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View Full Version : got it all together, pics. (FCR)



maddmatt02
05-10-2007, 11:16 PM
well, I got it all together and plastics back on.

I got a 39mm FCR in there now, in the one pic, its an aluminum plate shaped to sit on the o ring, then a fitting with a slight flange, and the outer aluminum plate clamps the pvc to the first plate, and air box goes to the pvc, it will recieve the flo commander one day but didnt want to drop another 150 bucks right now, so this will do for the upcoming trip to reedsport, OR.

I also installed a new steering stem and bars since I bent em during race season. put on soem tall bars cuz Im standing about 95% of the time im riding out in the dunes.

dirt tires just on to ride around and play with jetting this weekend(front tires look wrong to me but the directional arrows say its right)


I bought a used YFZ thumbthrottle/cable setup to work with the carb, and I did like the "yamaha" badge on the thumb throttle so I ground it off and sanded it down from 180-1000 grit and polished it, needed to bleed the brakes anyways so I took the resorvoir cap off and grinded it down til the embossed warning label was gone and did the same.

to clear the carb I got longer bolts and spaced the tank up about 1/4" but it makes the seat sit oddly and the fuel shutoff isnt centered in the hole anymore, so i think Im gonna do the heatgun trick and push in the bottom of the tank in a bit.

also it runs good but if you stab it it wants to die, kinda like the YFZ does, but alot worse. I ran it at 52/180 and it ran decent but really rich and klinda sputtered when you nailed it, jets hadnt gotten here yet so I dropped it to 42/168 which is what I had and now it bogs bad when you nail it andf pops alot, so now its lean. jets got here this afternoon though and Im playing with it this sunday when I take it to a buddy of mines property.

feels pretty strong though just riding around the ~400 sq. ft. back yard.

hopefully Ill do good down there, racing my girls 04 YFZ-DRD/K&N/1Tdown. that was my main goal, another guy just got a 07 though, full gytr titanium system, K&N, stock gearing I think but hes got skat trak edges. I got geckos, I was gonna buy some extremes, but rockymountainatv is sold out of all the 21's and 22's, and in the 20's for a 10" wheel only 10 paddles, I wanted the 7 or maybe 9 paddle but both sold out... so geckos will be what Ill be running, at least my girlfriends has sand sharks. her dads raptor worries me now also, didnt before but hes got a +2 swing arm and skattrak 10 paddle edges.

her dad has some pounds on me though, and the other guy has even more on me.

DF400ex
05-10-2007, 11:17 PM
pics?

maddmatt02
05-10-2007, 11:20 PM
also port matched the intake manifold and modified the air box, was gonna try and get rid of it all together, but the carb mounting is untested, so I wanted as much support for the whole intake system as I could get, so I removed a lot of material but made sure to leave any contoured parts to keep it rigid. also left the bottom closed to keep some sort of protection (although not much at all)

http://i164.photobucket.com/albums/u9/maddmatt02/DSC00006.jpg http://i164.photobucket.com/albums/u9/maddmatt02/DSC00008.jpg http://i164.photobucket.com/albums/u9/maddmatt02/DSC00009.jpg http://i164.photobucket.com/albums/u9/maddmatt02/DSC00003.jpg http://i164.photobucket.com/albums/u9/maddmatt02/DSC00004.jpg

maddmatt02
05-10-2007, 11:24 PM
man youre quick, didnt take me that long....
also they are bad pics cuz its from a phone.

Dill
05-11-2007, 07:10 AM
for the off idle stab bog, you might want to try a #35 leak jet. When I got mine, the parts fiche didn't show them for the YFZ, but it did for the WR250 (same jet)

I would get a 30, 35, and 40 to try. The leakjet is the one located IN the float bowl, you can find it by following the passage from the accel. pump.

It seems this conversion isn't as easy as many people here make it out to be.

maddmatt02
05-11-2007, 07:55 AM
wasnt too bad, if Id have bought a crf/yfz's fcr it would have already had a flange to mount the air box boot on, and with the one I got, the stock yamaha peice is 10 bucks however no yamaha dealers stock it and all 3 of their dist. warehouses are backordered. thumb throttle assy. and cable I got for 20 bucks. didnt work perfect cuz the dirt bike cable goes in and recesses more than on the YFZ, so once again a YFZ's fcr would have been easier.

I was actually thinking of doing what they did at thumpertalk(where I read about it, Im sure lots of people know about it) drop a small ball from a bearing in and reinstall leak jet and this plugs the leak jet and then you tap a hole below the accel pump linkage and install an adjustable limiting screw to tune the duration of the squirt, an use the timing screw to adjust the timing. might actually do it today after work if I got time so I can play with that adjustment this sunday also.

so it doesnt sound like a possible jetting problem to you either? Im gonna take out my leak jet and see what size it is.

fitting the carb was easy, fit right in the stock manifold boot, just need a bigger clamp cuz at max the stck one doesnt open far enough.

Dill
05-11-2007, 10:45 AM
I have a YFZ FCR lined up for mine, my bike is mainly stock but I like FCR's over the lame vacuum operated carbs. It's nice to know it slid right into the stock intake boot.

The leak jet was an easy fix on my YFZ, some people report the Boyesen quickshot cover does the same thing, but I'll take a 4 dollar leak jet over a 90 dollar cover any day.

maddmatt02
05-11-2007, 07:58 PM
yeah, I might buy a few leak jets, i also bought a 6-32 screw, washers and stole a spring from a pen to do the bk mod so I can adjust the duration. Im gonna break out the heat gun and push the tank in a bit also, I dont like the shutoff being offcentered from its cutout, looks bad especially when I know its a simple fix.

feelthisroost11
05-12-2007, 04:26 PM
so a yfz 450 carb will work on a 400ex?

maddmatt02
05-12-2007, 09:05 PM
Im gonna have to say that yes it will be able to be shoved into the stock intake manifold, however if I were to have used a yfz carb with the cast flange for the air boot, the stock 400 intake boot would not reach the carb. most likely can just move the air box forward an inch or so and it will reach, I also know the I.D. of the stock air boot is right at 2-1/4". not sure how large the cast flange is on the YFZ's I can let you know though cuz my girls got a YFZ.