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XR650L FCR jetting

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I have a 99 XR650L. I had it bored out and a 102mm 10.5/1 piston put in. I also had a hot cam slotted and degreed in. I had a full white brothers e-series set up put on header wraped and all. Ported, and some valve work done to increase performance. I bought a Keihin FCR 41mm carb and am having a hard time gettting it dialed in. Does anyone out there have a XR650L that is highly modified that is currently running this carb, if so can you give me an idea of where to start from(jetting, clip position, ect.).

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The needle is what ever comes in them stock with the clip in the middle and I am not sure what the jetting is at this point. I have changed it so many times after each mod trying to get it right. I think right now it is some where around 168 main 52 pilot. But I am not sure.

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I am jumping in on this one

I have most of the same mods on my "XR675L" as you.

I have been fighting my FCR for a couple of months now.

Here is what I have carb wise

Needle OCEMR (or is it OCMER?)

Main 170

pilot/slow 48 to 65

& JD needles with a 180 main

And I have tried every combo of needle clip position and slow jet size along with adjusting the air screw.

My prob has been that I cannot for the life of me get the thing to idle well. It always seems to stumble & die. I have heard this called "flameout". I have been trying everything & talking to everyone for thoughts. Some have said it's lean some rich try this or that. nothing has cured it.

All I know is that with the blue JD needle clip in the 2-4 position 180 main and the 65 slow jet the thing pulls in the mid range & upper range awesome!

I loved it, it ripped (if an XR650L can rip)...

But it dies on idle, if I put a 48-55 slow jet it won't even idle at all, and to start with the 48-55 you have to whip the throttle so that the accel pump is throwing gas into the intake. This was the same prob I had when I first put the carb on with zero engine mods. I just changed the pilot to a 55 I think it was and it was great, now I am stumped.

Okay now Burned is going to say what about your float height, well I tried adjusting it but it was not easy for me. So I talked to a mech. friend and we are going to make sure that it is correct, "he's got an awesome set of tools"

For some reason I don't think it's the float since it wasn't even touched and worked great before.

I am all ears to suggestions.

Travis

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Okay I guess I need to reintroduce myself... Hi my name is Travis, I am the local village idiot.

I am looking at my manual and where is the pilot slow jet (supposed to be a 100 or 200 right?). Is it in the float bowl?

I also did the float level it was way off like by 4 or 5mm.

Travis

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the pilot air jet and main air jet are under the intake bell.the main ir jet is the center and the pilot air jet in on left.

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Okay just to make sure I am oriented correctly the jet on the right (looking into the intake side) is the main air, it is a 200 the jet on the left is an adjustable type, spring-screw ( how many turns out?)

BTW Thanks so much for your help!!!

Travis

Just noticed something on the Sudco FCR diagram on their web page, I don't recall my needle having a spring on the top of it ( it is the older style FCR) do I need that or is it part of the new carb?

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your cabr doesnt have the spring on top of the needle.your fine.

with a 48 pilot jet set the pilot air screw (the one on the left) at 1 turn out from lightly seated.

set your fuel screw at 2 turns out and see what you get.

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Okay so here is what we have

48 pilot

180 main

JD blue needle #4 postition

1 turn out on the pilot air jet

200 main air jet

2 turns out on fuel air screw

Float level set to factory 9mm setting

Air box is opened way up

675cc motor with a 10:5 to 1 comp. piston

Stage 2 Hotcam

FMF Q pipe with Power Bomb header

The bike runs great but does still have a little cough at idle. It does the "flameout" once and a while. It is a bit hard to start when cold. It takes a bit of throttle work to keep it running when cold. Once warmed up it seems to do better.

So while not perfect it is much better.

Travis

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Village Idiot reporting...

Uh fuel screw? "Mom where is the fuel screw" "uh, go ask Mr. burned"

Travis

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Oh yeah that one..

2 turns out I have always called that the air fuel screw, wrong?

Travis

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