Razor mx350 dirt rocket-blue light won't cut on or start

Razor E300 chain adjustment fix

Loosen both rear axle nuts, pull wheel back but keep it straight in the frame. retighten bolts

There are a few wiring diagrams here for MX350, should be one that matches your version.
http://manuals.monsterscooterparts.com/recreational/Razor/Wiring/

MX350 is a 24V bike.
You could change the gearing by replacing the sprockets, or you could replace the electric controller and upgrade to 36V, but you probably would be better off getting a bigger model, like the MX500, as this uses 36V already and the higher voltage allows for higher motor rpm.

the user manual for the Razor MX350 is available on the web.
here
http://manuals.monsterscooterparts.com/recreational/Razor/
it shows how to remove/install the rear wheel.

user manual is here http://www.electricscooterparts.com/manuals/razor-mx350-mx400-manual.pdf

The guide for battery replacement is here http://ep.yimg.com/ty/cdn/razorama/mx350v19battery.pdf

other useful information and guides
http://www.razorama.com/razor-installation-guides.html

Owners manual http://www.razorama.com/razor-owners-manuals.html

Have a read of the trouble shooting guide here,
http://www.razorama.com/razor-installation-guides.html

It sounds like a fault with the charger. Test the charger output with a voltmeter to confirm correct operation. IF OK then check the wiring , fuse, switch conections between the charger and the battery.
wiring diagram is here http://manuals.monsterscooterparts.com/recreational/Razor/Wiring/

wiring diagrams can be found here

http://manuals.monsterscooterparts.com/recreational/Razor/Wiring/

is this what your looking for by any chance ?

http://dirtrocketmx350.com/razor-dirt-rocket-mx350-specs/