Thunder Roads Magazine MO/So. IL 2018-May - Page 32

T E C H T I P S Choosing Ignition that. (These Dual points systems were the predecessor of today’s Single fire system). The Dual points single fire sys- tem was installed in the early sixties by the Harley® dealer Mother Harley® has used a variety of ignitions over the network. The factory developed the parts, but would not years. In the early days (prior to 1979) a Points & Con- install them, the dealer had to. The later developed Single denser system with some type of advance was used. Prior to 1965, advancing and retarding the ignition was a manual fire is where each cylinder fires independently of the other. The street name for this type ignition is single fire. thing controlled by the left handgrip. Many unsuspecting Crane, Dyna, & Spyke are companies that offer both souls where pitched over their handlebars attempting to kick single fire and dual fire ignitions. H-D® itself has gone to over a bike that had not had the ignition retarded. the single fire type ignition on today’s TC88. Each brand of In 1965 with the advent of electric start, automatic ad- ignition has its advantages and disadvantages. A Duel fire vance was developed. While the auto advance is very system is the same type that has been around forever and dependable, but is also high maintenance. With the points if you select one of this type, the coil that your bike currently the rubbing block can wear away, material can transfer from one contact to the other, and the advance mechanism has will usually do the job. But a single fire ignition has the advantage of better starting and reduced low speed vibra- can wear out. These things will all hurt performance if not tion. These advantages are distinct and very noticeable. Its attended to. drawbacks are the increased initial cost and the require- In late 1979 Harley® stepped into the electronic age with ment that a different type coil be purchased. an ignition from Magnavox that eliminated the points and Crane, Spyke and the Dyna 2000 are true electronic igni- condenser, but retained the mechanical advance. This was tions that are a distinct improvement over the stock H-D® a step in the right direction, but there were still some reli- module. The Dyna-S is very reliable and an improvement ability issues with this system. It was not unusual for riders over stock but requires an advance weight set-up. Mainte- to have this system removed and the earlier points ignition system installed. The problems encountered here gave Har- nance of the advance then rears its ugly head. Crane and leys® electronic ignition a bad name. It would take years for Spyke do not require an advance weight set up. Once they are set-up and timed correctly they are truly set and forget them to overcome this. In 1982 The V-fire III ignition made its debut. This system type systems. For those of you with a generator bottom end that desire is completely contained in a black box more commonly known as a module. We actually get rid of the advance unit the improvement given by lighting the fire more efficiently, J&P® offers replacements for your points circuit breaker because the module has a couple of advance curves built in. Triggered by a rotor cup and a hall effect transducer this from Mallory and Spyke to take advantage of modern day technology. system requires no maintenance. Due to the different igni- Remember that to make power there are specific things tion requirements presented by a light (Sporty) or a heavy we must do. (Dresser) motorcycle a Vacuum Operated Electric Switch 1. We can get more air (thus more fuel) in and out increas- (VOES) that can be set at different vacuum level handles ing volumetric efficiency. This is accomplished with carb changing the advance curves. Under heavy load conditions and pipe changes. the ignition is retarded. This ignition soon proved to be very 2. We can increase the quality of our ignition. This in- reliable but not the absolute best for performance. creases combustion efficiency. Note: Remember that by All Harley® ignitions that came direct from the factory getting a more thorough burn, it’s not unusual to have to prior to 1999 fire both spark plugs at the same time. One increase jet size (more fuel, more power) to take advan- twin tower coil is triggered. One plug fires producing power, tage of the improvement. and the other plug fires during valve overlap. The “street” Generally the other 2 ways to make power (Mechanical and name for this type system is dual fire. Thermal efficiency) are not practical for the street. Finally some enterprising folks said, “let’s get rid of that wasted spark” and products were developed to do just Thunder Roads Magazine 30 Thunder Roads Magazine 31