Misc: Everything Else H.T. Coils
- Thread starter Bill Thomas
- Start date
Why rrun large plug gaps? The books all recommend 0.018". If there is an ignition problem reducing plug gaps is more likely to improve things if only as a temporary fix.
Plug gaps are a consequence of the type of ignition fitted. When you have a very miserably performing mag - as all classic Lucas types are with rotating coil - you will struggle on the kick starter to get a spark of 0.7 mm like on most spark plugs readily set that you pull out of the factory packing and suitable for any car engine with battery ignition, contact breaker type or electronic. With electronics you may even go for 0.8 mm gaps or more and a fat long spark will definitely help for igniting the mixture at all conditions, weak or rich.
What sort of gap you can use depends on compression as well, with higher pressure you also need higher voltage on the electrodes, else you don´t get any spark at all at the spark plug.
When you find a coil with low resistance that draws more than 4 amps you cannot use it with contact breakers as they will burn away way too fast. These coils are suitable for contactless electronics only so find another type.
Vic
What sort of gap you can use depends on compression as well, with higher pressure you also need higher voltage on the electrodes, else you don´t get any spark at all at the spark plug.
When you find a coil with low resistance that draws more than 4 amps you cannot use it with contact breakers as they will burn away way too fast. These coils are suitable for contactless electronics only so find another type.
Vic
I think BTH recommends .022 ?
Correct!
What plugs Somer. I have found that a BT-H (new electronic CDI type) does not like to fire anything colder that an NGK 6
I have an open D, which came to me back in 1976 with the C-style front stand setup and C front cowl. I agree that the coil on the side of the engine is ugly.
I mounted one of those small 12v coils used on loads of Triumph bikes. I made a simple bracket that hides the coil just above the stand system, behind the cowl. I also mounted a Dyna "points booster" under there.
https://www.google.com/search?q=dyn...8KHeCYByAQ9QEwBnoECAUQCA#imgrc=zZ2B8Z59f-is-M:
I don't know if it's available in the UK but there are lots of suppliers. With that device, the only thing that should wear on the points is the rubbing block which rubs on the cam. A little lube there should keep that in check. With the points booster, the current carried by the points is negligible. Besides that, the device is supposed to give a hotter spark because it creates a cleaner cutoff when the points open and it also automatically controls the dwell. That's the claim anyway. I can say that the bike starts extremely well and never misses a beat.
The only drawback to this is that I have to remove the coil in order to change the oil filter. It's not much of a bother.
Cheers,
Gary
I mounted one of those small 12v coils used on loads of Triumph bikes. I made a simple bracket that hides the coil just above the stand system, behind the cowl. I also mounted a Dyna "points booster" under there.
https://www.google.com/search?q=dyn...8KHeCYByAQ9QEwBnoECAUQCA#imgrc=zZ2B8Z59f-is-M:
I don't know if it's available in the UK but there are lots of suppliers. With that device, the only thing that should wear on the points is the rubbing block which rubs on the cam. A little lube there should keep that in check. With the points booster, the current carried by the points is negligible. Besides that, the device is supposed to give a hotter spark because it creates a cleaner cutoff when the points open and it also automatically controls the dwell. That's the claim anyway. I can say that the bike starts extremely well and never misses a beat.
The only drawback to this is that I have to remove the coil in order to change the oil filter. It's not much of a bother.
Cheers,
Gary