FCR questions

[78ta]

I just installed a 39mm FCR on my built stroker motor. It appears to be some sort of conversion carb. It doesn't have a choke or hot start setup....not even drilled for them. Pretty much just bolted on, only needed to move airbox 3/4" forward.

I started it up and seems to run pretty good...except for it cuts out and dies when you snap the throttle wo.

Do they make an adjustable accelorator pump kit for these? I'm new to the fcr.

for the record, its a 460 hotrods kit, ported head, +1mm valves, hotcam stage 1, dmc dual exhaust, k&n lid. I'm currently running a 180 main and a 52 pilot 2 turns out.

for one you need to go with a stage 2 or 3 cam. when i put that carb on my 440 high comp. i had to change the jets. it came with 42/190 i think now its at 50/155 to 50/160

[4reeds]

I had to go to 55/168. Check your slow jet and f/s. I think mine is 2 3/4 turns

[NacsMXer]

I have that same carb on mine but with the stage 3 cam. My motor mods are below.

Here's my current jetting:

Pilot: 55
Fuel screw: 2 turns out
Needle: OCEMP needle middle/4th notch
Main: 175

I would suggest taking the intake bell off the carb and double check the main air jet, and air screw settings. There are 2 allen head screws holding it to the carb. Once off, you will see the main air jet and air screw.

The main air jet should be size 200, and the air screw next to it should be 2 to 2 1/4 turns out from seated.

[drew416ex]

I also agree you need a stage 3. I am running a 200 main, and a 52 pilot in my 440 stroker so youre prob lean on the main. they do make an adjustable pump but they are expensive. If you get your jetting dialed in you wont need to adjust it.

[78ta]

k running a little better now...got to checking things out today and had a fuel leak, right at the accelerator pump. seems to have been missing an o-ring. fixed that and now get a good strong squirt. not nearly as bad of a hesitation now. Still falls on its face a bit if you wack the throttle wide open fast with no load on it, but not bad when riding it.

I checked the main air jet, it is a 200 and set the screw to 2 1/4 turns out. What does this jet and screw control?

I need to start messing with the main jet, I pulled the k&n lid off and ran it and it is noticeably lean. The pilot seems close and fuel screw seems close too. 2 turns out and not running to bad down low and starts and idles good. I need to get a remote fuel screw for the thing bc its impossible to get to on the quad and running.

One thing I did notice is that this carb doesn't have the leak jet thingy in the bowl. just a hole no changeable jet so I guess the acc pump is not gonna be adjustable on this carb? Think an adjustable leak jet ***. would help me out?

[78ta]

stage 3 cam? yea that would be nice but unless somebody wants to give me one it aint gonna happen. No $$$ left lol. The stage one works good though it pulls super strong right off the bottom and through the middle. 3rd gear power wheelie almost from idle! Thats what I wanted anyway, I'm more of a woods rider and rarely get anywhere near the rev limiter so more power up top and less down low would kinda be a waste where I ride.

I'm gonna start messing with the main 2 morrow. I'm gonna keep going up in size until its super fat and then back it down from there. I'm gonna leave the pilot alone until I can get remote fuel screw and tune on it. I will mess with the needle once I get the main dialed in.