alright here's the deal. I bought i 2004 kodiak for a great price but i has some issues that i need help with.

the first is the atv shows a random MPH while setting still and it changes when you start moving but is by no mean accurate. shows something like 5 MPH sitting still and like up to 25 MPH while moving in low range.

the second is the atv shutters in reverse and won't back up. it idles fine in reverse but when you give it throttle it shutters like it would if you were backing up too fast and the speedo shows somewhere around 10 MPH but i'm not moving.

could both these issues be related to a speed sensor somewhere? any help is greatly appreciated.

 

Not that familiar with the 450's but these Grizzly Riders - Yamaha Grizzly ATV Forum guys are.

 

Have you checked your lights when this is happening? are they on steady or flickering? A ground could cause the same problem. I had this happen due to a loose connection once and just touching the wires would make it happen so I traced it out and found a bare section of a wire resting up against the frame. Their is a speed sensor also located on the left side just above the plastics that cover your oil fill/check. It can also happen due to the overide button or servo switch in the front diff going bad. Start at your fuse box and make sure all your fuses are good and work your way towards the front of the 450 checking the wires for loose connections all the way to the display.

 

all dash and headlight work and are steady, not flickering or blinking

 

Then it will be the speed sensor or the servo switch I would think. What you are describing is almost like you are in diff lock and the bike is bogging down when giving too much throttle and the limiter is kicking in. Did this just start happening all of a sudden or was it after running through water or mud?

 

i was like this when i got it, they said it started doing this about a week ago..

 

Still think it was due to water or mud so I would start checking all the wires and connections from the fuse box to the display. Chances are something is grounding out due to water or a bad connector. If all that checks fine you could need a new speed sensor. The display could be going bad also but highly doubtful. Unfortunately the problem sounds like it is electrical and without starting to rule things out you'll never know what the problem is.