[Treetrans]

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Hey folks new problem developed on my 78 restoration . It was running great, I put about 200 miles on it and Saturday it began shutting down on at least two cylinders . Had to be two, big time loss of power and in traffic 55 mph it would hold speed if I dropped two gears but was hard to get going. A minute would pass and then it would pop back on and go ripping down the road only to happen again down the the road. so I limped home on and off power. and suspected a coil as two cylinders would drop together . Don't think carbs or fuel issue would cause that. friend had a coil set off a crashed gl he bought and one coil has a crack in hard plastic shell . It checked out ok as did my old ones. I think mine was failing when hot . I siliconed the cracked coil and mounted them up . Rode a short way and so far so good .. Anybody run a coil with a crack does it work ok ?? I know I could put the good coil of my two in but the connector plug would have to be dismantled and taped up and all to separate them. I have Dyna ignition and the Ballast resister has the a coil scabbed onto it to reduce it further. I would try 1100 coils but the connector is different and the not sure about the 1.5 ohms resistance I need for the Dyna as per Randakks tech. page .. Thanks Randakk
[align=left]Electronic ignition like Dyna-S[/align] [align=left]OEM coils [/align] [align=left] Follow electronic ignition manufacturer's directions regarding retension or replacement of OEM ballast.
Generally, Dyna will want you to end up with a ballast resistance value of 1.5 ohms. This has been accomplished in 2 different ways. Some Dyna installs have provided a "piggyback" resistor to be used in conjunction with the OEM ballast to provide the correct resistance value.
Other Dyna installs have provided a replacement ballast calibrated to 1.5 ohms. In this case, the OEM ballast is omitted.
Just be sure you end up with approximately 1.5 ohm total resistance.
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[sandiegobrass]

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Becareful substituting GL1100 coils.. they are 0.5 ohm (not 1.5 ohm) and will draw far too much current without proper ballast... as for the crack, if it is working properly, that is all that matters.. eventually, however, oxidation and heat will get to it too.. Doesn't Dyna have new ones that work??

 

[morriscatt]

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sandiegobrass wrote:

Becareful substituting GL1100 coils.. they are 0.5 ohm (not 1.5 ohm) and will draw far too much current without proper ballast... as for the crack, if it is working properly, that is all that matters.. eventually, however, oxidation and heat will get to it too.. Doesn't Dyna have new ones that work??

So SB, still trying to learn more about 1100 coils for my 1000. Considering above, can I add 2.5 ohm of ballast resistance and still use them??
Rick Treetrans may be interested in this too.. Not trying to steal thread..

 

[Treetrans]

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Thanks Sandie, and Morrissey and I Had a pm about his 1100 coils he is selling earlier. I had thought I would have a fit issue with 1100 coils and now have heard elsewhere that the horn on the air box intake needs to be sawed off to accommodate aftermarket coils on the 78. I notice that my intakes is only about a 1/4 inch from the piggy back resistor coil added when the Dyna was put in now. I hate to think what would go down if that super hot resistor were to rub against the air box intake and short. I didn't notice that 1100 coils run .5 ohms resistance. that does tend to further complicate and add cost which I am not in favor of right now. Well my old friend from the Classic Wing club donated a pair of stock coils from a crashed bike he bought and I silicone'd the crack. If this proves to have been the problem one of my coils should still be good they both test out fine cold I can heat them up and see which one goes bad and replace the cracked one with the my better one. Used parts don't bother me I ride local and most of the 30 year old GL bikes are running around with original coils anyway. If I had the cash I would just throw on new ones.

 

[sandiegobrass]

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morriscatt wrote:

...So SB, still trying to learn more about 1100 coils for my 1000. Considering above, can I add 2.5 ohm of ballast resistance and still use them??
Rick Treetrans may be interested in this too.. Not trying to steal thread..

I don't know if adding resistance will solve all the problem or not.... These very low resistance coils (and others like it) are designed for capacitive discharge systems (the "spark box" is the cd part).. If it were just a points sytem, I'd say it won't work very well.. but I don't know the Dyna system, so I can't say..it might be a cdi.

Edit: I wanted to add that having a crack in the case of the coil doesn't initially affect the electrical performance.. just exposes it to the elements which will eventually degrade the insulation and probably decrease the heat dissipation... and these coils are not oil filled, so nothing to leak..

 

[morriscatt]

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Thanks for your reply SB, my Dyna box is at Dynatek for repair/replace as I write. I will email Dynatek about my Dyna status and ask about .5 ohm coils with 2.5 ohm Ballast resistor will work.

 

[Keystone742]

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Just an after thought...Last year whileon a 3 day ride I discovered I also had a cracked coil. I discovered it on a wet morning. I was able to get to it without to much difficulty, and used expoxy glue to cover the crack. It worked! I finished the ride and actually rode the rest of the season before I took the time to replace it. It now sits on the shelf out in the barn as a spare if I should ever need it again.

 

[Treetrans]

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Thanks Keystone I am going to have to make do right now, I have some JB Weld I can mix up an spooge in the crack. I will try to make it that way for now. And SB great electrical guidance I was afraid it might arc out and short on the frame. I have the old ones I will heat test and see if one is good and get that in place of the cracked one ASAP.

 

[brianinmaine]

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Some black ABS glue might work well also, although I don't know for certain if the plastic is ABS or not.

 

[Broke Winger]

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If a coil has a crack in it, it's junk. It will leak,not oil butspark.

I have a set of stock coils I just pulled off a '77.The bike had carb issues but seemd to fire on all four. $15 and I'll ship them to you.

 

[Treetrans]

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Hey Broke whats new. I did silicone the crack and that might keep out water but I would rather replace that one. I will take you up on the coils. I can meet you again! This time I will come further north. I will PM.

 

[sandiegobrass]

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If a coil has a crack in it, it's junk. It will leak,not oil butspark.

Eventually, yes... as the wire insulationbecomes damaged by the elements, but not necessarily or immediatelyso... the coil wire has an insulation coating that eventually becomes damaged by exposure..

 

[Treetrans]

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I agree SB I am ok using it interim but it will definitely fail eventually. I think i am going to take a ride up to Milwaukee and buy the spares from Broke Winger.

 

[Treetrans]

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Ok gents I met up with Broke Winger and bought his 77 coils. I removed and tested the cracked coils with multi tester. The coils showed value of 15200 ohms without plug caps. Then wifes hair dryer provided heat and tested again the readings jumped up and down way up way down out of specs . So I tossed them. I then tried the ones Broke supplied, they held the spec throughout the heat . So I clipped off the bullet connectors and installed the 78 6 prong plug connector by solder and dielectric grease and taped well. Then to check resistance on plug caps can only say JUNK.. Tossed them and ran up for a set of NGK XD05F caps , installed all and took it for a 20 mile ride . No Problems. Last evening I planned to ride to local cruise night. warmed it up and waited for a friend. Then we took off. I made it about 100ft and dropped two cylinders. I continued ,Pissed off ,and it soon popped back up to all four again. Made a light or two and got out to the HWY. Soon it dropped two and putted along and fired back to 4 again. On off all the way and runs great when its on.. I am at a loss I have Dyna ignition so points are out. the coils are now testing out with new plug caps and plugs. Carbs all re done with Randakks carb kit. Last week the fuel pump was dripping so we put on a new one. Their was some rubber flaking in the old pump diaphragm. All new filters fuel /oil /air/, New timing belts.I can't think of any other reason two cylinders selectively could drop. Mostly anything else would stall the whole engine like a electrical short?? Ignition switch or shut off switch. Even the carbs would tend to cause bike to run badly all the time not on off. Baffled. Thanks for any ideas you might have.