I have a U-built custom bike with aftermarket ignition. My problem is an occasional misfire with a backfire out the pipes during hot weather, this problem does not occur when the temp is below 85 degrees. The ignition module is Headquarters with a single fire, single plug system going through twin Dyna coils. All the wiring is good and connections are tight. At first I thought it might be the module so I rode with the cover off but it still misfired. Some one suggested it might be the coils getting to hot. Anyone have this same problem or any suggestions would be appreciated!
Thanks RT in Vancouver
bigwater 02-28-2007, 05:15 PM My first question would be is this a "one shot" misfire, ie: a single stroke that fails to fire, or is it several strokes in a row?
A single stroke failing to fire could indicate a timing/compression/fuel/spark issue whereas a series of failures is more indicative of a mechanical problem such as a valve giude that is slightly mis-seated. A series of failures would usually follow a pattern, such as it only doing it when you get on it hard, or cruising at a specific RPM.
Give us a little more details about the setup. Motor make/model, compression, lift, fuel, etc. There are a bunch of wrenches in here, and between us all we've probably seen almost every problem you could imagine.
Does it actually get above 85 in BC???
squid 841 02-28-2007, 07:24 PM I have a U-built custom bike with aftermarket ignition. My problem is an occasional misfire with a backfire out the pipes during hot weather, this problem does not occur when the temp is below 85 degrees. RT in Vancouver
It gets above 85 deg in Vancover?!!?!?!?!??!:wow:
Yes it can get over 85 F in the southern parts of B.C. usually late July early August.
The engine is a custom 96 inch, 9.8-1 comp, 10,000m, plugs are clean-no colour, Headquartes mild cam. The misfire is usually a single but occasionally a series of three spaced apart. It occurs during low to medium speed cruise or mild acceleration. This started during my ride to Sturgis last year when it was HOT but the ride back when the weather turned cool it never occured. Any info or suggestions??
Rory
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My first question would be is this a "one shot" misfire, ie: a single stroke that fails to fire, or is it several strokes in a row?
A single stroke failing to fire could indicate a timing/compression/fuel/spark issue whereas a series of failures is more indicative of a mechanical problem such as a valve giude that is slightly mis-seated. A series of failures would usually follow a pattern, such as it only doing it when you get on it hard, or cruising at a specific RPM.
Give us a little more details about the setup. Motor make/model, compression, lift, fuel, etc. There are a bunch of wrenches in here, and between us all we've probably seen almost every problem you could imagine.
Does it actually get above 85 in BC???
aleykat271 03-06-2007, 11:16 PM Hey BW I was wondering the same thing!!!! about it getting above 85??..lol....BW"S right the more info you can give us the better the problem can be diagnosed!!!:moped: My first question would be is this a "one shot" misfire, ie: a single stroke that fails to fire, or is it several strokes in a row?
A single stroke failing to fire could indicate a timing/compression/fuel/spark issue whereas a series of failures is more indicative of a mechanical problem such as a valve giude that is slightly mis-seated. A series of failures would usually follow a pattern, such as it only doing it when you get on it hard, or cruising at a specific RPM.
Give us a little more details about the setup. Motor make/model, compression, lift, fuel, etc. There are a bunch of wrenches in here, and between us all we've probably seen almost every problem you could imagine.
Does it actually get above 85 in BC???
aleykat271 03-06-2007, 11:26 PM Rory...What kind of carb are you running?? Your plugs,if it's running with the proper fuel mixture should be a light tan.Could be something as simple as,how you have your fuel lines routed to the carb,and do they have heat shields on them? I have a feeling your going to tell me you have a Super "G" S&S Carb!!!You say you have no color on your plugs,the problem could be with your jets,not enough fuel,and when it's hot you are getting LEAN MISFIRE"S!!!...:moped: Yes it can get over 85 F in the southern parts of B.C. usually late July early August.
The engine is a custom 96 inch, 9.8-1 comp, 10,000m, plugs are clean-no colour, Headquartes mild cam. The misfire is usually a single but occasionally a series of three spaced apart. It occurs during low to medium speed cruise or mild acceleration. This started during my ride to Sturgis last year when it was HOT but the ride back when the weather turned cool it never occured. Any info or suggestions??
Rory
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The carbs are cv with a Headquarters kit in, the plugs are not dark [rich] or white [lean] they are a light grey. The misfire must be electrical as it is a single misfire not a leaned out hesitation or stumble. Anyone out there have similar problem with their module or coils?
Rory
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