5th gear

5th gear broke in half on my 03 wr450f while riding and locked up the back tire sending the bike into a massive skid. After taking the engine apart I found 5th gear broken in half. Has anyone heard of this? 5th gear appears to be a different type of metal than 1st,2nd,3rd and 4th. Are there any other options for gear replacement? I do not want to put the same gear back in, this is a safety issue. So can anyone offer any suggestions.


go to a machinist and have one made.

I have and have had several WR´s and all had pre-mature gear wear. I consider myself a good shifter and had no problems with previous brands. I love my Yamies but the weak point for me are the gears. When comparing the 426 to the 450 for instance you can see that the 4th gear (secondary) is much weaker designed. Yamaha must want to sell more parts. What I fiend amazing however is that there are so few reported gear problems on this forum. We must be the only ones... or not?

I've owned 4 WRs, 5th gear broke in half on my 01 and my 03... Unfortunately this is very common... I blame it on high speeds in fifth gear and weak gear material... This is why I don't think the WRs make good dualsport/streetbikes..

Not sure if the problem has been addressed yet but so far I haven't heard of any more problems with the gearboxes on the 04's and 05's... Let's hope they've addressed it....


i dont have a wr instead a yz 426. tomorrow i go to pick up the 2nd gear for my 426. the dogs were seriousally worn out and broke 2 shift forks :banghead::banghead:

I've bent shift forks,wore down the dogs etc on various dirt bikes,but never had a gear break in half.I can't imagine how that could happen. :banghead:

I broke mine when landing in 5th. Few miles before, I had a "false neutral" while shifting from 4th to 5th. Gearbox engaged the 5th under hard acceleration. Few miles after,.... disaster. It didn't shift back to 4th after several attempts. Then I got 4th and the 5th was gone. Only noises when engaged. I drove back for 20 miles, under soft acceleration. Opened the engine and the only damaged pieces were the two gears and a fork. 90 dolars of spare parts and a few days waiting. I am a soft and carefull rider, don't abbuse of my bike and never have had such problem. Can say the gear is weak. Friends that owned WRs before advised me when I was buyng this one. It's a '05 WR450F model bought brand new and is with 5,000 miles.

Another 5th gear problem here on my '02 WR 426. It was after doing some high speed stuff and I changed into 5th and it jumped straight back into 4th.

I can change into 5th but unless I'm going down a hill or decelerating (ie absolutely no load at all) it jumps back into 4th. All the other gears were fine.

Had to ride 50kms to get home with it like that.

That's the only thing that's seriously gone wrong with my bike after 10,000 +kms

Splitting the cases this week. Hope it's not going to be too expensive. All

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