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FCR 39 Pilot Jet

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Since my fuel screw had no effect on my idle,I changed out the EMN and put in the EMR at 3rd clip.

After the needle change,the bike would at least stall with the fuel screw all the way in.

I searched all I could. I then changed the Pilot screw from a 45 to a 42.

The fuel screw still has to be all the way in to stall the engine .

The question I have is . Should I put the EMN back in. Or should I go down to a 40 Pilot jet.

EMR needle at 3rd clip

200 main air jet

160 main jet

42 pilot jet

100 pilot air jet

FMF header

White bros 2 exhaust.

Thanks,Gregg.

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You shouldn't be looking at changing the needle for idle settings. If the bike stalls when the fuel screw is all the way in that is not a bad thing. The important thing is to have control of the idle with the screw. Perform the Mixture Screw/Pilot Jet test thingy in the FAQ sub forum (I pretty sure its ther or search it) but only worry about the needle on throttle openings.

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I am no expert by any means but I have spent some time looking at the Sudco catalog (page 41) FCR needles and have experimented with several needles & pilot jets to find the best combo for my FCR. The three letters that make up the needle designation indicate the taper. length, and diameter of the needle. The diameter plays a roll in idle to 1/4 throttle. This part of the needle controls flow past the needle at idle when the slide is all the way down. The larger the diameter the less fuel is allowed by which adds to the fuel the pilot is metering. They share the load as it were. I try to set mine up so that the pilot jet is controling 75% of the fuel load at idle so I can adjust it better and get more response from the screw. If the needle diameter is to small to much fuel gets past the needle and you can't stall the engine or adjust the screw very well. I have a ELQ needle with a 48 pilot and I have a good solid idle and excellent throttle response at low speeds, it also give me a little more fuel when its on the taper which seems to work well too. (Still have a 160main jet) "L" taper is richer than "M''. When I tried a smaller pilot I had to much decel popping and had to turn the screw more than 3 turns to reduce it but could not get rid of it completley. I also could not use the choke with the EMN needle as it was getting to much fuel already and I could start it right up cold and it would idle already which told me it was to rich at idle but was getting decel popping so I was getting confused until I tried a larger needle diameter and "BAM" I could adjust the screw to stall it and could set it perfectly to eliminate popping with it as lean as possible, so with a larger pilot and smaller needle diameter I hit on a combo that gave me a perfect idle, with the screw set about 2 turns out, no popping, no bog, no hesitation, smooth throttle response from idle to redline and ripping fast accerlation no matter how fast I twist it and I 'm using a 1/5 turn throttle tube and now the choke works again too. Its all about finding the correct balance for your version FCR carb & situation. Thank God you can change the needles & jets without removing the carb or I would still be at it as I must have tried a dozen combos until I hit it. Hope this helps. 👍

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You shouldn't be looking at changing the needle for idle settings. If the bike stalls when the fuel screw is all the way in that is not a bad thing. The important thing is to have control of the idle with the screw.

thats the thing, the fuel screw does nothing. I am trying to get the fuel screw to have an effect . Nothing happens from all the way in till it falls out.

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I forgot to mention that you may have to remove the #100 pilot air jet to get the pilot circut to work for you, otherwise it may be to rich no matter what you do. It sucks unfortunately because you have to remove the carb from the bike and unbolt the intake adapter to get at it. If you loosen up the subframe and tip it back its easier to get the carb out. 👍

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Yes, the pilot air jet (aka slow air jet) should be removed for anf TT store FCR-MX kit

My mistake, I did remove that jet.

On another note. Thanks William, lowering the idle before adjusting the fuel screw did the trick. I am a very happy camper.👍

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FYI, when the bike is at its' normal idle, it is slightly on the needle as the normal idle for a DRZ is right at the transition point from the pilot circuit to where the needle is just coming into play.

A DRZ can idle lower than ideal but being a thumper, a "Band, rotate, rotate, Bang" puts a fair amount of stress on the rod and piston. So we run a slightly high idle "BangrotaterotateBang". 👍

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FYI, when the bike is at its' normal idle, it is slightly on the needle as the normal idle for a DRZ is right at the transition point from the pilot circuit to where the needle is just coming into play.

A DRZ can idle lower than ideal but being a thumper, a "Band, rotate, rotate, Bang" puts a fair amount of stress on the rod and piston. So we run a slightly high idle "BangrotaterotateBang". :worthy:

Gotcha, I raised it after fine tuning the fuel screw.👍

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I'll probably have to change my pilot jet up or down ,and when I was to order in tt shpo ,there's 2 series pj's for the fcr 21 series and 22 series.

Which is the correct one ?

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