Hello guys; I have a 2006 Road Star 1700 that I put exhaust on and a BAK, Dyna 3000, ported intake, Barons jet kit with 67.5 main jet, a Dyno Jet 37.5 pilot needle, PMS 1 turn, idle at 910, Barons needle on the 4th groove. The bike runs 100% better than before I did all the performance mods, and it is perfect with one hiccup or cough so to speak. When I come to a 90 degree turn (like a city street corner) and make the turn and get back on the gas the bike will cough. Or sometime when I am starting from a dead stop it will cough. This is intermittent doesn't do it every time and usually only after is full y warmed up. There is no popping through the exhaust at all, and other than this the bike is running great. When I blip the throttle it does not cough, and I have looked at the squirt when I blip the throttle and it looks like it is squirting when the throttle blade starts to open, but it is kind of hard to tell when the bike is running, can this be checked when the motor is off? My question is do you think it might the accelerator pump timing and or duration? or maybe the needle needs to be moved up a groove (3rd)? if it's the pump I haven't seen how to adjust the timing screw. I have seen that most people swap the nut on the Duration screw to the bottom side of the bracket and adjust the screw all the way down to get the least amount of duration they can. But I haven't seen anything on the timing screw. Thank you for any advise or input you guys might give.
GUYS,1ST THINGS 1ST!!!!! /LOL!!!!!!
The OP said the motors running fine accept for having a pop back thru carb
once in a while when applying throttle coming off idle or when hitting throttle at low speed and thats it.
So with that in mind when having an off idle carb cough/pop back thru carb coming off idle you " should not go into changing pilot jets " etc right off the bat before 1st ensuring the following are working and or adjusted properly which were specifically designed to reduce or stop off idle stumble when applying throttle!
* ENSURE ACCELL PUMP IS WORKING WHEN YOU MOVE THROTTLE & FIX IF NOT WORKING.
* ENSURE THE ACCELL PUMP STARTS TO SQUIRT FUEL THE SAME EXACT MOMENT THE THROTTLE PLATE
STARTS MOVING WHERE YOU TWIST THE THROTTLE AND IF NOT ADJ TO OBTAIN THAT.
* ALSO MUST ENSURE IDLE SPEED 900-950RPM PER YAMAHA SPEC WHICH MANY GUYS HAVE SET TOO LOW WHICH
IS AN ISSUE FOR A LRG CARB'D V-TWIN COMING OFF IDLE ADDING TO POPPING BACK THRU CARB ISSUE TOO.
* WITH MOTOR WARMED UP AT PROPER 900-950RPM IDLE SPEED ADJ PMS SCREW FOR BEST HIGHEST/SMOOTHEST IDLE SPEED.
* ENSURE PLUGS ARE IN GOOD COND & GAPED PROPERLY TOO.
* ENSURE THE PLASTIC END CAPS ON PLUG WIRES ARE ALL TIGHT WHICH IS AN ISSUE AT TIMES ON R*.
* ENSURE AIR AND FUEL FILTERS ARE BOTH CLEAN & IN GOOD COND NOT NEEDING TO BE CHANGED.
Its only after you ensure all the above is done as i suggested that if the motor still spits back fairly often when coming off idle when applying throttle at lower engine speed thats when you should get into recalibrating carb via pilot jet,etc and not the 1st thing you.
Yes you can fatten up lower end more with dif pilot ETC to fix off idle stumble but doing that feeds the motor with additional fuel all the time WHICH it may not need .
Doing that over time/miles equates to more fuel used that's maybe not required costing more if the off idle stumble is really caused by improper acceL pump adj or if its not working along with too low of an idle speed & too lean pms setting etc.
And another thing to keep in mind even when you have the carb dialed in properly that these lrg carbed v-twin motors will still spit back at you once in a while so if your chasing a A couple spit backs thru the carb in a 6-8hr day of riding i'd say that's not bad at all and to no go nuts trying to chase that down.