CDI box question......

[srxtriple]

I have a 99 Vmax 500 which will idle fine but when given throttle sort of falls on its face. Can a bad CDI box cause this?

 

[sleddineinar]

Sounds like the carbs are dirty. Pull the carbs off and clean them especially the jets, probably a plugged pilot jet, make sure you get all the little holes cleaned. There are very good write ups on cleaning the carbs in the tech pages.

 

[srxtriple]

I have had the carbs off 4 or 5 times already. very clean as far as i can see. New jets, checked compression, checked vaccum line to fuel pump.

 

[yamaha06]

I'v been having the same problems with my sled to, but anyway i pulled of my coils and took them to the dealers to get checked and apparenty they were all pretty dead

 

[T.S.U.Filmz]

by pass your t.o.r.s and try that i bet it want bad.

 

[yamaha06]

Ya the t.o.r.s is another thing that usually screws up on them sleds, on my other sled the tors screwed up once and it would fall flat on its face. . but then it wouldnt really go faster then a certain speed, is yours just hesitant at a certain speed?

 

[srxtriple]

I had already bypassed the tors before this happend. Anyone know how to test a CDI box? the dealers i have called tell me you cant test them.

 

[SupercaZt]

I've made some research and the only way to test a CDI-units function is to try the unit on another sled and see if the problem persits on that sled too.

The TORS can be the problem even if you've bypassed it. Check the TORS-cables to the CDI. If they are broken you don't get a closed circuit and the CDI-unit will go into TORS-mode.

 

[srxtriple]

Thanks for the input! going through the tors system and i have access to a vmax 600. if the box is the same i will test that way. All my snow is melting anyway!

 

[Undie]

the tors cuts the rpm at 3000
my gues its the stator thats broken.. im pretty sure of it...

 

[srxtriple]

What is the stator? I know of the voltage regulator, coil, and the cdi box.

 

[Bischof]

Check the resistance in your coils, plug wires and plug caps.
I had a similar problem with my sx700 a few years ago. The machine would start and idle fine but once the rpm's hit about 3000 it would bog. Turned out it was loose wire going into one of the coils.