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
Factory pro sells direct. I purchased six a year ago. Also the dual squirt a/p from vertex. Very close to FI with both. Add a R&D float bowl with an externally adjustable leak jet and you have invested a lot of money.DocBob
Would there be any reason why we couldn't drill out our own emulsion tubes. Or is there more to it than 4 small holes? Has anyone got any idea on drill size looks similar to a #100 metering jet to me - so 1mm
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.
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.
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