fcr37 jetting bogs when quick rev

[dmaheryfz450]

hello guys i new to the forum i have a 400ex my problem is its bogging when you just cruise and then pinn the throttle it wont take it it bogs then it pick up im running crf450 chain air box lid on or if i remove it it makes no difference that i can tell it has a car filter thats alot bigger fmf pipe keihin fcr37 carb 175main and 50pilot fuel screw 2 turns out and choke removed any help appreciated thanks oh by the way there only about 40 hrs on fresh top end it was only bored slightly .20 over or something but in a high gear it runs real good but still feel sluggish when you give it a quick rev please help it driving me :mad: heres a pic of it tell me what you think

[HondaRacing83]

nice bike

[dmaheryfz450]

thanks buddy any idea what wrong with it

[sneaky11]

I have a 400ex with fcr40mm carb, and had the same problem... the problem with fcr conversion is the leak jet, try to switch it up for a bigger one to make u run a little bit leaner ... i'm not gonna give u a course on leak jet... there'S a bunch of info on that if u search a little bit on the internet.... personnaly i buy a ATHENA DUAL SPRAY VENTURI JET KIT( great great stuff but I really not recommand it to u if ure a not skilled in carburation its tricky to install and u can bust ure carb) with an ajustable leak jet from R&D ( that is what i recommand)... u can just get one or the other or just go for buying some leak jet and tuning ure carb perfectly... maybe its not that but sounds like!! Good luck!!

[IRISH-RACER-14]

Welcome fello irish guy :)

[IRISH-RACER-14]

Welcome fello irish guy :)

[flyboy1294]

Originally posted by dmaheryfz450
hello guys i new to the forum i have a 400ex my problem is its bogging when you just cruise and then pinn the throttle it wont take it it bogs then it pick up im running crf450 chain air box lid on or if i remove it it makes no difference that i can tell it has a car filter thats alot bigger fmf pipe keihin fcr37 carb 175main and 50pilot fuel screw 2 turns out and choke removed any help appreciated thanks oh by the way there only about 40 hrs on fresh top end it was only bored slightly .20 over or something but in a high gear it runs real good but still feel sluggish when you give it a quick rev please help it driving me :mad: heres a pic of it tell me what you think

1st, give us a list of engine mods, please. It sounds like your main is rich.

2nd, did you make a video of that bike and put it on Youtube? I'm pretty sure it looks familiar... the owner of said bike was talking about how it looked like a Yami? :eek2:

[dmaheryfz450]

thanks guys it is one youtube i did make it look like a yamaha but i love the 250r style front fender

[IRISH-RACER-14]

Originally posted by dmaheryfz450
thanks guys it is one youtube i did make it look like a yamaha but i love the 250r style front fender

you give honda owners a bad name.. lol

[dmaheryfz450]

Originally posted by IRISH-RACER-14
you give honda owners a bad name.. lol haha lol

[4reeds]

Mine is a 416 with highcompression piston and fcr39.I run a 172main, i believe it was a 55 pilot and 2 1/4 turns.If that is any help.Lid off.

[dmaheryfz450]

thanks buddy it driving me crazy :mad: