Hobie1dog Posted April 2, 2007 Share Posted April 2, 2007 I noticed that there are 4 ignition coils on my 97. My son's CBR has ingition coils that have 2 spark plug wires out of them. Why couldn't they have made the VFR's with only 2 coils? Link to comment Share on other sites More sharing options...
turtlecreek Posted April 2, 2007 Share Posted April 2, 2007 I noticed that there are 4 ignition coils on my 97. My son's CBR has ingition coils that have 2 spark plug wires out of them. Why couldn't they have made the VFR's with only 2 coils? are educated guesses allowed? 1. they could have, but for greater flexibility of timing when each cylinder fired, they used independant coils like the use on motogp bikes. 2. the crank shaft is made such that the cyclinders are never 180 degrees out of phase, thus you can't fire 2 plugs simultaneously in the 'wasted spark' config. 3. i have no earthly idea. while 3 is true, 1 or 2 might be also.... Link to comment Share on other sites More sharing options...
Member Contributer Stéphane Posted April 2, 2007 Member Contributer Share Posted April 2, 2007 The CBR fires every 180˚, so one coil fires into 2 cylinders at the same time: one in compression and one in exhaust (called wasted spark). The VFR has a very different pattern: see the post in 6th gen - Big (enough) Bang - for more details Link to comment Share on other sites More sharing options...
Hobie1dog Posted April 2, 2007 Author Share Posted April 2, 2007 The CBR fires every 180˚, so one coil fires into 2 cylinders at the same time: one in compression and one in exhaust (called wasted spark).The VFR has a very different pattern: see the post in 6th gen - Big (enough) Bang - for more details That's what I figured. Thanks Link to comment Share on other sites More sharing options...
Member Contributer vfrjim2002 Posted April 2, 2007 Member Contributer Share Posted April 2, 2007 I noticed that there are 4 ignition coils on my 97. My son's CBR has ingition coils that have 2 spark plug wires out of them. Why couldn't they have made the VFR's with only 2 coils? are educated guesses allowed? 1. they could have, but for greater flexibility of timing when each cylinder fired, they used independant coils like the use on motogp bikes. 2. the crank shaft is made such that the cyclinders are never 180 degrees out of phase, thus you can't fire 2 plugs simultaneously in the 'wasted spark' config. 3. i have no earthly idea. while 3 is true, 1 or 2 might be also.... Actually, I think a variation on 2 is true. The VFR uses a 180 degree crank. This combined with the "V" configuration prevents the use of dual lead coils and their attendant waste spark at the top of the exhaust stroke that is common practice on inlines. Meaning??? You need 4 coils and a way to trigger them. Link to comment Share on other sites More sharing options...
Guest matt_c Posted April 2, 2007 Share Posted April 2, 2007 This is one more reason why V-fours are more costly to produce. Link to comment Share on other sites More sharing options...
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