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Discussion Starter · #1 ·
I am trying to get an old Grizzly 450 back up and running well. It is currently stuck in 4wd. I have stripped it down and after thinking it was the servo that was broken on the front diff took that off.

Opened it up and cleaned it out then re-assembled. On plugging back in the servo operated once, when the 4wd switch was pressed but then doesn't move again. My initial excitement at it working was shortlived as it only works once. I've removed it - reset the innerds a number of times and same deal, power on press the 4wd and the servo moves....but won't move back.

It is obviously getting power but any advice on the issue would be gratefully received as I am now stuck!

Thanks in advance.

T.
 

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Clean the handlebar mounted switch. The contacts will get dirty and cause issues. Commonly known issue and easy free fix.
 

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Discussion Starter · #3 ·
Thanks for replying - I gave the switch a good check first off and all seems to be good. (Voltmeter for continuity etc)
 

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I am trying to get an old Grizzly 450 back up and running well. It is currently stuck in 4wd. I have stripped it down and after thinking it was the servo that was broken on the front diff took that off.

Opened it up and cleaned it out then re-assembled. On plugging back in the servo operated once, when the 4wd switch was pressed but then doesn't move again. My initial excitement at it working was shortlived as it only works once. I've removed it - reset the innerds a number of times and same deal, power on press the 4wd and the servo moves....but won't move back.

It is obviously getting power but any advice on the issue would be gratefully received as I am now stuck!

Thanks in advance.

T.
Sorry guys, I been out of pocket for while. Tasr12, did you get this fixed? I may have spoken to you on the phone? Let us know if you still need help.
 

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Discussion Starter · #8 ·
Sorry guys, I been out of pocket for while. Tasr12, did you get this fixed? I may have spoken to you on the phone? Let us know if you still need help.
It wasn't me on the phone I'm afraid. I'm in the military and have been away so haven't had a chance yet. That said - I'm pretty stuck so at this rate I'm reassembling with no solution.

Cheers,

T.
 

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Same here brother (Air Force), thank you for your service. You said the front servo broke off? Can you give more details? Also, are you sure it's an 02? Does it have diff lock? Parts fiche shows 400 kodiak in 02, those didn't have diff lock so a few things would be different. You cleaned and tested the switch already. The servo would be the next thing to check. Pull it off and test it with two c batteries. Make sure it turns all the way one way and back the other. If that tests good and if it does have diff lock, there are two black omron relays and a white relay that control the 4wd. You need to test those as well, next would be to give your wiring a good check over. It sounds like the bike may have sit for a while? Wiring problems are quite common, especially if it sit somewhere that mice could get to it. You can see videos on testing relays, servo, basically everything is at the link in my signature. Here it is, just scroll to the bottom and you'll see all the videos. See what you find, and let us know some more details and we can get you fixed up!

Troubleshooting ? 501 Parts.com Yamaha 4wd System Parts and Repair
 

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Discussion Starter · #11 ·
Thanks for the reply - the servo didn't 'break off', it stopped working and so I took it off the diff housing.

The quad does have diff lock - not exactly sure of the year though. Having stripped it and put it back together it then works once i.e. one direction when the switch is pushed. It doesn't move back when the switch is released. I've checked the relays under the seat - are these the right ones to check?

It was sat still and some rodents may have had access although there were probably tastier alternatives on offer!

Cheers.
 

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No problem, yes you have two black one and a white one under the seat. Those are the 4wd relays. Just to verify the contacts in the servo are good, you should test it manually and make sure it goes back and forth from 2wd to diff lock then back to 2wd. If it has set up, pull the front rack and take the plastic insert out and take a good close look at the wiring in there. Rats love that cozy little spot under the front rack. I've seen more than a few build a nest under there.
 

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Discussion Starter · #13 ·
Ok - so finally managed to get back to the bike today and spend some time. The relays are good. My diagnosis is that there should be a flat on housing the centre goes in to which the notched wheel spins. This allows the spring to gain tension when the switch is flicked. After numerous attempts the switch actuates the motor but the hole has rounded therefore there is no tension in the spring to pull it back when the switch is flicked off. Not sure if I've explained that clearly but that's what I've got. All re-assembled, choke cable replaced as it had snapped, and no in permanent 4wd for the time being until I can get a decent value replacement front diff servo.

Thanks to those who have replied.
 

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Discussion Starter · #15 ·
Same here brother (Air Force), thank you for your service. You said the front servo broke off? Can you give more details? Also, are you sure it's an 02? Does it have diff lock? Parts fiche shows 400 kodiak in 02, those didn't have diff lock so a few things would be different. You cleaned and tested the switch already. The servo would be the next thing to check. Pull it off and test it with two c batteries. Make sure it turns all the way one way and back the other. If that tests good and if it does have diff lock, there are two black omron relays and a white relay that control the 4wd. You need to test those as well, next would be to give your wiring a good check over. It sounds like the bike may have sit for a while? Wiring problems are quite common, especially if it sit somewhere that mice could get to it. You can see videos on testing relays, servo, basically everything is at the link in my signature. Here it is, just scroll to the bottom and you'll see all the videos. See what you find, and let us know some more details and we can get you fixed up!

Troubleshooting ? 501 Parts.com Yamaha 4wd System Parts and Repair
Oleblue22,

If you are 501 parts are you able to ship to an AFPO address in Europe if I was to order one of these:

Yamaha 3B4-4616A-02-00 - SERVO MOTOR COMP

Thanks,

T.
 

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We have a hard time keeping the 3B4's in stock. Got a couple of options. I have a good 3B4 but it has a chip on the edge of the plug that happened during shipping. Wouldn't hurt the function of it and you wouldn't see it when it was plugged in. That's the last one we have on the shelf right now that is rebuilt. Getting more next week. Option 2, there is one on Ebay right now for sale used $94. Not sure if the seller ships APO. We ship overseas/APO that's no problem.
 

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Discussion Starter · #17 ·
Thanks for the heads up - I will probably come back to you when I work out how to play this - for a servo and an air filter if you also do those.

Cheers.
 
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