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Okay, 96 XCR with the monoblock, fresh rebuild (complete) running AAEN pipes. used a winderosa gasket kit, and had head gasket problems and o ring problems, installed OEM head gasket and O-Rings, now this:

Carbs are 38MM all synced, running 310 mains, 40 pilots (we originally had 35s in it), 1.5turns on air screw, and the needle is on position 2 from top.

Problem is we start it up, it idles around 1700 RPM, it will idle there as long as you want it to, TAP the throttle or goose it, instantly she revs up to 2800RPMS and stays there unless you hit the choke. this tells me she's running lean.

Took apart the fuel pump, found a bunch of crap in it. put it back together and same thing. sprayed some starter fluid around all seals and boots to no avail, sprayed something around the base gasket and the rpms went down a little bit, but it wasnt starter fluid, something else. running rich pre-mix for break in, and no change if airbox is added.

4 of us working on this, all of us stumped! please give us some ideas, suggestions, anything!
 

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Check for free play in throttle cables, you may need more slack. Make sure you check that they all pull open at same time and the slide bottom clears top of bore at WOT.

If you think it's fuel related, lower rpm to 14-1500 then open air screw to 2 or 2 1/4 turns and see what rpm is. If it went up pilot circuit was too rich and slides too high.

Not sure why you increased pilots and I am not saying that was wrong. A cold engine does not atomize fuel well. Richer pilots sometimes let you start and run engine without playing with choke but warmed up low speed running suffers. If you have to play with choke till motor idles on it's own may be inconvienient, but it tends to give better performance once warm.
 

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Warm it up and retighten all 8 of the nuts that hold the cylinders on. I rebuilt one last week and after it was hot, I noticed some exhaust leakage around the base gasket. I was able retighten almost every nut about another 1/4 turn when it was warm.
I usually have the best results on these motors when the throttle adjustment gives you about 1/4 inch opening on the carbs, about the diameter of a pencil or so.
Not an expert here but just trying to help.
 

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sounds to me like something in the throttle cables is binding or getting hooked up. Examine it carefully for cracks, wear etc. If the sled has over 5000 miles it may be worth the $40 just to get a new one regardless.
 

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it is too lean.
turn the mixture screws in some.
you may need to use 45 pilots if you can't richen the mixture up enough by turning in the mixture screws.
 
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