Keihin 39mm FCR-MX Install, DR650

[brianwheelies]

But man did you ever waste time on that old BST project.

Can't say that it was time wasted since everyone was able to get some great info on setup for the BSSSSSSTTTTTTTT!

[djchan]

JRS200 - us KTM guys have been switching to FCRs for years. Nothing new there. I've kept my BST on the LC4e because it gets over 50mpg, doesn't cut out in the whoops (almost always a float issue) and power wheelies 1st, second and third. Even at that I've thought of the FCR cause, well....we always want more don't we.

Dean

[NordieBoy]

Considering these are all off of YFZ450 Four Wheelers there must be some ragged running units out there. I can't beleive the vast array and sizes of jets. I'm gonna have a pile of worthless FCR jetting stuff.

Put them back up on ebay

[mxrob]

I'd like to apologize to the guys that are getting my FCR's. I fully expected my web site to be up and running so you could look at the instructions for installation. You do need to follow them to limit frustration levels when installing the big carb. It does fit nicely however. Comcast couldn't have picked a crappier time to "rebuild the world" in the home page servers.

Shortened instructions:

OK, grab the FCR and remove the throttle cam access cover with your 4mm allen wrench. Take your properly routed push cable and spin the two locking nuts all the way up to the end of the threads on the cable sweep curve. Install the inner cable through the slit in the 6mm1.0 threaded hole on the top of the throttle cam casting. Remember you are doing this without the carb mounted on the bike yet! Thread the carb onto the push cable by spinning the carb around the cable sweep. When the cable sweep comes to the end of the threaded hole install the push cable end on the cam. Do not install the pull cable yet! Here is your first adjustment. Push your throttle grip back against the hard stop in the throttle assembly. Check the play in the inner cable at the carb cam. Spin the carb back out until there is just a bit of play in this inner cable with the cable sweep pointing to the left. You've gone too far if the cam on the carb is what is trying to stop the throttle grip from making it to the hard stop in the throttle assembly. The limitation here is we need the cable sweep to be pointing to the left. If you return the throttle grip to the hard stop there should be a bit of up and down play in the cable at the carb cam. It it pulls tight go one more turn back in with the cable sweep. Spin the locking nuts down to lock the cable pointing to the left. You will readjust this angle a bit once the carb is mounted.

Now install the pull cable. Spin the lower adjuster nut to the end of the cable sweep making sure the nut has full thread contact with the cable sweep. Slide the barrel end into the cam and route the inner cable around the cam. Open the upper lock nut far enough to allow the sweep adjuster to slide into the lower pull cable carb casting groove. Make sure it's fully seated at the back of the groove. Spin the upper nut down and tighten it with the sweep pointing in the same direction as the push cable. Now loosen the pull cable adjuster near the throttle and spin it open to take up the excess play leaving a bit of slop. (You'll make final adjustments to this once the bike is all back together). Check to see if the throttle works properly. If all looks good install the cam cover back on the FCR.

Now to install the carb... but first you need to remember to remove the rags from your manifold and air boot! ;-) Install the FCR into the manifold first by backing the carb into the air boot area and swinging the front of the cab into the manifold area. Yeah, it's a bit tight... that's why I had you remove the clamps completely and unbolt the air box. Don't even think about the air boot just yet or worry about getting it onto the adapter. The carb fits tight in the manifold so you'll have to wrestle it around a bit to fully seat it. On the left side of the carb spigot there is a small square casting which needs to be bottomed up against the rubber manifold to ensure the carb is seated properly in the rubber manifold. Get the carb straight up and down! Spend a few minutes making sure the carb is fully seated in the manifold and vertical. Now grab the smaller screw less manifold clamp. With the open end facing up and the staked on nut closest to you slip the clamp up over the manifold into it's groove. Spin the clamp around the groove 180 degrees so that the screw is at the bottom. Reach back and grab the nut side of the clamp and squeeze it together with the bolt hole side between your index finger and thumb so you can get the screw started. Make sure the clamp does not slide forward as you tighten it. Force it back towards the carb in it's groove before tightening. Cinch it down well so the carb tries to twist the rubber when you attempt to rotate it in the manifold. Note: Both of the engine vent lines should be on the outside of the throttle cam cover not pinched between the frame and the carb where they could cause back pressure from restriction or pinch the carb venting lines in any way!

If you've already modified the air box and removed the screen continue with the air boot. It might be crumpled a bit and not on the adapter. Use your fingers or a small screwdriver in the rubber to get it onto the adapter. Do the same technique with the air boot clamp as with the manifold clamp. Use the nice groove in the air boot to guide the clamp around to the bottom of the boot. The venting lines may have to be pulled back away from the carb a bit to allow the clamp nut to clear around the groove. Get the screw started in the clamp and just slightly tightened down. Now grab that loose air box and make sure the air boot is fully seated and square on the adapter... tighten the clamp. Re-install the air box bolts putting a drop of thread locker on each one. Don't go crazy tightening these 6mm bolts... the internal nuts are brass.

Refocus on the cable routing and ties. Tidy things up under the tank and re-aim the cable sweeps as required to make the least amount of bends and contortions in the cables. Tighten the locking nuts. Put a dab of silicone sealant in the inner cable slit for the push cable on the carb casting to prevent water and dirt from entering the enclosed cam. Check that the routing of the vent lines are correct and are in their guide hoops on the carb. Install the supplied translucent carb bowl drain line on the drain fitting and route the line back behind the engine and between the rear linkage mount on the frame. It's a bit of a tight fit but it holds the line so it will stay in position when you need to drain the float bowl. Leave a little extra length between the carb and where it fits snugly between the engine and the frame so you have enough play to allow the carb to swing for jetting changes without having to remove the hose from the fitting. It's very tight as you'll find out. Soaking the end of the urethane hose in some hot water will make for an easier install onto the carb fitting. Cut any excess length off at the bottom so it just clears your skid plate. Make sure to cut the hose at a 45 degree angle with the open side facing backwards to minimize mung and glop from plugging the line.

Install the vacuum petcock line onto the fitting on the FCR. Route the hose down through through the YFZ's electrical cable guide on the TPS block and let it hang there. Double check that the throttle is operating properly and that nothing is catching or binding when you turn the handle bars from steering stop to steering stop. Install the gas tank making sure the throttle cables are routed below front rubber tank mounts. At this point if you've decided to use the choke cable you'll need to install the enrichening device into the carb body. Because of where the port is on the FCR you have to install this after installing the tank... and remove it before removing the tank. An open end 12mm wrench and a bit of patience will allow you to complete the task. Remember this plastic cable mount will break if you look at it funny. Be cautious. Install the vacuum line on the petcock and the fuel line with clamp on the carb. Stick a drain pan under your bike below the newly installed float bowl drain line. Open the 3mm allen head cap screw drain valve a turn or two. Turn the fuel tank to prime and allow the fuel to run through a bit making sure we've rinsed out any dust or dirt from the shipping and installation process. While it's draining a bit close the drain valve and allow the carb to fill completely while you finish bolting down the tank, install the seat and side covers. Use the locktite... it's still a thumper! Turn the petcock to on.

Now is the time to finish the pull cable adjustment. Turn your bars fully to the left and adjust the take up near the throttle until it hits the point that it is trying to open the throttle. Back it off a little then turn the bars to the right. Find whichever position is the tightest and adjust your cable play so that the throttle isn't opened when you turn the bars to full lock. The only change that may occur is when you finally set your hot engine idle speed. Recheck your cable play afterwards.

If you haven't ground your head pipe weld now is the time! This carb is jetted for sea level with the air box mod, TwinAir foam filter, screen removed and the header weld ground using the FMF-Q2. If you are using a more restrictive exhaust like the Staintune with the baffle in you will need to adjust your jetting accordingly! You will also need to make jetting changes for high altitude or any other variables that may effect jetting. If you are planning on using the stock muffler I will install the 162 main and set the clip to the 4th position for you. The bottom line is you are responsible to assure your engine isn't in melt down mode or overly rich for whatever reasons which vary from the above stated conditions! I only have experience and data from at or near sea level conditions with the installed equipment listed above.

Speaking of hot engines... start that baby up! I will have set the pilot to two turns out and made my best guess on the idle stop based on how my carb is set but that will need the final adjustments for your bike. Follow that up with the final pull cable adjustment mentioned above.

Enjoy!

mx_rob

[Benrod327]

Well I manage to finally shoe horn the FCR in it wasn't easy but I can be a bone head sometimes plus at the time I was putting it in this morning I couldn't appreciate MX-Robs detailed instrucions above (It's okay Rob) obviously the throttle cables had to be switched to the other side which was no big deal. The main problem was getting it in. I unbolted the rear brake reservoir and comensed to "shoe horn" it in there. Like I said I'm a bone head and didn't remove the boot clamps so they got all bent up and then wised up and took both of them off, then managed to stretch the outer cable protector for my throttle return cable (I should still be fine right Rob) and then managed to get it in. Then by that time I ran out of time and had to go to work but I think I have to take it back out and canoodle with my throttle cables again I fear that the return is not cooperating as it should, even though Rob said the return spring is lighter then the BST I think I need to get it smoother. Maybe I should re-assemble it all first and see how it feels.

[jrs200]

Can't say that it was time wasted since everyone was able to get some great info on setup for the BSSSSSSTTTTTTTT!

I was just being sarcastic Brian. I don't plan on getting rid of my BST. My DR does great for what I do with it. And I am still using my Factory pro setup.

[Benrod327]

Well I got the bike all back together again it took a little longer cause I wanted to adjust my valves, and clean my air filter. So it's in there and rode it for a while and... IT IS AWSOME!!!! It's like night and day compared to the BST the 650 really come alive with this carb! I have the D606 on and have the 14 t cs, and a gravel drive way and was rooster tailing in third gear with not even half of the throttle! This thing pulls harder then ever! I noticed that the engine has a slightly different sound to it with the FCR on it, but to me it is in a good way! I'll be riding it more tomorrow more to test some more things out, but it will thump along in 5th gear up a hill at 35 mph no problem! I love it and am done with engine performance mods as we know it ( except for putting in a Twin Air filter). I am extremely pleased and Rob did a terrific job setting it up. I'll have to adjust the idle a bit lower but no big deal. Oh ya and Rob I broke the choke thingy that you broke on yours too. So in my expierence for the people that will be doing this leave off the choke cable until you put the tank back on to avoid breaking the end. I might just completely eliminate the cable altogether. Anyways I thought it was totally worth it. Now I'll work on the suspension this winter and come spring I'll feel unstopable on the trails!

[mxrob]

Well I got the bike all back together again it took a little longer cause I wanted to adjust my valves, and clean my air filter. So it's in there and rode it for a while and... IT IS AWSOME!!!! It's like night and day compared to the BST the 650 really come alive with this carb! I have the D606 on and have the 14 t cs, and a gravel drive way and was rooster tailing in third gear with not even half of the throttle! This thing pulls harder then ever! I noticed that the engine has a slightly different sound to it with the FCR on it, but to me it is in a good way! I'll be riding it more tomorrow more to test some more things out, but it will thump along in 5th gear up a hill at 35 mph no problem! I love it and am done with engine performance mods as we know it ( except for putting in a Twin Air filter). I am extremely pleased and Rob did a terrific job setting it up. I'll have to adjust the idle a bit lower but no big deal. Oh ya and Rob I broke the choke thingy that you broke on yours too. So in my expierence for the people that will be doing this leave off the choke cable until you put the tank back on to avoid breaking the end. I might just completely eliminate the cable altogether. Anyways I thought it was totally worth it. Now I'll work on the suspension this winter and come spring I'll feel unstopable on the trails!

Glad you got her running! Sorry about my web site. I had the choke cable thing all laid out in the instructions... yes, it has to be the last thing on after installing the tank and the first thing off before removing the tank because of the FCR's choke location. No big deal but it needs to be followed if you decide to not use the carb choke provided.

This whole web site deal has taught me a lesson and I will include full instructions with each carb from now on. My apologies to the guys that I've already sent the carbs to sans instructions.

The deeper sound is cool and the two part floating slide seal whistle at 1/8 throttle or so takes a bit of getting used to but you don't notice it once the ear to ear grin sets in. Thanks for the first owner ride report... I'm expecting many good ones!

[mxrob]

Well Mohawk's carb showed up today and I've run into my next lesson. Someone had changed the slow air jet from the 100 we need to a 70. So I thought no problem I'll just order a few from Sudco.... WRONG! The OEM carbs use a different slow air jet than the aftermarket Keihin FCR-MX's that Sudco sells. Now I have to go back through Yamaha or one of the other big four to buy these jets when they have been changed from stock. Guess I better order a few of them...

[mxrob]

Just a word of caution for those buying their own carbs. I see one on eBay right now that says YFZ450 along with CRF450. These are not the same carbs! This is not a39mm carb and it has the push cable casting machined out so our DR cable would not work with it. It also does not have the air-cut valve. These eBay guys slap everything they think the carb might fit in the listing....

[gravelrash07]

Hi Mx Rob, I'm being watching this post with great interest. The one big draw back I have found with my DR is the not so great low end power. Have the DJ kit,supertrapp,airbox mod. etc, all made an improvement mostly in mid range and above. Put in a 45 pilot from 42.5 helped abit. Just doesn't have the low end grunt like my last thumper-85 yamaha xt 600 but that bike had twin carbs-small dia unit for low speed and and a larger carb would come online when the throttle was increased. Also twin exhaust headers, she had knob ripping low end snort.

My question is: would going to the keihin fcr help the DR in low speed performance? Would be nice not to feather the clutch so much while climbing logs and rock strewn hills.

Yesterday I ended up in quite a blizzard when I went up in the hills for an afternoon ride brrrr it was cold. Nice and sunny 60 degrees in the valley bottom. Lucky I just changed the dulop 606s to metezler karoos for the ride. Would be nice to have two sets of rims, been watching ebay for quite awhile.

thks for any info

[mxrob]

Hi Mx Rob, I'm being watching this post with great interest. The one big draw back I have found with my DR is the not so great low end power. Have the DJ kit,supertrapp,airbox mod. etc, all made an improvement mostly in mid range and above. Put in a 45 pilot from 42.5 helped abit. Just doesn't have the low end grunt like my last thumper-85 yamaha xt 600 but that bike had twin carbs-small dia unit for low speed and and a larger carb would come online when the throttle was increased. Also twin exhaust headers, she had knob ripping low end snort.

My question is: would going to the keihin fcr help the DR in low speed performance? Would be nice not to feather the clutch so much while climbing logs and rock strewn hills.

Yesterday I ended up in quite a blizzard when I went up in the hills for an afternoon ride brrrr it was cold. Nice and sunny 60 degrees in the valley bottom. Lucky I just changed the dulop 606s to metezler karoos for the ride. Would be nice to have two sets of rims, been watching ebay for quite awhile.

thks for any info

The FCR makes an amazing difference in low end performance! It only stands to reason since the DR650 is a low end grunt engine.... which is being choked by the CV carb. The FCR also improves top end but the real meat and potatoes is low to mid range torque. Throttle response and tractability are both improved. Beleive me... with the air box mod and TwinAir foam filter, air boot screen removed, header pipe weld ground and the FMF-Q2 this is a whole different bike. I'm sure the supertrapp or other more straight through exhaust system would be very similar in output.

[berni]

Ditto that. Had the staged 2 barrel on the XL350R. What a sweet ride. If I could extrapolate that to the DR650 I'd be tickled pink. I bet she'd pull a 16 toof injun sprocket easy. I've been this close to PMing you to be put on the FCR list. The only flea in the ointment is the accel. pump. I do a lot of long distance touring and the thought of pumping fuel every time I even flinch my wrist....Am I all wet? Did the 750 Holley double pumpered BB Chevy skew my thinking? Is there a big hit with the mileage? Berni

[mxrob]

Ditto that. Had the staged 2 barrel on the XL350R. What a sweet ride. If I could extrapolate that to the DR650 I'd be tickled pink. I bet she'd pull a 16 toof injun sprocket easy. I've been this close to PMing you to be put on the FCR list. The only flea in the ointment is the accel. pump. I do a lot of long distance touring and the thought of pumping fuel every time I even flinch my wrist....Am I all wet? Did the 750 Holley double pumpered BB Chevy skew my thinking? Is there a big hit with the mileage? Berni

In my mileage testing I got the same mileage as my modded BST. My beleif is if a fella wanted to really exploit the mileage with this carb it could be done fairly easy. The accel pump is throttle velocity dependant as well... there is a small check ball that requires a certain pressure to remain closed...slight throttle movements do not seat the ball and the fuel bypasses the accel pump nozzle. There also is an adjustment on the pump that allows you to set the point at which it begins to provide extra fuel. The adjustability of this carb is great for the person who likes to tinker with jetting.

[berni]

Thanks for the quick comeback. If the range of AP adjustment is such that it can be taken off line until I grab real big handfulls I could make use of this carb. I'm way past the point now where I know what I am talking about. I should have, in front of me, a detailed FCR manual that explains all the features and available jetting c/w guidelines. I did send away for the Sudco/Mikuni manual (no keihin manual that I'm aware of) with the view to installing a slightly smaller , easily jetable carb. to drop the higher range hp in favor of a fatter low to midrange. Thanks again, Berni

[the_aussiedr650]

After the problems the_Aussiedr650 is having with the carb I shipped him I'm beginning to wonder... The main jet access plug is bent and leaking fuel and he's having issues with float level right now. Never would have dreamed someone could bend the main jet accesss plug... You can bet a straight edge goes on them from here on out. I check the 9mm float level and inspect the needle/seat. I hope just a chunk of crapola got in there or I'm gonna have to reveiw the light air flow level test procedure I'm using. I may have to set up a bench fuel tank. I just hate to put fuel in carb after cleaning it.

Rob,

All problems just about sorted just picking up a new Jet access plug on Tuesday but i pulled the float bowl off a couple of times and removed the float and needle but couldn't see any reason for the needle to not cut off but i made a couple of adjustments to the float level till it was perfect and refitted it all to the bike and it started first press. I have only had time for a short ride but the power now comes on strong from 1% throttle opening!!!!!!!!! more like a powerful electric motor torque curve. i have not moved the idle speed or the pilot screw at the moment as i have no reason too! it just runs and idles better and seems to do everything better.Further ride report to follow:devil: .

Thanks Rick:ride:

[mxrob]

Rob,

All problems just about sorted just picking up a new Jet access plug on Tuesday but i pulled the float bowl off a couple of times and removed the float and needle but couldn't see any reason for the needle to not cut off but i made a couple of adjustments to the float level till it was perfect and refitted it all to the bike and it started first press. I have only had time for a short ride but the power now comes on strong from 1% throttle opening!!!!!!!!! more like a powerful electric motor torque curve. i have not moved the idle speed or the pilot screw at the moment as i have no reason too! it just runs and idles better and seems to do everything better.Further ride report to follow:devil: .

Thanks Rick:ride:

Phew! Man, I'm feeling better now... So sorry about this drama I sent you through. I just have to expect the unexpected on these carbs... and based on how some of them have been put back together when the PO was trying to make jetting changes I should have known better. I know some of these guys are selling their carbs because after installing their new jetting they couldn't get the thing running right so they off'd it and just bought a new bigger carb. The upside down floating slide seal is the biggest mistake. I bet the first part of the throttle ran just like poop on these four wheelers. The backwards accel pump diaphragm with the spring on the wrong side was another performance enhancer.

Looking forward to a full ride report!

[mxrob]

Thanks for the quick comeback. If the range of AP adjustment is such that it can be taken off line until I grab real big handfulls I could make use of this carb. I'm way past the point now where I know what I am talking about. I should have, in front of me, a detailed FCR manual that explains all the features and available jetting c/w guidelines. I did send away for the Sudco/Mikuni manual (no keihin manual that I'm aware of) with the view to installing a slightly smaller , easily jetable carb. to drop the higher range hp in favor of a fatter low to midrange. Thanks again, Berni

There is an adjustment screw on the accel pump cam inside the throttle cam cover that allows you to change the timing of the accelerator pump's operation. The larger the gap you leave the more handfull of throttle you need to get the pump to enrichen the mixture. There are also other pins available that allow you to taylor the accel pump to your needs. Unless you have a real nervous throttle hand I'm pretty sure you are too skewed by Holley Double Pumper dreams.

[mxrob]

Ditto that. Had the staged 2 barrel on the XL350R. What a sweet ride. If I could extrapolate that to the DR650 I'd be tickled pink. I bet she'd pull a 16 toof injun sprocket easy. I've been this close to PMing you to be put on the FCR list. The only flea in the ointment is the accel. pump. I do a lot of long distance touring and the thought of pumping fuel every time I even flinch my wrist....Am I all wet? Did the 750 Holley double pumpered BB Chevy skew my thinking? Is there a big hit with the mileage? Berni

I have a restored dual carbed XR350R Plus 1-1/2 more in a huge pile of parts in my garage for later restoration.... the way things have been going... much later.

[berni]

XR350R, very nice. So you know what I'm talkin about. Is that a sweet motor or what? Re: dbl pumper dreams, bro and I swapped a 307/Pglide for 396/TH400 Chevelle when we were teens, many moons ago. Not the kind of build you would see on T.V. unless it was on "Cops" or "Americas Most Wanted". Got a couple funny stories involving hijinks and angry grownups but this isn't the forum for that.