no reverse ,no light blinking,no beep

[apexxtx]

2008 ,started last year sometimes would work, keep getting worse, now nothing, push rev button nothing, no beep, no light blinking
checked all electrical, all good
if I run jumpers to servo and put it in reverse ,then start up unpluged, then plug in works fine, till shut down, then nothing
there is 2 swicthes on gear case,how do they work

 

[apexxtx]

anyone

 

[yamahas]

I don't think the problem is in the gear case/reverse mechanism.

Have you checked fuses and relays?

 

[apexxtx]

fuses and relays all ok,if you start sled with servo unpluged then plug in works fine,till you shut down,then start again,then nothing

 

[Mooseman]

The two switches on the servo tell the PCM that the requested gear has engaged and allow the engine to rev higher. If it doesn't get the signal that the gear is engaged, it won't allow the engine to rev too high to prevent damage to the gears by a sudden engagement of the gear. the light will blink and you will get the weird off-beeping.

This thread went through the same issue:
http://www.ty4stroke.com/viewtopic.php? ... highlight=

 

[apexxtx]

thats just it,no light, no beep,nothing

 

[SnofishersBuddy]

Have never experienced that problem but it sounds similar to a bad servo on an atv.

Testing the two gear relays is just a continuity check.

The servo check is a little more difficult as you may here it spin when power goes to it but it may spin the wrong way. It requires getting a look at the pinion on the end of it while you are activating it.

If you have access to a service manual it helps out a bunch with testing both.

 

[apexxtx]

servo works fne

 

[Mooseman]

Is the fan running when you try to shift it?

 

[apexxtx]

no fan running,what would be the concection

 

[yamahas]

In the link Mooseman posted there was the idea brought up the when the fan is running it draws too much power for the reverse to engage.

If the relays/ruses/servo all checks out I would look into the button itself possibly.

 

[apexxtx]

check button,all works,the strange thing is ,turn sled off,disconnect servo plug ,jump it to reverse,start sled,plug in servo all works normal,turn sled off,then start,no reverse

 

[yamahas]

So when you do that you can ride around and use reverse and forward like normal until you shut down the sled?

 

[apexxtx]

thats right

 

[Mooseman]

I have seen mine do the same thing when the fan was running, as well as cutting power to the hand warmers. The thinking being that the PCM won't allow the servo to work due to the high current draw of the fan.

But you've said that it does shift when you unplug and plug the servo. I'm thinking that your servo has bad contacts or is defective but at $220, that's an expensive guess. There are contacts inside the servo that tells it where it is in the shift pattern. You would need to open it up and see how the contact fingers are. Maybe clean up the contacts and put some new dielectric grease on them. I opened mine up and it's not that complicated. You sort of see how it works when it's open. You can even pop out the tiny motor and test it on a 12V supply.

Edit: Man I'm slow. While I was writing this out, you and Yamahas have been having a conversation! Still, I would look into the servo itself.