have lost some top end power

[muff]

did you even try adjusting the 400ex carb after throwin it on there? or did you assume the jetting and everything would magically be perfect to go from the 400 to the 300 motor?

[Sportrax10]

Originally posted by muff
did you even try adjusting the 400ex carb after throwin it on there? or did you assume the jetting and everything would magically be perfect to go from the 400 to the 300 motor?
Yea, I was thinking the 400ex carb might not be jetted right...

[Out_Sider]

i tried ALot of jets!! 135 all the up to 170..and pilots from 38-45..nothing worked..it never wanted to idle, and was sluggish up top..my stocker feels more powerful everywhere

[swamprider7]

the jets from 135-170 may have all been too rich for your motor. You should have tried some smaller jets.

[2k2-300exnj]

Originally posted by swamprider7
the jets from 135-170 may have all been too rich for your motor. You should have tried some smaller jets.
yea your running a 135 in your stocker the 400ex carb is a lot bigger try like a 127 and i bet it works awsome

[Toadz400]

Stupid people...think that they don't have to do anything and it should work perfectly fine going from a small motor to a bigger one. You definately should've tried smaller jets, it was retarded of you to try a 170 because even I don't run a 170 on my 400ex!

[dirtmomma]

Hummm this is a good thread since I'm getting ready to do the switch over to a 400 carb, I haven't done it yet but was talking to some fellow racers who did it on thier 300(VERY HAPPY W/ IT) & he was saying he had a 42/160 or something like that so I went & got a 150,155,165 :confused: I may be totally off here it sounds like. I'm @ about 500-1000' altitude also so maybe that it why he's running it so high. Come on lets get more suggestions here, what ARE you 300/400 carb convertors running for jetting???????????????????

[AndrewRRR]

They make jets that small? lol

[wilkin250r]

Bigger carbs are not always better. If they were, than every quad ever made would come with a 50mm carb. What they gain in top-end power, they lose in throttle response.

[dirtmomma]

Okk now you guys got me thinkin'!! So from what I'm reading on here it mainly gives you more TOP END??? Hummmm I may just want to stay w/ my stocker for short track racing then. BUT what if I get a cam,rockers, would it be better then???

[AndrewRRR]

Originally posted by dirtmomma
Okk now you guys got me thinkin'!! So from what I'm reading on here it mainly gives you more TOP END??? Hummmm I may just want to stay w/ my stocker for short track racing then. BUT what if I get a cam,rockers, would it be better then???

Most aftermarket cams have more lift and duration, again giving you more top end. All depends on where you want power in your RPM range.

[cals400ex]

by the way, nice excuse to miss school.

[Dunlap]

We put a 400ex carb on are 345cc 300ex and didn't like it. The stock card work alot better. We have the stock carb on all the 390cc kits we build for GNCC's also.

[2k2-300exnj]

that is interesting i would have thought the bigger carb was better for such a big kit

[dirtmomma]

Originally posted by 2k2-300exnj
that is interesting i would have thought the bigger carb was better for such a big kit


Hmmm me too but I guess it's true what they say bigger is not always better LOL

[AndrewRRR]

Originally posted by dirtmomma
Hmmm me too but I guess it's true what they say bigger is not always better LOL

All depends on how you "use" it. haha
I have a 40.5mm on my 350r and it pulls better on top than the 38mm A/S I had before, but I didn't gain any bottom end (if any I lost a little).

[dirtmomma]

Originally posted by AndrewRRR
All depends on how you "use" it. haha
I have a 40.5mm on my 350r and it pulls better on top than the 38mm A/S I had before, but I didn't gain any bottom end (if any I lost a little).

YES this is true LOL :o

I dont' think I'll be usingthe 400 carb right now cuz I'm more of a bottom end racer I guess. Maybe I'll save it for the big tracks who knows.

[Out_Sider]

Originally posted by Mickey Dunlap
We put a 400ex carb on are 345cc 300ex and didn't like it. The stock card work alot better. We have the stock carb on all the 390cc kits we build for GNCC's also.

see!! this man knows what he's talking about ;) And im running a 155 in my stock carb right now...i dono where u got 135 from...

and i have a 330 kit ;)