Vboost controller

shicks16 · Apr 25, 2011

So i took the bike out today for this first time this season and let me tell ya, Sean is a miracle worker when it comes to these carbs, i still need to do a sync but the bike pulls smooth through all the gears. my next issue i am addressing is the vboost, not sure if this is a common problem with the controllers or not but when i turn the key on the vboost does not cycle until i tap the controller a few times, it then works fine for a bit but then stops working again, could this be the controller or should i go through the wiring to see if there is a bad connection? i have found 2 bad wires that broke on this thing so it wouldn't surprise me if it was a bad connection.

one2dmax · Apr 25, 2011

Bad connection. Reheat and Remelt the contacts in the main board. Glad to hear the carbs are working good for you!

Sean

alorio1 · Apr 25, 2011

Very common problem on a bike that old. I too have an 85 that had the same issue. I saw a post from someone that opend his controller up and resoldered the components that looked suspicious and he was all good when finished. The biggest obstacle I had was removing the rubber compound that it is seald in. I used a box cutter to cut away the rubber so I would have access to all components that was soldered in. Then I plugged controller back up on bike and flexed the board in different spots until I heard the vboost motor cycle. Then I had a general idea where the bad/cold solder joint was and didn't have to solder every thing on the board, just the general area that made the controller work. After I soldered everthing in that area I tested it again on the bike and it worked flawlessly. I had a controller off another 85 (parts bike) that had the same issues. I tried the same procedure on this board but failed to get the it to work, So it is a hit and miss procedure and you might not find what needs to be soldered, then again you may be lucky and get it the on the first attemp. You have to pry the board out of the black plastic holder that encases the circuit board and cut away the back side rubber compound to have access to circuit board.

shicks16 · Apr 26, 2011

thanks for all the input, going to have to try and pull it apart, its just not as fun without the vboost, and scary as hell when it decides to kick in unexpectedly.

shicks16 · Apr 28, 2011

Took it all apart today and found 8 bad solders. Just melted them a bit and plugged it in and all seems good. Thanks for the tip. Now I am just curious what to use for to seal up the circuit again