PDA

View Full Version : who has mess with FCR carbs?


cals400ex
03-25-2004, 02:00 PM
alright, i just purchased a used fcr dirtbike carb for the 400ex. i found the mainjet and pilot jet just fine. the fuel skrew is tucked up under the bowl a ways. i took the metal intake part of the carb off (it was off a dirtbike so this comes off) and i see a round, not hex, keihin 200 mainjet and an adjustable skrew. first, what is that mainjet doing there? 2nd, is that the air skrew? if it is, how are you suppose to adjust it without taking the intake part of the carb off? any assistance would be great. thanks, cal
pnut420
03-25-2004, 06:21 PM
Originally posted by cals400ex
alright, i just purchased a used fcr dirtbike carb for the 400ex. i found the mainjet and pilot jet just fine. the fuel skrew is tucked up under the bowl a ways. i took the metal intake part of the carb off (it was off a dirtbike so this comes off) and i see a round, not hex, keihin 200 mainjet and an adjustable skrew. first, what is that mainjet doing there? 2nd, is that the air skrew? if it is, how are you suppose to adjust it without taking the intake part of the carb off? any assistance would be great. thanks, cal

You can get to the fuel screw without taking the cover off. The CR part of the carb is the top, so when it is together look underneath it and you will see a small regular screw. Leave it where it is for now and just see how it runs. The scew you are talking about when you take the cover off is something else.

If you really need me to, I can take my brothers carb off and show you. Nothing removes any different because this was off a dirtbike, a FCR39 is a FCr39 for the most part. Hope this helps, if you have any questions you can always call me. ;)
cals400ex
03-26-2004, 01:20 AM
thanks for the help. basically, i am trying to figure out what that round jet and adjustable skrew does when you take the intake adaptor off? maybe its not a round keihin mainjet,but it sure looks like it. all i know is that it says 200 on it and it has the K for keihin. these have to be there for a purpose and that is my goal to figure out. i will probably install it tomorrow. thanks for the help.
MIKE400EX
03-26-2004, 08:16 AM
Looking into intake end of carb, the adj. screw on the left is the "slow air screw" & the one on the right is the "main air jet".
You have a PM.
cals400ex
03-26-2004, 11:53 AM
Originally posted by MIKE400EX
Looking into intake end of carb, the adj. screw on the left is the "slow air screw" & the one on the right is the "main air jet".
You have a PM.

thanks for the help. i would appreciate if you could get me those instructions on what these do or when you change them out, etc. any info would be fantastic.