2007 Husqvarna 610 SM. Leo Vince slip on stock header opened up airbox JD jet kit. 182 main blue needle, 3rd clip position 2 turns out on the fuel screw sea level, low humidity o-ring mod iridium spark plug. TPS plugged in. So the bike starts up fine. Cannot idle at all. has a stutter at 4000+ rpms when at constant throttle. Not sure what i should do to fix this? any suggestions would be appreciated!
The what fuel circuit is being used depends on the position of the throttle as opposed to the rpms. Put some masking tape, blue painters tape, even duct tape, anything to indicate the position of the throttle then ride it and report back where the stumble is - my hunch is 3/8 throttle. Then figure out what size pilot jet. If you need to open the carb you may as well look at what size the leak jet is. Until those things are known it is a bit hard to guess but.... you may have too big a pilot (50?) and the blue needle is giving it even more fuel. If that is what is going on then maybe a 45 pilot, adjust the fuel screw for max rpms (1.5 turns out?) and switching to the red needle with clip at 4th position might do the trick. EDIT - when youi are testing the throttle positions it needs to be ridden, not in neutral in the garage. Usually 3 or 4th gear on a slight incline works best.
From the sounds of things right now you are ridiculously rich. This jetting should be just about perfect for you but the fact that it is not idleing at all could be a sign of something else besides jetting. Main jet ................................178 Pilot jet...................................45 Starting jet..............................85 Main Air.................................200 Low Air..................................100 Needle...................................OBDVR or JD..Red Needle position........................4th from top Leak jet ................................#60 Mixture screw......................... 1.5-2.0 turns out
ok so tonight i changed out the needle. So what i got now is: 180 main jet 50 pilot jet JD red needle 3rd from the top fuel screw at 2 turns so now im running much better. But still have a slight hesitation at 1/4 to 1/2 throttle. maybe im still running a little rich? maybe 4th clip position from the top on the red needle?
Way too big of a pilot jet... Put in a 45 pilot jet & change down to clip #4 red needle. While you are in there find out what leak jet you have (bottom of float bowel). If you do not have a 45 just say what smaller pilot you do have.
Hesitation from 1/4 to 3/4 throttle is a needle issue. You are to rich on the needle. Like Coffee stated, you are to rich on the Pilot also which is giving you to much fuel at the beginning and probably bleeding into the needle area. If you dont have the next leaner pilot then screw in your fuel screw about 1/2 to 1 turn. for the needle, you need to raise the clip to the next highest position. If you are 3rd from the top, going leaner would be 2nd from the top. That is going pretty lean for the blue needle. If that doesnt do it or it is still there but cleans it up some, my next move would be to the red needle (Next Leanest) on the middle clip position. Middle clip position on a red needle is the same as a blue needle in the first and second clip position. Mike
thanks guys for the help. Hi mike do you mean 4th from the top instead of 2nd from the top to make it leaner? and im currently running the red needle 3rd clip position from the top. Coffee. At the moment i only have one pilot jet.. which I believe is the 50. I will try the 4th clip position on the red needle and go to the dealer to pick up a smaller pilot jet or maybe do what mike said and turn the fuel screw in a bit i am also running the stock leak jet if that means anything to you guys? im not sure what it is myself... Here is what i am running at the moment Main Jet 180 JD red needle 3rd position from the top 2 turns on fuel screw (and the rest stock which is shown below from the husky manual if you can make sense of it) Low Speed Jet, 50 Starting Jet, 85 Main Air Jet, 200 Low Air Jet, 100 Starting Air Jet, 0.16 in
Then just screw in the fuel screw - possibly all the way in. The pilot jet is in parallel with the fuel screw and the combination of both determine how much fuel is delivered when idling. The pilot should be adjusted for max rpms at idle. Keep turning in the fuel screw and it should run much better at idle. You will still have a bit too much fuel at 3/8 (ish) throttle position so you may as well leave the needle alone for the time being. After you experiment a bit then take the leak jet out and read it, there really is no standard leak jet size. After you do all that PM me your address and I'll mail you some jets... I think I've got what you need. And of course you really really should have an after market fuel screw that you can turn with your fingers, makes life much easier.
thanks coffee! yeah i definitely need to go purchase a fuel screw... its basically impossible to turn the fuel screw with the bike running.... i've taken off the gas tank to get to the carb so many times now... and mike i think im getting myself confused what you were saying now makes sense to me. aha ok i will test this once i get the fuel screw..
ddub9 raising the clip to the next higher position Leans the needle. the top position is leaner. as you drop the clip to the pointy end, you richen the needle. mike
went to the dealer yesterday and picked up a merge fuel screw..... 30 bones for this little thing. havent installed it yet. probably will next week. anyways as the day seemed to get warmer the stutter at 1/2 to 1/4 seemed to go away. if that helps in any diagnoses.
Sounds right. You need a pilot jet about size 45, and a leak jet in the 55-70 range. I'm not sure what your schedule is but if you can figure out what you have for sure in the bike you can order one now or I can send some in the mail. (First you said you had a 50 pilot jet, then it sounded like you are not sure) The JD kit usually has pilot & leak jets so you may want to double check in the kit first. Let me know.
yeah im not 100% sure what pilot I have. I said 50 because that is what the manual says but I haven't physically checked it yet. I will probably have time next week to get a better look at it and to install the fuel screw along with the pilot jet. coffee I'll check with my dealer first to see if they have some pilot and leak jets in stock which they probably should. Unfortunately my JD kit only came with four main jets, 2 orings, and 2 needles.
alright so just switched out my my 50 pilot for a 45 pilot jet and installed a merge fuel screw (turned out 1 3/4 at the moment). at 1/4 to 1/2 still have a minor stutter but better than before. couldnt change my leak jet since my dealers didnt carry any in stock.... so im running the stock leak jet at the moment.
What size is it? What is your elevation & temperature in Canada when you are testing? Can I assume your testing while riding?
The stock leak jet is a blank. You can use pin drills to open it up. Start with a #52 wire sz. drill. Also even though several of the jetting szs. that I posted are listed as stock in you're owners manual don't assume thats whats in there, physically check each one. If you're uncertain about what which jet is which go to the Sudco website and download the schematic for the the FCR carb.
the temperature is around 5 to 20 degrees C depending on the time of day. elevation is sea level. yes i am riding while im testing. usually up a hill by my neighbor hood or riding to and from work
