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I have fuel leaking out of the float bowl drain tubes, I'm told that my float needle valve is stuck open, I've tryed putting my raptor on its ass and then letting it fall onto the front suspension. I've tryed blowing air into the fuel inlet and the drain tubes, I've also sprayed carb & choke cleaner into it, it reduced the flow of leaking fuel but did not stop it. I have thought of taking the float bowl off but the screws are hard to get to. Does it sound like float or needle valve adjustment problem instead of a needle stuck open by sand or varnish from bad gas? Any other suggestions?
 

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I agree it`s not to hard to get them off but beware of the brass/gold screws that strip out so easy. I could not avoid this on my my 03 raport or 03 kfx 400. the raptor carb I got 1 screw out of 8 to beak free with screwdriver and 2out of 4 on the kfx. The rest wher have to be removed by tiny to reguler size small vice grip pliers. It`s said to put in allen screws next time to save the headach of the philpe heads from striping. I learn alot by takeing my carb apart such as the shop never put my jet it in! and I learn to clean the carb and check everythang. Inspect and clean and reinstall.
 

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those 8 philips screws on the bowls of the carbs is another of Yamaha's big no no's. I had to use a impact screwdriver to loosen mine(i couldn't imagine using vice grips akwilliam....that must of been a pain in the butt). Buy new Allen bolts and use antisieze on them.....do not overtighten.

Max
 

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Put a small block of wood just at the side of the carb (to buffer it) and give it a few good smacks with a hammer, start it up for a few, rev it, repeat about two or three times. most times that'll do the trick, the other times you'll need to clean your carb, or readjust your float. The screws are a pain in the but to get out, another trick, put a phillips screwdriver in the screw and smack the back of it with a hammer lightly, that'll usually loosen that screw (always worked for me). Take Maxb750's advice about getting the other fasteners after you get those out, its not going to be your last time in those carbs.
 

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I thank the screws are poor design on mikuni part not just yamaha. Yamaha builds the carb useing mikuni carb/parts from what i understand. This 03 kfx400 has a mikuni carb same type screws same problem.

Yeah useing vicegrips are a pain it took a very long time and many clamps and slips before i could get them to breakfree and turn out. I had some like ez out taps that are ment for philpe screws but I would not use it cuase it would have eatin up the inside of the head and cause more trouble. I have used a square bit and allenhead and beat it in the striped screw and have had luck. Lucky the screw head bends.smashes kinda flat when alot of pressure is applyed with vice grips. One tip is to buy tiny small and reguler size vicegrips and make sure you are as far down on the screw as you can get and squezz as hard as you can to get them to lock and hold them so it will not try to slip off. If this fails and your vice grips round it off bad and you dont want to try to tap them out by drilling than best to get a tiny air die grinder which could be had for cheap and be carefull and grind the rounded part flat and try to get on them again with vice grips. I find the tiny/small vice works best to start with cause some screws can be tight fit for the vice and you wont be able to get a good angle on them. Dont use old wore out vice like me or you be sliping off of it all night lol. Dont let the striping out scare you from takeing them off!!!!!
 
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