Resistor plug?
- Thread starter yamahonky
- Start date
Resistor plugs do NOT give a weaker spark except in old tech ignition systems tha can barely jump the plug gap. With CDI the resistor actually enhances the spark available to fire the fuel air mix. This is because the discharge time from a Capacitor Discharge Ignition is so brief. The resistor helps to stall the rise time in the spark coil and to lengthen the duration of its' discharge.
You can watch this happen if you have access to an oscilliscope.
At one of the Yamaha tech schools I have been to, they actually showed slow motion film of the ignition process happening with both cdi/resistor plug and cdi non-resistor and it was quite dramatic.
They also made the point that nearly ALL failures of CDI units is from degredation of the capacitor unit itself within the CDI and that the use of non-resistor plugs will speed up that degradation by a huge factor(a difference of gazillions of cycles).
Considering the price difference between resistor/non-resistor plugs, and the price of CDI modules, I would stick to resistor plugs.
If you are talking about the '82 yz490 listed in your profile, it shouldn't be that hard to start. I had a couple 490's and a couple 465's back in the day and they were all two kick bikes, three on a bad day. Cold, it was fuel on, enrichment(choke) on, no throttle, kick once, pop and die. Kick again, and it would pop and them idle, enrichment to half and small throttle inputs for thirty seconds or so and then enrich off and ride.
They are big engines though, and any aspect(carb, compression, ignition) being off by much will affect them in a big way as well.
You didn't say what the plug looks like when you pull it out. What DOES it look like?
Do you kick kick kick? Does it pop and die? Do you have to pull the plug and dry it to get it to start?
You can watch this happen if you have access to an oscilliscope.
At one of the Yamaha tech schools I have been to, they actually showed slow motion film of the ignition process happening with both cdi/resistor plug and cdi non-resistor and it was quite dramatic.
They also made the point that nearly ALL failures of CDI units is from degredation of the capacitor unit itself within the CDI and that the use of non-resistor plugs will speed up that degradation by a huge factor(a difference of gazillions of cycles).
Considering the price difference between resistor/non-resistor plugs, and the price of CDI modules, I would stick to resistor plugs.
If you are talking about the '82 yz490 listed in your profile, it shouldn't be that hard to start. I had a couple 490's and a couple 465's back in the day and they were all two kick bikes, three on a bad day. Cold, it was fuel on, enrichment(choke) on, no throttle, kick once, pop and die. Kick again, and it would pop and them idle, enrichment to half and small throttle inputs for thirty seconds or so and then enrich off and ride.
They are big engines though, and any aspect(carb, compression, ignition) being off by much will affect them in a big way as well.
You didn't say what the plug looks like when you pull it out. What DOES it look like?
Do you kick kick kick? Does it pop and die? Do you have to pull the plug and dry it to get it to start?
- Thread starter
- #3
Plug looks a little dark, I know I have the jetting rich, I turn the gas on, choke on, couple kicks, a pop, couple more kicks, fires, dies, no choke, couple more kicks and a another loud pop :| and it fires up un runs good. when its warm, it takes about 3-10 kicks :bang: I think I should raise the clip to make it leaner, no hesitation and alot of power anyway. the ignition is good and it has a new top end with no leaks and tons of compression. I carry an extra plug with me in case it won't start and with a new plug it starts about twice as fast. Thanks for you help :)
Have you checked the reeds? If they are cracked, frayed or don't seal against the reed cage then it will be hard to start. (I'm assuming that bike has reeds)
- Thread starter
- #7
I raised the clip today inbetween the very top and middle notch, I took it out for a ride and holy crap :yikes: its got alot more power. Didn't foul a plug either. I rode a huge wheelie in 4th gear over the top of this hill. Thanks for everyones help, yamahonky :aj:
