any do the fcr accel. pump mod?

[cals400ex]

i was just wondering if anyone did the fcr accel pump mod? i reduced the squirt to about .5 to 1.0 seconds. i don't have a bog anywhere. however, i think the accel pump was covering up the other jets. i would constantly get a black plug before. now my plug is a normal to a lean color. i realize your suppose to tune the carb in without the accel. pump hooked up but i haven't got around to doing that yet. just wondering if anyone has had good success with this or not? thanks

[cals400ex]

i assume not too many people have done this. :D

[Doibugu2]

it sounded kind of complicated. Did it take you long?

Where did you get that 1 piece from. The wheel axle nut or whatever it was called.

[Quadzilla]

What jet sizes are u running?
Main?
Needle?
Pilot?
Needle clip position?

Also, what kind of motor?
Piston size/compression?
Cam?

[cals400ex]

Originally posted by Doibugu2
it sounded kind of complicated. Did it take you long?

Where did you get that 1 piece from. The wheel axle nut or whatever it was called.



the mod really didn't take too long. i actually couldn't get this block connector or rc wheel collar at radio shack, napa auto parts, or ACE hardware. i just couldn't find it. however, a while back i was into gas powered rc cars. so, i had a few pieces that would work good. however, they just weren't the 2/32 size. all i had to do is drill the connector out to that size and it worked great. i did notice that my fuel ratio did lean out quite a bit.

[cals400ex]

Originally posted by Quadzilla
What jet sizes are u running?
Main?
Needle?
Pilot?
Needle clip position?

Also, what kind of motor?
Piston size/compression?
Cam?



406 10.8:1 ross piston, x-6 pipe, stage 2 cam, modded airbox lid, uni filter, and the fcr 39.
70 degrees outside at 625 feet above sea level.

162 main, emr needle with clip on 3rd position, 50 pilot

i have a emp and 1 other needle on order along with the adjustable fuel skrew.


however, i just don't think i got an major power gains out of this carb. i gained only about 1 bike length in a drag up to fifth gear. so maybe the jetting is wrong or something. i did gain good throttle response though. i want to clarify that i don't have a low end bog anymore. however, if i quickly stab the throttle from a stop it still wants to stall. hopefully i can get that fixed when i get the adjustable fuel skrew in.

[Quadzilla]

You may be a little lean on the main and needle. Try a 170 main and lower the needle by 1 and see what happens. Please report back to us.

[nakomis0]

Cal you ever try and find a dyno w/ a sniffer in your area? Its should be decently priced like $30 a half hour... in reality you'll probably take an hr. $60 .

I have spend alot of hours jetting my quad, and it ran good... but then I take it to a dyno and they find 3-4 hp just in jetting in an hour.

I'll doubt I'll ever try and jet any of my modded machines by myself again.i

[Chef]

Originally posted by nakomis0
Cal you ever try and find a dyno w/ a sniffer in your area? Its should be decently priced like $30 a half hour... in reality you'll probably take an hr. $60 .

I have spend alot of hours jetting my quad, and it ran good... but then I take it to a dyno and they find 3-4 hp just in jetting in an hour.

I'll doubt I'll ever try and jet any of my modded machines by myself again.i

Are those dynos with a sniffer pretty common? I would like to put my EX on it just to see how much more there is in the jetting.

[nakomis0]

I haven't looked very hard, but I know of 2 within 15-30 miles of me. Granted I live in a heavily populated area.

And every dyno I have seen has had the sniffer. Its a little unit thats seprate from the dyno, so I suppose its possible to just find a sniffer hooked to a computer, that would give you fuel/air ratios, but not hp numbers.

[cals400ex]

i would love to find a dyno in my area. however, i only know of places that dyno cars around here ( and they are NOT cheap). i would like to find some other place anyways so they have some idea about the carb i want tuned.


quadzilla, sparks and powroll told me to run a 165. i will try them out. also, i haven't been able to check my jetting too much since i modded my accel pump. i will try to get this done friday. also, i ordered two new needles for the carb that sparks, C&D, and gt thunder told me to try. so, i probably won't mess with the needle until those come in. i know i am fairly close on the needle setting by how my plug looks at 1/8 to 3/4 throttle. however, i will mess with it when the needles come in.

[Quadzilla]

What needles did u order?

[cals400ex]

Originally posted by Quadzilla
What needles did u order?


EMP and OCEMN

[cals400ex]

Originally posted by Quadzilla
You may be a little lean on the main and needle. Try a 170 main and lower the needle by 1 and see what happens. Please report back to us.



well i did some plug chops today. i currently am running a 406 at 10.8:1, stage 2, x-6, modded airbox lid, uni, and the fcr 39mm.

my jetting right now is 162 main, 200 main air jet, 2 turns out on air skrew, 2.5 turns out on fuel skrew, 50 pilot, stock needle in stock clip location.

my plug looked good at idle, 1/10, 1/4, 1/2, 3/4 and full thorttle. basically, it wasn't black or white in any of the places. i think it is jetted fairly close. i messed with the accel pump again and right now i have it set so it shoots gas for 2.5 seconds. i do think that is a little much but i haven't tuned it down yet. i will try larger mainjets and see what happens. i am just never in favor of the large mainjets since that usually hurts the top speed. we will see though.

[Quadzilla]

Good info. Keep it coming. Yes, 2.5 seconds is wwway too long. Should be LESS than one second!

[cals400ex]

Originally posted by Quadzilla
Good info. Keep it coming. Yes, 2.5 seconds is wwway too long. Should be LESS than one second!

see, when i adjust it less than 1 second, it really doesn't squirt out. it just squirts a foot or so max. it seems like more of a dribble. we will see though.

[dork]

i found on my yzf 400 when i was about .5 second on the pump duration that it was a bit too little for the cold weather. it seemed to like about 1-1.5 seconds. but now that its warmer, its back to about .75-1 second. you should definitely check out thumpertalk.com and go in the yz or wr forums and do a search on accel. pump mods and pilot air screw adjustments, there's alot of info. remember though, on the FCR2's , which were on the 00 and up 426's, the jet numbers will be lower than on the original FCR. i think they redesinged the internals which allowed them to run slightly leaner jets.


however, i just don't think i got an major power gains out of this carb. i gained only about 1 bike length in a drag up to fifth gear. so maybe the jetting is wrong or something.
i thought the main advantage of these carbs was in throttle response and tuneability, not peak horsepower. it also seems that on any of these carbs, whether the FCR or FCR2, if you really snap the throttle open as fast as you can from an idle, they will stall. if you run your idle a little higher though, it seems to help.

heres a chart that shows the pilot air screw turns and their fixed air jet equivalents chart (http://www.msnusers.com/fcr39s/shoebox.msnw?action=ShowPhoto&PhotoID=3)