Ignition

[Peter Stokes]

For the record, a 90 degree twin (Ducati) also works fine with Pazon idle sparks. It is odd to have sparks flying during other parts of the combustion cycle - I wonder what cylinder configuration would be needed for it to cause problems, if there is such a thing. A puzzle for those much brainier than me.

Best of luck - Pete

 

[Bill Thomas]

Hello Matty, Sorry I am a silly old Sod, I told you I only had 1 lobe in the dist' Of coarse it has 2. Just checked my old coils, The 12v one I used to get home with the other 6v gives a higher reading, about 10 ohms and the good 6v one 8 ish, my meter is not that good so!! To be more powerfull do I need a lower number??. Have just looked at what Howard sent me and it says you can use 2 12v coils in series, I like you thought that was wrong but unless it was a misprint !! I think I will do as you say and get a couple of coils from Rita, Then I have a spare 6 and one 12 if all goes wrong.All The Best Bill.

 

[tatty500]

Sadly, you are all right and you are all wrong at the same time!
The RITA system is strange for an electronic system as it keeps the coil primary turned on until a spark is needed. It then turns the primary off for just long enough to make a spark. This means two things:
1 the system uses just as much power at low RPM as it does at high RPM...actully more!
2 that using a double-ended modern coil will probably result in the coil melting. This is because these coils are mostly designed to have the primary turned on for just long enough to store the correct energy for a spark. These have been called "timed turn-on" and "constant energy" systems in the past.
You see, after the coil primary has been on for long enough for the slow inductive rise of current to reach the value dictated by it's resistance, keeping it on for longer just heats the coil.
If the plug gaps are kept at the normal 18 to 20 thou, probably any coils will do....but two 12v ones will use less current.

I say keep the gaps small because the available voltage to create breakdown at the plug is dictated by the transformer action of the coil (remember turns ratio and bell transformers at school?) and by the voltage that the protection device for output transistor in the RITA produces (maybe 300 or 400V). Using the coils in series halves the theoretical maximum voltage, so keeping the gap small keeps you well away from this limitation and ensures a spark in the cylinder under pressure.

 

[Bill Thomas]

Hello 500, I can't call you Tatty, It's not right!! I don't know what school you went to,Mine never did anything like this, Maybe I would have gone more often if they did !!. The thing is with the 2 6v coils the engine started so quick, It was on TT carb's then and it flew into life, I have opened the gaps up a bit thinking I would get a big spark to help starting, But you think this is wrong ?? The bad time now is after i have been stopped for 20 min', The amp meter does not seem to move so much, But after flooding then clearing the petrol out I am about to give up and it starts, Just like a bad Mag'. I wonder if the double coil is faulty, It's not very old. Thanks for the reply, Cheers Bill.

 

[tatty500]

Bill,
I cant say that larger gaps are wrong, but other problems are less likeley if the gaps -and hence the peak HT voltage -are kept small.
Its like I said, I too can be right and wrong at the same time!
Would you like to borrow a RITA?

 

[tatty500]

Bill,
I just looked out my RITA and found that I'd removed the original 3 round pin connector, so it won't be a direct swap......however if you've binned that connector too, it might be.
I've just remebered another RITA that wouldn't always start because the unit's negative feed went via the case earthing bolt on two eyelets either side of the case with a slightly corroded bolt.
TTFN

 

[Bill Thomas]

Hello 500, Thanks for the offer, But I will press on with mine for a bit, Good bit about the earth, I will have another look, I fitted an extra earth from the unit the other day, I used to like doing this type of thing but I think I have burnt myself out a bit Cheers Bill.