Dual output coil with points?

kismetologist · Posted: October 18, 2007, 10:27 am Post subject: Dual output coil with points?

Anyone ever use the dual lead single coil/dual-lobe points cam setup from MikesXS.com?
I like the idea of having both cylinders firing in exactly the same spot. With the stock points setup, I can never get them closer than within a few degrees of each other. (Seems it might have the added bonus of keeping plugs a little cleaner because they fire on the exhaust stroke as well as compression stroke?)
I was thinking of replacing the original coils with NOS, but the single coil/points cam package is only a few bucks more than 2 stock coils. Cheap upgrade? or no advantage?
(Not interested in going to electronic ignition... too many $$$s)

5twins · Full Member Joined: Aug 05, 2006 Posts: 1616

I'm hoping for some feedback on this as well. I like the idea. My old '70s BMWs all run this set-up but use 2 separate 6 volt coils wired in series. Hmmmm ..... wonder if they'd fit under the XS tank - then I'd only need the cam.

What I don't like about Mike's coil is the plug wires appear to be part of it and can't be easily replaced. I prefer a plug wire I can replace as I like to run colored silicone ones.

KYLEPRESTON

I actually found the 2 lead single coil from a 250ninja fits and has longer wires so I am running it The unit itself is a little smaller than stock But I had to build a bracket to fit my tx under the tank.
you never know just try it.

kismetologist

Hmmm. Good points, both. (No pun intended) Do you notice a difference in how it runs with single vs. dual coils? Was that single coil stock when it was on the Ninja? A quick check of ebay just came up with (lots of) hits for tandem coils for the Ninja 250. Good idea considering other bikes, though. As far as compatibility, what does the primary resistance value mean? Stock coils from Mikes are 4 Ohm, the dual-lead coil is 4.5 Ohms. How close does it have to be to work properly?

5twins · Full Member Joined: Aug 05, 2006 Posts: 1616

I just did an eBay search as well and all I'm getting is single coils with one lead for the 250 Ninja - they run a pair just like the stock 650 set-up.

KYLEPRESTON

I AM FORTUNATE ENOUGH TO KNOW SOMEONE WITH A SALVAGE YARD SO I JUST RUMMAGE AROUND.

kismetologist

That's the way!

beys

kismetologist wrote:

Anyone ever use the dual lead single coil/dual-lobe points cam setup from MikesXS.com?

I got mine from Rüdiger Paustian and as he and Mike do a lot together, I think it's the same kit.
There is nothing to say about, I put it on in spring and it runs since without ever having looked after. No problem at all.

5twins wrote:

What I don't like about Mike's coil is the plug wires appear to be part of it and can't be easily replaced.

If its the same coil as Rüdiger's it comes with the wires apart, so you can replace it, if needed.

Retiredgentleman

Just thought I would comment on dual output coil.
I installed an Accel single coil/dual output with my points system and it works really well. The coil has 3.5 ohms primary and I have a 1.35 ohms ballast resistor in series. I have the 2 sets of points tied together in parallel. It produces a nice fat blue spark and hurts like hell when I get shocked by it! Bike starts perfectly every time using the starter motor. Spark plugs are a nice tan colour.

kismetologist

I'm not much of an electrician. How would I wire two single coils in parallel? (5twins mentioned single coils wired in series on the Beemers. How's that look and do both schematics work equally?)
From what you say, seems I could just get the two-lobed points cam, disconnect one set of points and rewire my existing coils, no? It wouldn't give me a stronger spark than I have now (not sure I need it) but it would be at least a test of whether it makes a difference timing-wise.

5twins · Full Member Joined: Aug 05, 2006 Posts: 1616

I'll have to admit, I'm interested in this as well. I'd love to do the single points set-up but not with Mike's fixed plug wire coil. Retiredgentleman, can we get more info on that coil you used? Is there a 4 or 4.5 ohm one available that wouldn't need the ballast resistor? Adding the resistor reduces output. I'm going to research some of the 4 cyl. Kaw ones. I think that prior lead from Kyle was wrong. No Ninja 250 I looked up had them. Dual output single coils only came on the 4 cyl. models.

Retiredgentleman

The coil I use is called "Accel 2 Cylinder 1 Coil Non-CDI # 140403S".
I bought it from www.mawonline.com for $67.95 plus shipping; price includes high quality spark plug wires and boots.
Primary 3.5 ohms Secondary 10K ohms.
This coil is rated at 30,000 volts...................stock yamaha coils rated at 10,000 volts. The ballast resistor probably reduces the voltage to 23,000 to 25,000 volts, but that is still much hotter spark than stock. You could try running without the ballast resistor but it might burn the points.
I've driven 1100 KM this summer and I'm real happy with this ignition. Bike starts instantly everytime using the starter motor.

5twins · Full Member Joined: Aug 05, 2006 Posts: 1616

Thankyou RTG. Now about this resistor ..... is this something you can just buy at Radio Shack or something? Or is it right from the coil company?

Retiredgentleman

Bought the ballast resistor at NAPA Auto Parts. Its got a part number "ICR23" on the box it came in. I think it was for a chysler car. I wanted a 1 ohm but the 1.35 ohm was the closest they had.

muleman · Full Member Joined: Mar 08, 2008 Posts: 17

ok question i got is i have the same accel coil as above, 140403... to run one set of points is all i have to do is put a dual lode point cam in and just run the one set of points??? unhook the other??? without the ballast resistor do you think i will do any damage, thanks.

Retiredgentleman · Posted: March 26, 2008, 1:04 am Post subject: Re: Dual output coil with points?

I'm not real familiar with the dual lobe set up...................but yes it should be simply install dual lobe cam and disconnect either set of points. Just use 1 condenser.
Give it a try without a ballast resistor and then monitor for excessive sparking and/or wear on the points. Let us know how it works. Just remember that the single set of points is now doing double duty i.e twice the wear of a dual points set-up.

jimmythetrucker · Full Member Joined: Mar 12, 2008 Posts: 1283

Tuning stock dual-point systems -- for me -- was a lot easier with a dwell- tach. Proceedure:
1) Gap both sets of points with a feeler gauge.
2) Hook a dwell-tach to the first set of points.
3) Start the engine and note the dwell reading.
4) Stop the engine and hook the dwell-tach to the second set of points.
5) Start the engine again and adjust the gap on the second set of points to make the second dwell reading match the first dwell reading.
6) Stop the engine and unhook the dwell tach. Then hook your strobe light to the number one plug wire.
7) Start the engine and set the timing on number one cylinder.
8) Set timing on number two cylinder. Poof! You're done.

For those who don't understand -- A "dwell" reading is the amount of time, measured in degrees of crankshaft rotation, that the breaker points are closed. When you change the point gap, you change dwell timing (and ignition timing) because you move the rubbing block closer to or farther from the distributor shaft, which means that the points will open either sooner or later (relative to crankshaft position).

Gapping points with a feeler gauge is therefore imprecise because -- no matter how good you are with a feeler gauge -- you'll never gap two sets of points precisely the same. Without some amazing luck, it is virtually impossible. But when dwell readings from both point sets are identical, both point sets are gapped exactly the same. This helps get peak performance from your OEM, dual-point ignition.

xsjohn · Posted: March 26, 2008, 10:26 am Post subject: Re: Dual output coil with points?

Been looking into this for my riding buddy’ 79…..think we have found a better way for him because he doesn't tend to the points like he should...first you want to keep the mellow factory advance curve which is the factory advance rod and weights…the single points sounds good for easy timing….and you would keep the factory advance curve which is good…...many of the add on electronic ignitions go to full advance at 2500 rpm….terminal chain snatch and jerky….very undesirable to say the least for a cruising bike….

Pamcopete has designed and sells an electronic ignition for 79 bucks that uses the factory advance…all you would need is a dual output coil and have a better spark than the points and keep the factory advance curve… and no adjusting……….

pete @ yamahaxs650.com

xsjohn

5twins · Full Member Joined: Aug 05, 2006 Posts: 1616

There is an actual dwell value for the 650 given in the shop manual. It is 93' +/- 5', or 88'-98'. On a dual points 650, using the 4 cyl. scale on the dwell meter would give readings of 22'-24.5', 1/4 of that value. Switching to a single points set-up should give readings of 1/2 the value, or 44'-49'. The meter reading is inversely related to the actual gap. In other words, a smaller reading indicates a larger gap.

There should be a step #8 in jimmy's description. After setting the timing on the first set of points for the right cylinder (mounted on the main backing plate), you must check and set timing for the second set (left cylinder) mounted on the small half plate.

I will be doing the single points conversion in the next few weeks and will report back with the results. I think this is going to become a very popular mod.

xsjohn · Posted: March 26, 2008, 12:13 pm Post subject: Re: Dual output coil with points?

5twins....Would less dwell mean less spark with 2 lobes...more dwell time I thought means more spark...?...electronic ignitions do kick ass for spark......

Since my bike is already factory electronic and the advance curve is tolerable I think I will take Roys advice and get the high output coil from Mikes and see what happens........even more spark on mine can't hurt......

xsjohn

5twins · Full Member Joined: Aug 05, 2006 Posts: 1616

Well, in an extreme case, I guess that would be true, and it wouldn't matter how many lobes there were. Less dwell would mean less time that the points were "dwelling" in the closed position, allowing spark energy to build in the coil. That energy is released and the plug sparks the next time the points open. If the points gap is too large, the points stay open longer, leaving less time for the coils to build the next charge.

John, I would shop eBay for a nice aftermarket Accel or Dyna coil. The Harley ones will work and are a dime a dozen there.

xsjohn · Posted: March 26, 2008, 12:58 pm Post subject: Re: Dual output coil with points?

Would they mount under the tank like the stock one.......never cared for having a coil mounted where it could be seen or all the funny colored wires......kinda like butt crack....looks ok on some but not on others if you know what I mean.....

Still think Pete's electronic with the stock Yamaha advance curve would be a good investment......that's the way I would go for 50 bucks more......and twice the spark....

xsjohn

5twins · Full Member Joined: Aug 05, 2006 Posts: 1616

Yes, you should be able to fit it in the original location. On mine, some slight relocating of a couple of the components (turn signal flasher and self canceling unit) will be necessary, but I'm sure I can make it fit.

Electronic ignition DOES NOT give twice the spark. It merely regulates it electronically, eliminating the need to set timing or service an advance mechanism. Spark energy will depend on the output of the coil it's regulating. That's why I recommended those aftermarket ones, they're higher output than Mike's Taiwan special. Just match the primary resistance to your stock one. For electronc ignitions, that's something like 2.5 or 3 ohms. For points, you want about a 4 ohm or higher or the points won't last long.

Over the years , I've had both points equipped and electronic ignition bikes. A points bike never let me down but an electronic ignition model did once.

lar55 · New Member Joined: Jul 07, 2007 Posts: 9 Location: ill

Take a look at blacksmithbilly. He's got a duel car type coil on his . ,I have seen these on onan twin cylinder motors. I would like to do the same thing on a my XS and a Honda 450 ....

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Yamaha xs650