XR650L: CDI Repair Instructions

[Spud Rider]

With 13,500 miles on the odometer, the CDI unit failed on my XR650L. Having read several threads on this subject, I knew I could probably repair the CDI unit by fixing the soldered connections of the back of the printed circuit board (PCB). Therefore, I decided to repair the CDI unit myself.

I used a Dremel tool with a cutoff wheel to cut a kerf around the CDI unit as close as possible to the backside of the case. I was careful to keep the cut as shallow as possible so I could separate the case, but not grind into the printed circuit board (PCB). After I had cut through the case, I pried the back cover off the CDI unit with a flat blade screwdriver. Once the back cover was removed, I picked away the potting compound to reveal the PCB.



Using a magnifying glass, I closely inspected the entire printed circuit board, and resoldered every suspect connection. If the original solder would not make a good connection, I removed the original solder with desoldering braid, and applied new solder. I was particularly careful to examine the soldered joints leading to the 6-pin connector. I completed the repair by gluing the back cover onto the CDI unit with black, RTV silicone.



After the silicone dried overnight, I reinstalled the CDI unit in my bike, and went for a 150-mile ride. I’m pleased to report the repaired CDI unit worked perfectly.

Spud

[ONandOFF]

Hey Spudman!
Glad to hear you tackled this and it went well. I, also, repaired mine, and posted up on the XRL thread some time ago regarding my repair. I hope you don't mind if I add my saga to your thread; I did not think to start a thread on the topic myself.

The thing would just not work now and then, suddenly start working, then all would seem fine. I inspected, cleaned, and lubed all the connectors and checked all wire continuities under stress before finally deciding it must be in the CDI unit itself.

Thanks so much to Brian (techforlife) for the encouragement to do this and the information to make it easier. It would have taken a lot more time to work up the guts if he hadn't described the unit's innards for me (and then who knows if I would have cut it apart in the proper location). It's been over six months now since the repair, and it definitely started better right from the get-go.

To cut the unit open, I used a Dremel tool with a saw blade. The teeth on my saw blade were worn so it was more of a 'burn through' than a cut. But then the back didn't want to pry off; it was stuck on. After a while I decided to try a wood chisel along the edge, and that was a bear to get started. But it eventually got a corner up so I could get a finger under. I bent the back a little too much and it broke in two, but that won't matter. Then I picked off the silicone rubber from the back, mostly with my fingernails, and a little help from a pick tool, especially for the small bits.



It was during that process I noticed the wood chisel had slipped and taken the copper layer off one corner of the board. Luckily, it was just a couple of traces and no component leads! I fixed that with a couple of wires. It took close inspection to find the stressed solder joints, but there they were, cracked around four of the six connector posts and a large-wire component, a heavy inductor I presume.



Resoldering the connections on this board was different from a normal board. Because the other side was still sealed, the only way for heated gas to escape was through the hole in the board for the lead being soldered. This resulted in some interesting air bubble voids in the cooling joints, which had to be reworked. The pads for the connector and inductor seemed small for the leads, so I enlarged them by scraping off a bit of the solder mask around them. This allowed a larger, stronger joint.



Once all the joints passed inspection, I plugged the unit into the bike, and she fired right up.



After a final solvent cleanup of the board, I applied a layer of GE RTV 116, which I've had for some 30 years, and it was still good after I pried the hard stuff from the tube opening.



Put the back on, set a book on it for compression, and now it's good to go!





Then I trimmed around the edge and filled in the gaps with black automotive RTV. (I didn't get a picture of the final product, with no red showing)

Bike starts and runs like a champ now! It's been banged to the netherworld and back, and still not missing a beat!

Cheers to you, my friend!

[ONandOFF]

I hope Brian doesn't mind if I re-post one of his pictures.
I don't have truly good macro capability to show the joint failures, but Brian has some terriffic shots like this:

[aim2kill]

Excellent reference gents, thanks!

[Spud Rider]

Originally Posted by ONandOFF

Hey Spudman!
Glad to hear you tackled this and it went well. I, also, repaired mine, and posted up on the XRL thread some time ago regarding my repair. I hope you don't mind if I add my saga to your thread; I did not think to start a thread on the topic myself...

Thank you for adding your experience, and the nice photos to this thread, OnO. I hope others will also contribute their knowledge regarding this subject.

Originally Posted by ONandOFF

...The thing would just not work now and then, suddenly start working, then all would seem fine. I inspected, cleaned, and lubed all the connectors and checked all wire continuities under stress before finally deciding it must be in the CDI unit itself...

Indeed, those are classic symptoms for a failed CDI unit. There are some other symptoms that a CDI unit that is about to fail. The engine very briefly misses while you are riding. You think it might have been a strong gust of wind, or perhaps you hit a bump in the road the wrong way, but something doesn't quite feel right about the experience. However, the bike keeps running well afterward, so you figure everything is well, and hope for the best. Another symptom is your bike doesn't seem to idle as well as it did previously, and the engine doesn't run quite as smoothly as it did before.

However, once the CDI unit actually fails, the symptoms are very definitive. The engine will die, as if you hit the cutoff switch. If the bike runs when it is cold, but the engine suddenly dies after the engine is hot, and/or you hit a bump in the road/trail, it's time to cut the CDI unit open and repair it!

Originally Posted by ONandOFF

...Thanks so much to Brian (techforlife) for the encouragement to do this and the information to make it easier. It would have taken a lot more time to work up the guts if he hadn't described the unit's innards for me (and then who knows if I would have cut it apart in the proper location)...

Indeed, thanks to Brian, and others, for posting the information regarding this procedure. I wanted to add my experience as further encouragement to help others make this repair themselves.

Originally Posted by ONandOFF

...To cut the unit open, I used a Dremel tool with a saw blade. The teeth on my saw blade were worn so it was more of a 'burn through' than a cut...

I used a smooth cutoff wheel on my Dremel tool, and also got the burn/melt effect as I cut the case. However, as you noted, this method still works well.

Originally Posted by ONandOFF

... But then the back didn't want to pry off; it was stuck on. After a while I decided to try a wood chisel along the edge, and that was a bear to get started...

Indeed, it's a bit of a pain to pry the back off the CDI unit. Thanks for the tip regarding the wood chisel! I used a large, flat blade screwdriver, and lots of patience to slowly pry the cover off the back.

Originally Posted by ONandOFF

...Then I picked off the silicone rubber from the back, mostly with my fingernails, and a little help from a pick tool, especially for the small bits...

Removing the potting compound is the worst part of the repair! I employed a plastic tab used to seal bread bags, and a cheap, plastic knife as tools to help remove the potting compound from the PCB. Once again, patience is a virtue while performing this part of the repair.

Originally Posted by ONandOFF

...It took close inspection to find the stressed solder joints, but there they were, cracked around four of the six connector posts and a large-wire component, a heavy inductor I presume...

Indeed, these are the same connections that failed on my CDI unit! One must use a magnifying glass, and carefully inspect the entire board, especially the connections you mentioned!

Originally Posted by ONandOFF

...Once all the joints passed inspection, I plugged the unit into the bike, and she fired right up...

Indeed, plug the CDI unit into your motorcycle, and test it, before you glue the back cover onto the repaired unit. I bought a new tube of black, RTV silicone to glue the cover. I didn't bother to clamp, or weigh the cover to the CDI, yet everything went together nicely. I think my silicone was probably newer, and less stiff, than the silicone you had on hand.

Originally Posted by ONandOFF

Bike starts and runs like a champ now! It's been banged to the netherworld and back, and still not missing a beat! ...

Indeed, the bike runs like new after you repair the faulty CDI unit! After your electrical problems disappear, you know you fixed the problem!

Spud

[Spud Rider]

Originally Posted by aim2kill

Excellent reference gents, thanks!

You're welcome, Aim.

Spud

[Spud Rider]

Originally Posted by ONandOFF

I hope Brian doesn't mind if I re-post one of his pictures.
I don't have truly good macro capability to show the joint failures, but Brian has some terriffic shots like this:

Once again, thanks to Brian for providing this excellent photograph! Even if the solder is not cracked, repair every connection that appears dull, instead of shiny. Once you have the cover off the back, make sure you fix any potential problems before you glue everything back together!

Spud

[rotten]

I also want to thank Brian (techforlife) for assistance in troubleshooting my CDI. I decided not to fix it right away instead purchased a new CDI so I could repair the old one on my time line as a spare. Needless to say I haven't done the repair yet... But this post is bring more inspiration! Thanks!

[Kawidad]

Yes, thanks to Brian who did the swap-o-roo with my CDI and pioneered this work. And, this thread is a perfect example of DIY nature of this site that totally rock!!!

[Spud Rider]

Here are links to some of the threads I found while doing my research before I tackled this repair.

http://www.motor-forum.nl/forum/list_messages/19436//
http://www.thumpertalk.com/forum/sho...d.php?t=918809
http://www.thumpertalk.com/forum/sho...d.php?t=959174
http://www.thumpertalk.com/forum/sho...d.php?t=877754
http://www.advrider.com/forums/showt...r#post14338579

These threads contain a lot of good information; I hope you enjoy reading them.

I am strongly persuaded by Brian's theory that repeated heat cycles weaken the solder joints. I am also inclined to believe vibration is another culprit that causes the solder joints to fail. If these theories are correct, I believe my Shorai battery relocation will increase the longevity of the CDI unit.

In the stock location, the CDI unit is tightly packed in the rear of the battery "suitcase." This location does not receive any air flow to cool the CDI unit, and the CDI unit is subjected to violent movement at the rear of the frame. When the CDI unit is relocated to the airbox, the CDI unit is cooled by the high volume of air moving into the carburetor. In addition, the CDI unit is subjected to less violent movement at the center of the bike, rather than the rear of the bike.

Spud

[eeore39648]

Thanks for starting this thread!
I have had all the syptoms, mentioned here. Two days ago, the bike failed to start, I checked everything. I have been chasing this problem for about 2 months.
Last resort, banged the unit on the ground twice, plugged it in, she started right up.

Thanks, again for starting this thread.

[KyoXR]

Originally Posted by Spud Rider

Here are links to some of the threads I found while doing my research before I tackled this repair.

Spud

Ah, yes, I am so glad you posted these links, It saved me from having to search for them myself which Is what I was about to do until I saw this,
I had come across the same links in the past but didn't bookmark them on this computer, so, thanks!

[Spud Rider]

Originally Posted by eeore39648

Thanks for starting this thread!
I have had all the syptoms, mentioned here. Two days ago, the bike failed to start, I checked everything. I have been chasing this problem for about 2 months.
Last resort, banged the unit on the ground twice, plugged it in, she started right up.

Thanks, again for starting this thread.

You're welcome, Eeore.

Spud

[Spud Rider]

Originally Posted by KyoXR

Ah, yes, I am so glad you posted these links, It saved me from having to search for them myself which Is what I was about to do until I saw this,
I had come across the same links in the past but didn't bookmark them on this computer, so, thanks!

You're welcome. Those threads contain a lot of great information.

Spud

[eeore39648]

I cut the CDI open using a coping saw. I just placed it in a vice and slowly cut it open.
I barely got into the board as you will see in the pic. So, be careful if you use the coping saw.

I found 4-5 cold solder points, that I did my best to re-solder. After I was satisfied, I plugged the unit back into the bike. She fired right up. Good enough for me.
Then I put a thick layer of Blue RTV silicone on, its just what I had onhand. I smeared it even, using my finger.

Next I put the bottom back on and squished it out, and wiped off the excess.

After I get it back in the bike I hope to report back at a later time, on how it all works out.
Thanks to the contributors here and the links provided, I have confidence it will be a successful fixed CDI!