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FCR emulsion tubes

31514 Views 53 Replies 26 Participants Last post by  Boblai
One of the critisims of the FCR carb is the emulsion tube (what the needele slides up and down in and the main jet bolts on the bottom of) also referred to as the "needle jet"

Ideally 4 strokes need a drilled emulsion which atomises the fuel as it's pulled up the tube, hence the name "emulsion"


If you look in the guts of Weber or dellorto carbs used in off road racing automotive engines years ago they used drilled emulsion tubes and you could get a wide selection of drill pattern as to fine tune the fuel delivery.

anyways Travis at Thumper can supply these very nicely made drilled emulsion tubes or needle jets. Significantly improved throttle response due to the better fuel atomisation compared to the stocker. installation details to follow

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What Sunday? hopefully not too much power an ripped your arms off? lol
those ones from factory pro look like they have holes around where the needle slides do all these tubes have that or just the side holes in the tube?
Update. I raced the quad Sunday and have to say the emulsion tube fron KTMBIll was very noticable. I have never had such crisp throttle respnse from a carbed bike. It is worth every penny just on that alone. I will be putting the bike on the dyno in the near future. to see the gains as well.
Very nice! Did you make any other motor or jetting related changes when you put the emulsion tube in?
another happy user ! :cool:
Just put it in, No jetting changes. Best money spent. I highly recommend this update to anyone who truly wants performance gains. I can not emphasize enough the difference in the throttle response. Very crisp. And just a note this is on a 525 with 12:1 CP piston and a ported and polished head with a Baldwin XC cam. But I am rating this on the carb function only.
We are doing a package deal for the drilled emulsion tube and a dual spray a/p nozzle. $80 shipped. I'll have it on the web site next week.

I'll take one, I'll pm you

what exactly does the dual spray nozzle do exactly? I assume squirt more fuel? Do you have to do any jetting changes if you install both emulsion tube and dual spray acc pump nozzle? As you can tell I only have a basic understanding of a carb? Answers would be appreciated.
no jetting changes should be needed for the emulsion tube. dual squirter shouldn't either, but may require a leak jet change? I dont think mine did, but honestly i dont remember. i run the dual squirter on my race quad, nice improvement, much better throttle response. the two smaller squirts of fuel allows the fuel to atomize easier, when comparing to one larger single squirt.
Is the dual squirt AP nozzle something you can install at home or does it need to be shipped off? It looks like a press fit with not much room to work in. I'd think it would be difficult but hopefully not.
full carburetor disassembly is required. takes a taper proof t-15? i think its 15... might need to lightly tap the top of the nozzle that is in there to get it out. other one just gets installed in same hole and you will have to line it up somewhat... not too difficult.
It's a 20 tamper proof Torx bit we supply a torx wrench with the dual spray as of last week. I'm still working on packaging and instructions. you will want to add a piece of safety wire around the A/P linkage set the gap tp .120"

On a gen 2 carb (the carb with the removable inlet bell) no quads came with a gen 2 carb BTW. You will want to put a little paint stripper on the tamper paint and leave it on there of 10 minutes then scrape it out and you can then insert a 3mm allen wrench. Make sure to use the proper protective equipment and rinse thoroughly before handling the carb with your bare hands, paint stripper is caustic.

The old nozzle is lightly pressed into the carb body. There is a slot on the bottom of the nozzle using a small screw driver give it a twist before trying to press it out this will loosen the nozzle and make it easier to press out. The dual spray nozzle has a dot on one side of the slot. This needs to be installed with the dot towards the engine the screw driver slot needs to be 90 degrees to the airflow through the carb. I will get instructions on the web this week.
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full carburetor disassembly is required. takes a taper proof t-15? i think its 15... might need to lightly tap the top of the nozzle that is in there to get it out. other one just gets installed in same hole and you will have to line it up somewhat... not too difficult.
5lblmbn2009 is correct the fuel from the A/P is not reduced in volume having the stream split allows the fuel to be atomized better which means you get a better and more efficient burn during acceleration and that gives better response and a cleaner burn. It makes for a much crisper response while accelerating.

The wrench is a tamper proof T-20. We found a supplier for the wrenches and are now supplying them with the kits. Using a small screw driver twist the screw clock-wise and counter clock-wise to loosen the nozzle before trying to push it out. Turning the nozzle makes it easier to press out. Once you have loosened the nozzle then place the carb body on a hard flat surface and press the nozzle out using the side of a large screw driver. Your new Dual spray A/P nozzle has a slot on the bottom and a dot on one side of the slot. The dot should be pointed at the engine. The slot should be 90 degrees from the airflow. Using a little safety wire set the A/P linkage to .120 and then wire it together.
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I cannot find this package from thumper site.
Is it available?
Could someone post a link.
Just email thumper and they will sort you out
thumper just did my carb. 41mm, emulsion tube & dual squirt. should be here tomorrow. so I know he's still doing this.
Yup parts aren't on site, just call or email and he'll sort you out
I AM INSTALLING MY KIT NOW! What does thumper mean about using an ap wire setting to .120? No wire came in the kit they sent me, just the squirter nozzle and emulsion tube oh and the safety wrench
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