Fcr jets?

[junior636]

This may be a dumb question but do I need to buy jets specific to the fcr carb and if so where do I get them? I just bought a 400 and switched from the 416 to the 440. I don't know anything about this carb. I am just assuming I am going to need to re-jet.

[CJM]

Your sure its an FCR carb? A 400ex unless switched by someone should have a keihin type carb.

This is an FCR carbhttp://img261.imageshack.us/img261/147/fcr1dp3.jpg

This is a keihin 400ex carb
http://cf.mp-cdn.net/51/38/68736952b77b50905c9448bca3e7.jpg

[junior636]

Yes absolutely sure it's an fcr.

[junior636]

The quad came with two motors and the fcr on it. I also have the stock carb and a flat slide that doesn't use jets a lectron or something like that. So I'm positive it's the fcr. I just haven't used one of these carbs before so I wasn't sure if they required a special jet or anything.

[NacsMXer]

Originally posted by junior636
Yes absolutely sure it's an fcr.

You first need to determine what type of FCR carb you have because the two main types of FCR carbs take different jets. Did the carb come off of another bike?

Jets R Us is where many get their jets from. If you visit the page below you will notice there are two different links for FCR carbs; FCR MX and FCR horizontal/downdraft.

Jets R Us (http://www.jetsrus.com/a_jets_by_carburetor_type/a_jet_kits_keihin_selection.htm)

[junior636]

Its an fcr 39. Do do I need to get jets from there site or something?

[NacsMXer]

Does it look like the FCR CJM posted or this one?

FCR CJM posted is FCR MX style. The one i'm posting is the horizontal/downdraft/slant body/aftermarket/"Sparks/Sudco" style.

If you're unsure, just give jets r us a call and they can set you straight.

http://i305.photobucket.com/albums/nn214/jomore8/fcr002.jpg

[junior636]

Its the same as the one you just posted not the first one.

[junior636]

I just read the for sale ad (bought the quad off from here) says it's a 41mm FCR and I'm sure it's the one posted above.

[NacsMXer]

Ok, what you have is an aftermarket FCR. Horizontal,downdraft,slant body, side draft, Sudco style, are other nicknames for this style of FCR carb. The FCR 41 you have is a very nice unit.

It takes regular Keihin hex style main jets, the series of jet is 99101-357. It takes a special Keihin pilot jet, series N424-25B. You can buy them off jets r us, or if you want to try your dealer, just give them the series of jet and the size you need.

You're also going to want to get an extended fuel/pilot screw to fine tune your pilot circuit with the carb installed and the engine running. Most of them these days are designed for the FCR MX, and will require you to make the hole in the float bowl the screw passes through larger. A light pass with a drill bit works fine. A R&D Flex jet is another great option. Requires no mods and allows for complete remote adjustment.
http://www.motorcycle-superstore.com/2/10/215/18720/DPITEM/Dirt-Bike-Motocross-Fuel-Mixture-Screws-R-D-Racing-Flex-Jet-Remote-Fuel-Screw.aspx

[junior636]

Thanks for the help I really appreciate it! This is my first quad in about 8 years so I haven't followed this stuff in awhile, just trying to re-learn it all...

[NacsMXer]

No problem, good luck with the new quad. And welcome to the site! :macho

[junior636]

Ok, so I am still having problems with this carb. Seems something keeps clogging the accelerator pump. I cleaned it and blew it out with air and it ran but then clogged again, and again, and...again. The back side of the diaphragm was quite dirty and is rusty, all I can think of is that somehow its worn and pulling dirt from the back side. I know this shouldn't happen but I don't know what else it could be at this point. Once the carb has gas in it the accelerator pump doesn't function anymore. So I was just going to buy a new diaphragm and springs that actuate the pump. Can anyone tell me where to buy parts for this carb? It is the aftermarket FCR 39, guy I bought it from said it was a 41mm. Thanks for any help guys. After two weeks of working on my brother in laws new KTM I am ready to get mine going now...

[NacsMXer]

www.sudco.com

They can get you the parts you need and are quite knowledgeable when it comes to FCR's.

[junior636]

Thanks for the link! I will have to call and talk to those guys and see if they can help me. I got the stock carb with the quad too so I just went through that tonight and got it running. I have had this thing for a month now and rode it about 10 mins. I just want to go to the track already!