FCR High Idle

I have a Slant FCR Carb w/EMN Needle all set up with TT settings. The bike also has

* Stock E Model Airbox

* Stock E Model Header

* Twin Air Filter

*Pro Circuit T-4 with 3/8 baffle

I have noticed that when the bike gets warm the idle will hang slightly, sort of like a 2 stroke leaning out. When I blip the throttle it sometimes will hang up about 500+ rpm and then settle back down. Not a big issue but I was wondering what the cause and adjustments would be. It also pops abit on the over-run. Other than that it runs real crisp and strong. I have checked to make sure there are no air leaks but as far as settings - no clue.

I am running the vacuum petcock.

Any advice?

Fuel screw adjustment/pilot jet. Make sure cables are correct and nothing is contacting the throttle area.

So I would turn out the fuel screw about a half and see?

With the eng. warmed up, adj. FS to achieve the highest possible idle, then turn the idle screw back down to normal speed. Have you confirmed pilot jet size and there are no air leaks? The carb is clean right.

Carb is clean (new), no air leaks or binding in the linkage/cable. Not sure of the jettinng as I just bought the bike and have only put about 450 miles on it so far but the PO applied all the TT settings..

Bike just recieved a bunch of mods and maintenance before I picked it up so it may be a bit of dialing in that's all.

I'll let you know. Thanks!

Make sure the slide isn't in upside down, I had a hanging idle on my FCRMX and that was the problem.

Make sure the slide isn't in upside down, I had a hanging idle on my FCRMX and that was the problem.

Same here:banghead:

Anyone have a schematic/exploded view of the FCR carb?

Sudco has the mx version exploded view.

Eddie you and the Faq has been a big help. I will turn some scews tonight!


I had the same symptoms, and in my case the throttle wheel was just touching the frame towards the end (Upon releasing the throttle). It takes you only 2 seconds to check it. I had to loosen the clamps, tweak the carb, and re-tighten.

I'll check that too!


I'll check that too!


And while you are in there....remove the right engine to frame mount, and put it in place next to the left mount. That way you can rotate the carb just a little so the throttle wheel will have clearance....:worthy::lol:


The throttle wheel clearance gave me fits also but the FCR is The REAL DEAL !!!

Throttle cables and wheel are all clear. I opened up the fuel screw and the problem has gone away.

Thanks eveyone!:worthy:

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