TCI circuit board is burnt

[jimmy]

I have an 81 and have been having problems that I thought were due to my carbs being too lean in the main jet range but may be from loss of spark. Its progressively run worse and started backfiring when I'd try and throttle through the rough spots. I decided to try looking at the electrical side of things and switched coils, using a coil from another motorcycle (not sure what). THe bike ran and still had the same issues and then completely died, wouldn't start at all. I charged the battery and put back the original coil and couldn't get it to start and checked the spark and it seemed very sporadic. I pulled the TCI and looked at the circuit board and it was burnt and bubbled underneath the L shaped metal plate. This may have been the cause of all my problems BUT my question is, Did the TCI slowly shit the bed, causing my problems or do I have another electrical problem which caused the TCI to shit the bed. ANY help would be much appreciated, the snow is about to fly here and I would love to ride it once with everything working. THanks

 

[jimmy]

Basically I'd like to know if there are any electrical problems that would cause the TCI circuit panel to burn like that

 

[retiredgentleman]

The TCI is not an easy thing to trouble shoot. The basic process is to eliminate everything else associated with ignition, which then can only leave the board.

There have been quite a few cases where the trigger magnet (mounted on the alternator rotor) has weaked over the years. One way to test this is to disconnect the rectifier/regulator (start with a fully charged battery) and see if the bike runs normallly. That is just an example and may not be your problem.

Use the "Search" function at the top of the page, left side. Type in something like "TCI failure". There will be lots to read and should help.

 

[Ghetto]

My current rider I bought ran like crap and had weak spark. Slapped some different triggers in there and it fixed it all.

 

[nic81xs]

my bike was doing that same thing and ended up going down the same road you are as well. replacing the TCI with the Pamco set up did the trick for me. good luck!

 

[jimmy]

Thanks for the input guys. I swapped the TCI last night and took it out for a ride, everything is perfect, better than ever. I just hope that I don't fry this one due to some other electrical issue.

 

[DirtyErnie]

Is that the L-plate with the transistor on it?

 

[jimmy]

Ya that's the one, it was all burnt and bubbled underneath it.

 

[gggGary]

You should ohm out your "replacement coils" the wrong primary resistance in the coil can overload the TCI. 2.5 ohm +- 20% is stock, lower is bad. I see the Mikes coils are 3.3 ohms