Vboost Experts Please Comment

[johnblaid]

I've been posting in another thread and searching the internet and I just did a test on my bike that baffled me.

My bike does not run the Vboost Self Test, but when I removed the air filter box and could look down into the carb area, I started the engine, warmed it up, and ran it at high rpm and I DID SEE THE SERVO CABLE PULL THE BUTTTERFLIES OPEN.

I've looked at several vboost replacments and I'm familiar with the stock wiring. I don't think I have any mods on this newly purchased 1986.

Anyone have any ideas about why the self test does not run but the servo operates when the engine is running.

 

[maleko89]

I would guess the circuit that does the self test is not operating. The circuit that "monitors" the tach signal along the gray wire is working.

 

[RaWarrior]

I would guess the circuit that does the self test is not operating. The circuit that "monitors" the tach signal along the gray wire is working.

Which is odd, since I thought they were one and the same, the little black controller box behind the left scoop. If you don't have any gadgets in there to adjust the v-boost operation, that's kind of an odd issue. But as long as it works in function, I would just run it.

 

[alorio1]

Since 1985, I have replace my controler twice. I still have both of them. I could pull the circuit board from the holder and flex it and the bike would do a self check. I thought I had a cold solder joint each time and resoldered everything on the board but never got either one of the 2 boards to work without flexing the board. You might get lucky if you find the same symthoms I described above and fix your board. But in both my cases when the self check did not work the Vboost was also on the blink.

 

[naughtyG]

As long as it works while riding I would ignore the lack of self-check on start up. It doesn't make you any faster, whereas while running it does!