My WR450 won't select 5th gear


13 replies to this topic
  • wrfthumper

Posted February 02, 2011 - 02:47 AM

#1

G'day Guys

I have a '05 WR450F and the bike will not shift into 5th gear. It runs fine in 1st to 4th but when you try to shift into 5th the lever wont move like it has no 5th gear.

Just wondering if anyone has come across this before and what you did to fix it?

  • MANIAC998

Posted February 02, 2011 - 04:36 AM

#2

It sure sounds like something is wrong inside those cases! Are you the original owner? Has it always been like this, Or did it just start acting up? Let us know a few more details and we'll try to help you out. Maniac

  • wrfthumper

Posted February 02, 2011 - 06:57 AM

#3

Thanks Maniac
No I'm not the original owner, I do know the previous owner and he said that the bike ingested water on the trail, the bike was not riden after this, all oils were drained, flushed and refilled then the problem occured on the next ride. My mate stripped the engine/trans down but could see anything out of the ordinary and seemed to shift ok on the bench, but when all together in the bike no 5th.

  • MANIAC998

Posted February 02, 2011 - 12:32 PM

#4

Interesting! Before splitting the cases again, put the bike on a bike stand and make sure it's in neutral. Fire it up, and again, make sure the wheel isn't spinning and the bike is in neutral. Then downshift into first and let out the clutch. Rear wheel should start spinning. Slowly & methodically, make a concentrated effort at shifting into the next gear and releasing the clutch. Each time, the wheel should start spinning faster & faster. If everything seems normal, and it still won't go into 5th, then it's time to get back into those cases as something is still wrong. Possibly 5th is seized onto the shaft from the swimming session. I hope this helps, and I hope I didn't come across as offending you, but I have no idea how experienced you are as a rider or as a mechanic. All I have to go on is that your new on ThumperTalk, what with two posts to your credit. Hope this helps, and you can give us some more information so we can get this bike running again for you!:thumbsup:
Maniac

  • 74dirtdown

Posted February 02, 2011 - 05:42 PM

#5

I wonder if mine is also broken. That would be a gear this rider has not yet experienced.

  • wrfthumper

Posted February 02, 2011 - 07:29 PM

#6

No not at all Maniac, I really appreciate your help. Just a little of my back ground, I have been a motor mechanic for 14 years mainly working on cars and trucks, I have only ever rebuilt one bike that was my 96 CR250 about 10 years ago and thats the only bike experience I have but hey I am a mechanic and the bike is a machine so I should be ok, it's just good to get a bit of info before you start :-)

Anyway back to the bike, I have tried what you suggested and was very deliberate with the gear changes and it selected all gears fine with the back wheel off the ground. I decieded to take it for another ride and now it will select 5th but has no drive so I'm thinking it may be a similar problem that other forum members have faced. possible bent selector fork and/or damage to 5th gear dog teeth??
Im going on holidays in 2 weeks so wont get a chance to tear down the transmission, but will do on my return, will let you guys know what I find.

  • MANIAC998

Posted February 05, 2011 - 05:17 PM

#7

I've been looking in the manual, and nothing seems to jump out to me on where to start looking. Have you done an oil change, and if so, did you notice alot of shavings or metal? And you say one of your mates has already tore it down once, without finding anything? Very unusual! Did you check the Shift drum or Shift cam some like to call it? Let us know what you find. Good Luck. Maniac

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  • foxomatica

Posted February 05, 2011 - 09:27 PM

#8

I had a similar issue with my 94 CR 250 and it was the shift drum. A small bit of the casting had broken off where the fork rides therefor not allowing fifth. It was a relatively straight forward job (following the manual) to spit the cases and replace the drum though it was a 2-stroke which made putting the top end back together a snap. Defiantly more work with the WR!

  • wrfthumper

Posted June 13, 2011 - 03:53 AM

#9

Well I have finally found the time to tear down the motor/gearbox and closely inspected everything to find that the shift fork number to had a bit of wear causing the 3rd gear pinion and 5th gear pinion to have very poor mesh, as a result there is a bit of damage to the dog teeth. have ordered the parts and just have to wait for them to arrive from O/S.
Will post when it's all back together and let you guys know how it went.

  • MANIAC998

Posted June 14, 2011 - 06:44 PM

#10

Good luck! And definately let us know how it went! Maniac

  • wrfthumper

Posted June 30, 2011 - 07:08 PM

#11

Ok guys, the bike is all back together and working great, no more dramas with 5th gear :thumbsup:
I've added so pictures so everyone can see what went wrong with my bike and hopefully help others in diagnosing their bike.

Posted Image
This is the 3rd gear pinion, as you can see there is damage to the dog teeth and bits chipped out of the teeth.

Posted Image
This is the 5th gear pinion, you can see where the dog teeth from the 3rd gear pinion have been rubbing on it causing it to wear down about 1/2 to 1 mm

Posted Image
This is number 2 selector fork, I believe this is the cause of all the drama, you can see the wear marks on it.

  • MANIAC998

Posted July 01, 2011 - 04:01 AM

#12

Now that's how a "newbie" is supposed to act here on ThumperTalk! Thanks for the excellent write-up wrfthumper! Glad to see you got her back together and working well. Now go out and beat on her some more!!! And welcome to ThumperTalk!!! Maniac

  • zlathim

Posted July 01, 2011 - 05:27 AM

#13

Thanks for the follow up wrfthumper. This thread will serve others with the same problem well.

I'm a member of a lot of different forums (mainly automotive), and it is frustrating to find a thread in which the OP is having the exact same issue as you are, but they never came back to tell how they fixed it. Kudos on a diligent diagnosis, repair, and documentation.

  • mrBird

Posted July 03, 2011 - 12:01 PM

#14

I asked some questions about this in another thread. In the end, I was a bit paranoid about this, so I teared it down instead of just stop using 5th gear.

I have the same problem. A bent shift fork looking exactly as on the pictures in this thread. Gonna order a new one. Was thinking of replacing the gears for 3rd and 5th as well, but they were quite pricy (at least here in Sweden). How much of wear could I tolerate without needing to replace them?

My 5th gear looks like this:
Posted Image
This gear isn't really (in my opinion) in to bad shape, and should be usable. Or what do you think?

My 3rd gear looks like this:
Posted Image
What do you think? Is there to much wear on this gear to reuse it? I'm thinking about getting either a friend or some local shop to use a grinder and fix this gear if it is possible. Here in Sweden, this is a $250 part:foul:. I don't want to buy that one unless it is necesary. But I dont want to split the engine again either...:thumbsup:




 
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