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FCR issue resolved . . . . . almost

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To anyone who has a UK SM.

Fitted my new FCR last week and had fueling issues low down. I took someones advice and put a 40 pilot jet in. A great improvement :thumbsup: , though still a bit rich very low down the revs with fuel screw at 2 turns.

Gonna try fuel screw at 1 and a 1/2 turns. If it don't get any better by 1 turn out, I'm gonna try the 38 pilot I got.

I'll let you all know how it goes.

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Hay I just got that same carb, from a guy in isrial, have not put it on just yet, just wondering what the little adjustment is on the bottom toward the front?? it lookes like it's been broken off to clear the e-start, is it air or fuel screw or what. This is the fcr 39 it's got a red button biult in for the hot start above the choke.

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Are you sure it's broken off and not just the standard recessed fuel screw?

If it's the standard screw, you will be able to see the slotted head about 10mm into the hole.

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What main jet and exhaust pipes are you guys using?

I have a new FCR-MX here as well and going to buy jets tomorrow for the install.

I spent this evening shortening the choke knob to clear my Clarke tank. Looks good, worked great.

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I got Yosh RS3 SS 160 main jet.

I tried the 40 pilot today and kept winding the fuel screw in. I got to just off the stop and there's still a very small flat spot at low revs, only really noticable in traffic.

I'm gonna def put in my 38 pilot.

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I ended up with the 38 in mine. Runs awesome with my modified potato in my RS3.

I also lowered the needle.

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I got Yosh RS3 SS 160 main jet.

I tried the 40 pilot today and kept winding the fuel screw in. I got to just off the stop and there's still a very small flat spot at low revs, only really noticable in traffic.

I'm gonna def put in my 38 pilot.

I have a 155 main w/ stock exhaust and filter. I have gone from a 45 to a 42 and now a 40 and I can still bottom out the mixture screw and the bike runs fine. I guess I'll have to do the same.

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Thanks guys, this really helps. I just picked up a 38 pilot and 155 main, will start with that combo (stock S exhaust, 3X3)

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Thanks guys, this really helps. I just picked up a 38 pilot and 155 main, will start with that combo (stock S exhaust, 3X3)

Do you have a stock air filter too? If so, please let me know how that combo works out and where you have your fuel screw. I'm debating whether to go straight to the 35.

I'm going to get a K&N to see if that helps too.

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Do you have a stock air filter too? If so, please let me know how that combo works out and where you have your fuel screw. I'm debating whether to go straight to the 35.

I'm going to get a K&N to see if that helps too.

Yes, stock filter, I'll report back, may be a couple days.

What needle are you running? The EMN or EMR? The EMR would possibly also help, at least it is easy to swap and see if it's on hand. The last letter (N or R) designates the diameter, which influences 0-1/4 throttle (or 1/8-1/4 throttle depending on how you interpret the chart)

In theory may not affect idle, but there may be some overlap. R is leaner than N, the needle chart is on the Sudco website - look for needle N427-OC-xxx

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EMN. The one that wasn't in the carb stock. I'll keep it that way for now. Just trying to keep my variables down.

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