fcr

[silenpro]

i just installed a fcr carb 39 of a drz 400 e model. the quad only starts and runs if my gas is on prime. if i put it on the on position no gas gets to the carb. i notice a nipple of the acc pump one side has a hose but the other side looks open. should a hose go there?

[airmobile101]

You need to install new fuel petcock or modify your existing one.

[silenpro]

wich one do i need or how can i mod it

[airmobile101]

Well, you can just leave it in "prime" if you want. The stock petcock works off a vacuum, which you don't need anymore since your running that FCR carb. Your only gonna have one line total. that the one coming from the fuel tank going to the carb bowl. As for petcocks, I had a Blaster one laying around and it fit, so I used it. Im not sure on how to modify the stocker, but I heard it has been done.

[cataway]

all you really get from modding the stocker is that you get the reserve to work, which can be nice .
its really no big deal ,any time i even think i may run out of gas I'm going to carry more any way ,its not like rev gives you more gas,its just a nice warning device.

[silenpro]

What jet sizes should I run with lid on Kn and hmf slip on. Pilot main neddle and air screw. Thanks

[cataway]

with the lid on ? you may be able to go to a 140 mj but no bigger.
your really not going to get much hp with the lid on . take off the lid jet up to a 150 mj maybe even to a 160 ,other than that stay out of the water
for the PJ i would think a 45 and the leak jet a 35
do the o-ring mod on the AP

[quad97]

What size FCR would work well on a 470bb with cams, open air box, full yoshimura pipe? What jetting would be close for 2500 ft elevation? What make and model is best to get one from?

[silenpro]

What's the acc pump mod. With the oring?

[cataway]

Originally posted by quad97
What size FCR would work well on a 470bb with cams, open air box, full yoshimura pipe? What jetting would be close for 2500 ft elevation? What make and model is best to get one from?
a 39 should work very well ,and if you then felt you needed more
get it tapered bored to a 41 put on some thing like a RAT stack
then maybe an esr or even the 450 r boot the 400 ex boot is all so good .
jetting ,i would like to think that some thing close to what I'm running should get you close , the only way to really know is to get on a dyno with AF

if your looking for a used carb ,look at YFZ's, you will also need a cable and a different thumber ,you can get just the cable that will work with your stock thumber but it will end up costing you about $60.
the only other issue is the carb to head boot ,but napa can fix that with a short piece of gas hose.

[cataway]

Originally posted by silenpro
What's the acc pump mod. With the oring?
its just a way to hook the linkage together to get a quicker stronger squirt of gas . some guys have wired it some use a small o-ring ,i tired the o-ring ,ended up zip tyeing it

[silenpro]

what are you actually zipping ? do you have a pic. i just rode it for the first time with the carb. it pulls nice. if i am in any gear at 1/4 or mid throttle steady then full throttle it feels like i hit a wall then takes off like a bandit. is that the acc pump or jetting prob. thanks for the replies..

[cataway]

go here http://www.squadpage.com/pandora/Professor%20RedBeard450%20How-To%20AP%20Mod.pdf

under AP Mod 1 should be page 10

[cataway]

more good info http://www.thumperfaq.com/jetting.htm

[cataway]

Originally posted by silenpro
if i am in any gear at 1/4 or mid throttle steady then full throttle it feels like i hit a wall then takes off like a bandit. is that the acc pump or jetting prob. thanks for the replies..

sounds as tho you are experinsing what is called the bog .

in the bottem of the carb bowl there is a jet ,this jet should be changed to a #35, i had to plug mine but try a #35 first

[silenpro]

in the bowl itself or where the jets are. i notice it had what it looks like a FMF kit. main was a 136 pilot 45 and another one opposite 65. my carb is diff then the one in the pictures about the o ring mod. i have a plastic piece that moves this arm.

[cataway]

a 136 would seam to be a bit lean , the 45 should work .
dont tuch the 65 .
the leak jet is pictured on page 12 of http://www.squadpage.com/pandora/Professor%20RedBeard450%20How-To%20AP%20Mod.pdf


could you maybe get a pic of your carb ? just so that i know we are on the same page so to speek.

[silenpro]

k i will look tom, iam going to take pics and try to post them. kind of new to mac but il try. thank you for your help and time. appreciated. :) i did change the main to 142.

[silenpro]

i looked at the bowl and there is no leak jet. it only has a pipe coming out of it. i am up to 150 main and 2 turns out. it seems much better with no popping on decel but that bog is still there. not as bad but steady throttle to full is the only time it bogs. i can t get a pic of the carb but it came of a 2000 DRZ 400 E.

[silenpro]

i looked at the bowl and there is no leak jet. it only has a pipe coming out of it. i am up to 150 main and 2 turns out. it seems much better with no popping on decel but that bog is still there. not as bad but steady throttle to full is the only time it bogs. i can t get a pic of the carb but it came of a 2000 DRZ 400 E.

[cataway]

are you using some sort of spark arrester ?

[silenpro]

yea just the screen at the end. i had more time today to mess with it and finally the bog is gone. a 160 main did the trick. shes running insane. thank you for all your help.