Got my spark back..woot

Well after looking over my entire bike and not being able to think of why I didn't have spark I found my weak link. After looking over the pickups and finding out they were fine I decided It had to be the TCI. I noticed it had a cover that was screwed on so I took it off just to see if maybe there was anything inside that was bad I could see. Sure enough I saw a bad spot on the board and touched it with a screwdriver and it flaked off. It was bubbled up and cracked off the board. Took a small dab of solder to fix it and now I got spark! It turns over but only runs for a little bit then stops and thats at full choke. Anything less it wont sputter. So I'm guessing its going to need a real nice carb cleaning. Also seems like that #4 spark plug didnt have gas on it when I checked them all after starting it for a second. So maybe its cutn out because of that cylinder not getn gas. Not sure but now that I know I have spark getn gas is the least of my worries. So if anyone cant find there spark problem be sure to check your TCI boards!

here are a couple pics of it before and after

 

Thats a first. You were lucky to find it and bea able to repair it. Nice job

 

Looks like something was wrong at some point. That's not a manufacturing defect or weathering, that's heat damage from something drawing too much current. Pretty impressive that the trace burned up without blowing anything else... still, you might want to keep an eye out for another TCI box - there's a good chance that whatever caused that overcurrent is still in your bike and will strike again.

What's on the other side of that square pad near the burn point?

 

Bravo!

Read this before prying the board out of the box. I realize the TCI in the link isn't the same model but it is Hitachi and probably pretty similar.

 

well when I got the bike it was in pieces so I'm not sure, he might have hooked somthing wrong up before. But before I scraped off the bad piece it just looked like a corroded part of the board that wasnt completing a connection anymore. But like you say it was maybe a heat problem. I never flipped the board over to see what it led to but it gave me spark so it must have been important.

 

if that trace was corroded I'd take a quick sec and paint over the remaining exposed areas and your repair with nail polish (or 5-minute epoxy) to ensure that it doesn't "re-corrode."

Good catch.

 

got it running ok after some fresh gas and simple carb cleaning. Needs a tune-up still but atleast it stays running now. The engine wants to stick on a rev for a little bit when you get on the throttle so its a sketchy ride, but I couldnt resist!

 

I'm a bit late to this thread but Paul is right on - a trace would not go with that big a gap with out physical damage or a good bit of heat or a lot of current.

I would be concerned about eh cause as Paul mentioned and the stress to the components.

 

it wasnt a gap like that when I opened it. I took off some of the bad trace. It was a really small fracture and the coating on the top was gone in that area. could have happend from po, or me wiring somthing up wrong when I was first putting it together. But I will keep watching it.

 

Ahh I feel better - I tested logic card for several years early in my career. What you describe is the more common failure to see.

 

oh thats good to know