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Hello Mike - My wife has a 1984 FXRS Low Glide. Last winter she had the whole top end (top is evo and bottom is shovel) rebuilt. Every time she goes for a ride, the rear plug gets fouled. The front plug stays clean however. The bike will cough, backfire and hesitate when she tries to accelerate. We notice this more after stop and go riding around town - she has to really rev it to blow the crap out then it runs a little better. At first we thought it might be the carburetion (running too rich) but wouldn't that foul both plugs? A friend said he thought it might be the coil. Is there a quick/easy way to check if the coil is bad before buying a new one? Also, I have seen that we have a choice between single fire and duel fire coils. Is there a preference? Can you explain the difference? She is not a "hot rodder" and really babies her bike. I'd just like to get it to the point where she has no worries on long trips. I'm getting tired of chasing the gremlins around her ride. Thank you,
Dave
Answer -
A couple of questions. Are you sure the bottom end is a shovela dnthe top a EVO? I dont thing they will match up or if they do you sould have to do a lot of machine work.
Does the bike smoke when you are ridding it? What carb do you have on the bike? How many miles have you put on the bike since the top end was done?
As to the coils. The single fire coil fires just on the intake stroke, not the intake and the exhaust stroke, like the common harley. In order to install a single fire coil you have to install a single fire ignition. The single fire ignition will give you a little more performance, smoother ride and easier starting.
Let me know the answers and I can help you.
Mike
Mike - Thanks for getting back to me so quickly. First, I am sure that the bottom end is a shovel. In '83 when they switched, some Evo tops were mated to shovel bottoms at the factory. You're not the first person to ask this question and most of the folks that have worked on it are baffled by it. Anyway, no, the bike does not smoke. The carb is a Keihin. I'm not sure which model but I was told that it was the predecessor to the screemin' eagle performance line. I think it's a 40mm.
I'm not positive tho'. She has only put about 500-600 miles on it since the rebuild. Should I assume the coil is a duel fire? Is there a way to tell? Would a duel fire coil mated to a single fire ignition (or vise versa) cause this problem? Thanks again, -
Dave
PS - If you think the problem is the coil, is there a brand/model that you recommend?
AnswerSince the bike doesnt smoke and you are haveing a problem with the one cylinder there are are a couple of things to check.
Check to see if you have a intake leak, You can do this by spaying a little carb cleaner around the intake when the bike is running. If the RPMs go up then you have a leak.
Check your plug wires. A bad wire will cause the problem.
I dont think its the coil, or both plugs would foul. Same with the carb.
To see if you have a single fire coil, check the wiring. There should be three wires. one hot and two going to the ignition.
No, a duel fire coil will not work with a single fire ignition or vise versa.
Good luck and happy riding
Mike
