Going from fcr1 to fcr2 on wr400

i wanted to update my wr400 carb to the fcr2, the one with the red hot start button, due to issues breaking the valve float 3 times. i should have done this a year ago....

anyway for ebay purposes the fcr2 was stock on which models? 2002+ yz426 right? what about other makes, like crf's and ktm's?

anyone have a fcr2 to sell??? thanks in advance.

Forget the FCR carbs. After breaking two slide plates and not being able to get a decent idle, I changed to an Edlebrock Quicksilver carb and it works fantastic - better than the FCR ever worked, and you can adjust the jetting by turning a screw on the top of the carb.

get a yz fcr2 carb..a wr fcr2 carb has gt the air-cut valve which usually mess wif ur idle..i'm using a yz426 carb on my 98 wr400f.. to me there a slight bottom end gained compared to fcr1 carb.. cheers

They started putting the FCR2 on the WRs in 2000.

I put an FCR3 off of an '04 WR450 on my '99 and it has been working great. The air cut valving doesn't bother me and I think it helps with off-throttle burbling and popping. I got it on eBay for $295.

The FCR3 also has the handlebar-mounted remote hot start. Very convenient.

I've never heard of the Edlebrock Quicksilver carb. Has anyone else tried it with good results?

alright, looks like i've got a couple options:

1) edelbrock. looks cool but i'm broke, so that's out.

2) fcr2. still a decent option but none on ebay right now, so i still want one if someone has one.

3) cnc'd valve float plate. some of the singapore riders are using these as a solution to the broken valve plates, and one guy who was really nice mailed me one for free. most report good results but i've heard one case where it didn't break but it dug out the carb. that still seems like a better risk than having to tear my engine apart AGAIN fetching out broken carb pieces. any feedback here on those plates?

They started putting the FCR2 on the WRs in 2000.

I put an FCR3 off of an '04 WR450 on my '99 and it has been working great. The air cut valving doesn't bother me and I think it helps with off-throttle burbling and popping. I got it on eBay for $295.

The FCR3 also has the handlebar-mounted remote hot start. Very convenient.

I wonder if i have the yz carb on my wr? it idles great, it acclerates nicely, but maintaining a constant speed in traffic is a pain in the ass. my spark plug looked great so jetting isn't a issue. if i'm just cruising at 30ish it feels like it surges/miss fires, ie difficult to cruise smoothly. isn't a problem at the track at all or while idling, just while riding casually. any ideas there? does that have something to do with the air cut valving?

The surge/miss problem is well documented with the WR400/426. For the most part, it's just something you will have to get used to. I don't think it's an air cut valve issue because I had my original carb "deoctopussed" (air cut valving removed and jetting compensated) and it still did it, although not as bad as a friend with a 426 who hasn't deoctopussed. Needle height adjustment may reduce the problem but can't fix it completely. I noticed with my old carb that the height of the needle would change the speed at which the miss/surge would occur but not eliminate it. Mine usually would do it at around 50-55 mph in 5th gear.

Keep in mind that these are basically racing bikes and are meant to be either accelerating or braking at all times.

at constant speeds, the TPS will cause the bike to surge, if you disconnect it will go away, previous suggestions have been to disconnect it for road riding and reconnect it for the dirt.

some people have even installed an inline switch, although you must shut down the bike and restart before switchinh the TPS back on. you can switch it off with the bike running.

cheers - Brett

wow, great input guys. i'm always amazed at the amount of knowledge here.

i've got a extra fcr1 that appears to be "deoctopussed". i think i'll try that carb out, put in the cnc'd slide, and disconect the tps. see where that gets me.

3) cnc'd valve float plate. some of the singapore riders are using these as a solution to the broken valve plates, and one guy who was really nice mailed me one for free. most report good results but i've heard one case where it didn't break but it dug out the carb. that still seems like a better risk than having to tear my engine apart AGAIN fetching out broken carb pieces. any feedback here on those plates?

Could you tell me which material was it made of?

presume aluminium

i've cnc'ed my own valve plate using aluminium.. i've used it for almost 2 years b4 i switched to a yz426 fcr2 carb.. stock valve plate oni lasted lees then 4 months for me..from my opinion the 2 half cresent indentation on the stock valve plate is where the weak spot is.. wat i did is to machined the exact spec but wif out the 2 half cresents.. so ur plate will be flat but stronger.. n the part where romours say dat dis valve plate will dig ur carb housing is totally untrue coz the plate is definately made of softer material then the carb housing..

look for aremean troy (TT Bronze member) coz he gt loads of these aluminium valve plates.. most of my wr riding buddies gt it from him.. cheers~

by the way stock valve plate is also made of aluminium, anodised black..

alright put the new cnc'd slide in and disconnected the tps.

1) tps disconected. WOW. i can actually ride smoothly down the street.

2) the other change i noticed is that it's now popping loudly on decel. ie too lean. my question is, would the tps have anything to do with that, or did the new plate somehow lean out the bike a bit? should i compensate with the fuel mixture screw, the needle, or the main jet??? besides popping, bike feels pretty good. Thanks!

im glad the stutter has gone

the popping on decel has to do with the pilot circuit

try adjusting the fuel screw if no help, go up a size on the pilot i think stock is 45. try 48

i had a similar problem with my 99, 48 pilot helped

i dont think the tps has to do with being lean/rich, more of the ignition timing

id say the cnc ed plate is the culpret

by the way, whered u get your cnc.ed plate from?? any pics?

cheers - Brett

try turning out ur fuel screw more n check how many turns.. if it's more then 3 n a half turns, u have to go 1 size bigger on ur pilot jet..oso check ur needle clip position too.. lean pilot n needle position will cause ur bike to pop on deceleration..

i'm trying to adjust the fuel, but i can't find me short tiny screwdriver! i feel like an idiot, been trying a day now just to adjust the damm thing without pulling the carb. it's around here somewhere..... i'll just figure out a way to richin it up. i'll hit the fuel screw, then the needle, then go buy a new pilot.

the cnc plate came from a singapore supermoto rider. those plates are really popular there. there's a pic on supermoto junkie, but i don't know how to attach on this site. looks just like the stocker except allum (not black) and doens't have the half moon cut outs.

wat u can do is loosen those manifolds on ur carb n tilt the carb sideway..

n yes those r the popular cnc plate which most of the 98 wr400f riders in singapore use.. very reliable n so far no such encounters of those plates breaking..

alright guys....

when i adjust the fuel screw so that the bike runs the best, that's when it pops the worst on decel. if i back the fuel screw out so that it doesn't pop, the bike runs the worse.

i take it this means i need to go up one pilot size? although i've had the carb apart plenty i didn't see where to adjust the needle height. do you raise the needle by backing out the screw on top of the slide? i'm ALMOST THERE!

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