not sure where to post this so here it goes . i have a 98 fxds been running fine with ultima single fire setup coil and module standard carberator im pretty savy backyard mechanic ive always fixed my own vehicle for many yrs but this has me stumped about couple weeks ago bike little hard to start then when it did only seem to hit one cylinder so i reved up and at above 2k rpm the other kicked in lowered and it went out again so reved again it kicked in and after few seconds it seemed to stay working but every time i would start had to do this a week went by and then it got worse would only work above 1500 rpm so i pulled plugs looked fine put them in the wires and held against head bolts and cranked bike both had spark so put in and started bike sparayed carb cleaner by intake to head seal area both of them and the carb side also no aparent leak took carb out and changed them anyway had a set of seals cleaned carb and still no difference so i caint understand why its doing what it doing if it were fuel it would be both cylinders so i am thinking it has to be in the sparke but i have spark and compression wouldnot go in and out it would just fail im thinking coil but i dont trust test cause in past ive had test perform good and when i finaly came back to conclusion the problem had to be coil i would remove and find the backside had cracked and ozed out inside stuff so the test i caint trust if anyone has knowledge of this symptom and cause please respond . i just caint figure out how have spart at plugs both but when try to start the front cylinder wont fire and also i put a test ligh to the rear spark plug when engine runningg only one cylinder and it killed but when i put on front it made it fire but then bike kills so weird