bogging - backfire - funky RPM gauge

[86venturejay]

my 86 is being cranky again...

 

Went to start her up and she didn't want to start. Finally started but wasn't running so hot. Noticed the RPM gauge was at dead zero and not even twitching. when I rev it... the RPM gauge takes a second but finally comes up. I took it for a quick spin and even at higher speeds it's bogging with out much power and also when it does bog... the RPM gauge goes back to zero like the bike is off. Then the RPM gauge will come back and it runs normal again. Kinda goes back and fourth from running fine to no RPM's and not running fine.

 

HELP!!!! my baby is sick! hahaha... thanks in advance!

[bongobobny]

The issue is most likely water inside your TCI case, or corrosion on one of the connectors. The tach gets it's pulses from the #2 ignition pulse to the coil. Take away the ignition pulses, it runs like crap if at all.

 

You should remove your TCI and unscrew the cover then bake it in the oven at 225 - 250 degrees for an hour. Clean the connectors, and remount the TCI on top of your airbox...

[mbrood]

Although it's a little more involved... when you have the back cover off, if you see any white or grey corrosion, you are money ahead to desolder the edge connectors and lift the board out and inspect around the main power diodes. Unless yours has been replaced or repaired, you will find grey and blue glass diodes that were prone to break down, taking THAT output transistor with it and that cyclinder quits working... replace the 8 with 1N4001 (family) ceramic and be done... clean up any other corrosion and then consider relocating the TCI to above the aircleaner, the wires route up there pretty easy.

 

Note the corrosion on the two at the top left between the two power transistors...

 

http://www.bergall.org/temp/venture/tci/tci2.jpg

[86venturejay]

wow... thanks for the great info. I'm ok at re-soldering so I think I should be good to go after a little work here. Silly Question.... Where is the TCI case?

[Trader]

The TCI is above the front cyl. beside the coils. A bit of a pain to get to.

It's real easy to relocate to the top of the air box. The wires will allow it to be moved. You might just have to trim off one of the screw tabs to allow it to move far enough forward so the false tank lid will sit down properly.

 

I put a strip or 2 of velcro to hold mine in place. Easy to flip out of the way if I need to get into my airbox.

 

Less heat and water exposure in there

[friesman]

The TCI is above the front cyl. beside the coils. A bit of a pain to get to.

It's real easy to relocate to the top of the air box. The wires will allow it to be moved. You might just have to trim off one of the screw tabs to allow it to move far enough forward so the false tank lid will sit down properly.

 

I put a strip or 2 of velcro to hold mine in place. Easy to flip out of the way if I need to get into my airbox.

 

Less heat and water exposure in there

 

Correct me if I am wrong, but I think taking the battery out and removing the battery box helps make it easier to get to?

 

Brian

[bongobobny]

Yes it is!