HD Lightning CDI problems

[YesImLDS]

After a couple months of use on the HD lightning something has gone weird. It all started out with terrible bogging at the top end all of a sudden after I fiddled with the fuel line. So first thought is to fix the fuel problems. I completely redid the fuel line with a 1/8" inner diameter barb going to 3/16" fuel line to a briggs and stratton 1/8" inner diameter petcock then continuing to the carb. The same problem continues. Maybe the jet is clogged up so I tear apart the stock carb and clean that out and the jet is clear. Checked wiring and the magneto and everything is in good shape. Spark plug isn't fouled and was switched with another with same problems. Essentially I went through everything to find out this ridiculously expensive CDI is the problem.

The HD lightning CDI was a hope for more performance on my performance build. Worked perfect for the first couple months, but never noticed anything different in comparison to the stock CDI. Now sometimes it'll work perfectly into the top end and have no problems for the next half mile then it'll bog down not having any spark at all to the point where I was thinking that I was just starving it of fuel and I'd pull in the clutch and try to get it to free-rev.

I guess what I am trying to get at is has anyone else had a problem like this? Am I over looking something by chance? I don't want to have wasted $70 on a piece of junk plastic to go back to the stock CDI that has like 5k miles on it between three evolving builds.

 

[egjsc]

Hey just read your post and because i recently went through the exact same thing down to taking my carb apart to clean all the circuits in it. In my honest opinion i believe the best way to go(reliability wise) is to build your own cdi. I was able to grab a diagram/schematic off this site and am in the process off "R and R" to make sure I order all the correct parts and build the most reliable "black box" as possible. I ride atleast 200miles a month and a lot rides on my bike to get me to where i need to be, its my only transportation at the moment. I bought a thunder cdi from gasbike (the one that has the key). Probably not the best choice but it worked great for about 3 months or 600miles before it slowly took a dump on me. It first started with a hard to start condition i.e. i had to be peddling faster than normal for the engine to fire. And it just kept getting worse till one day i had to be somewhere and the bike just didnt want to fire. I had two extra magnetos one new one slightly used and a digital multi meter i used to pin point the issue. I found out the box was fried finally. Definitely got my $30 out of it and luckly i had a brand new factory stock ignition laying around so i lucked out. So just switched out my iridium resister plug with a ngk non resister plug(i know my sp horrible) and i was good to go. So anyways im in the process of putting together my own cdi/coil. There are a few benefits going this route. Not only am i learning the circuit and possible ways to improve opon it, i will actually have components within the circuit i will beable to test periodically to check for any signs of damage or issues that may arise down the line so something like this wont happen again because i will not fill my "black box" with resin so my paying customers wont beable to test the components on the only electronic part his engine requires. Anyways thats a whole nother story and a large reason i am building my own cdi along with being able to customize my timing curve to best match my engine and modifications and riding style. Never tried it but jags cdi looks pretty darn close to good but when givin the choice to pay that kind of $$ or build my own, choose how i want it to perform, gain knowledge and still beable to take my parents out for breakfast to thank them for everything pretty simple choice for me. Hope you get everything figured out and safe riding!

With Regards,
Erick