I know this topic has been around before. I performed a search and read some of the past posts but it looked like it had been a few months and I would like some current opinions.

I just bought another highly modified 350X motor which is bored and stroked to 500cc from Ebay. I need to purchase a carb for this motor and am looking for input on which carb to buy. The FCR seems to be the most popular choice for modified 440EX motors. I am also considering the 40mm Lectron and have read the comments about the lack of an accelerator pump. The dual carbs on my current 500cc motor do not have an accelerator pump and there is absolutely no hesitation at the crack of the throttle so I don't know if this is a real problem or not. And TC Racing uses the Lectron almost exclusively and they are one of the top 4-stroke builders in the country.

If you own a FCR carb please let me know what you think about it. Does this carb offer low and mid-range performance or only top end? What about jetting and tuning? Is the motor harder to start with this carb? Any input would be appreciated.

 

Took some tinkering to get a bottom end bog out of it when the throttle is snapped open, but I'm there. Starts as easy or easier than stock (rejetted). Gained performance everywhere, especially bottom and mid (contrary to what logic would tell you on a larger carb), don't think I have enough cam to get much more out of the top. Fuel economy doesn't seem to have suffered much, but can't tell for sure, have only raced with it (cross country) and done a little play riding.

One of the best features is that it fits nicely on the 400EX and doesn't require any modification to anything, just get a throttle cable and go.

It's a very high quality unit with a fairly light throttle pull.

Currently running 3rd pos on the needle, 172 main and a 52 pilot with accelerator pump mods.

 

Thanks for the reply Gabe, informative and to the point as usual. I have made up my mind to go with the FCR. I just saw this weekend that the KTM 520 4-stroke MX dirtbike even comes from the factory with the 39mm FCR, it is definately the carb of choice for performance 4-strokes.

 

As does the YZ250F (37mm I believe), YZ426F, the DRZ400, the list goes on and on....

I wasn't too terribly impressed when dialing it in at first, but then I stuck the stock carb back on for grins, and the difference was quite apparent. The FCR was much stronger everywhere.