yz426 transmission. Help determining parts needed please.

5th gear off the counter shaft.

5thgearcountershaft.jpg

5th gear main shaft

5thgearmainshaft.jpg

3rd and 4th gear on the main shaft. (4th gear is on top)

3rd4th4thtopmainshaft.jpg

This is the center shift fork. I beleive it was rubbing on 5th gear.

centershiftfork.jpg

The transmission was slipping in 5th gear. At first it was a graduale slip then it would catch up. Then after a few rides it began to jerk real bad. All of this is in 5th gear only. Well as you can see, 5th gear is worn but not nearly as bad as 3rd and 4th. My question is, do you think I should go on ebay and buy a used transmission or buy individual gears OEM and replace what needs to be replaced? I would have well over $450 in OEM parts so that's not really the way I want to go. A used tranny is about 150 on ebay.

None of the gears look bad. Only the shift fork. You did not post a picture of the mating 5th gear slots, only the dogs so it is hard to know if that gear has trouble. But the dogs on 5th are a little rounded but not bad. If I were to guess, it appears like someone had a hard crash in 4th or 5th and bent the fork, thereby preventing full engagement of 5th.

The mating 5th gear slots are still good. They have a 90 degree angle with a very slight bevel. The oppsing 5th gear "wheel" they call it is about to loose some teeth though. You can see where 5th gear has been chewing at it a little. Depending on the total I'm going to get a new 5th gear, main shaft 3,4,5 and a center shift fork. If 3 and 4 are ridiculously expensive I will try to find one on eBay. 3 and 4 show the most wear and will need replaced soon anyway. If I can keep it under 300 I will be happy.

Ah.... Gave it a second look. Either my eyes are worse than I thought (probably) or your pictures are blurry at what is critical, but I see now what your concern is.

I have to wonder how they got so chewed up though. Normally, it is 1st and 2nd.

well I ended up buying a tranny of ebay. It looked perfect like it had barely been ridden. The new gears totaled $290 for a half new tranny and the used one I bought was $150. The only reason I bid with confidence is because they have a money back guarantee.

The problem you have, that of jumping out of 5th, is caused by worn lugs on the side of the third and 5th gears on the main shaft. The 5th gear on the countershaft shifts 1st and 3rd. This is a reasonably common problem. The center, #2 shift fork was bent and damaged by the force of 5th gear pushing 3rd away from it against the fork.

None of the gears look bad. Only the shift fork. You did not post a picture of the mating 5th gear slots, only the dogs so it is hard to know if that gear has trouble. But the dogs on 5th are a little rounded but not bad. If I were to guess, it appears like someone had a hard crash in 4th or 5th and bent the fork, thereby preventing full engagement of 5th.

The slots are in the picture in post 2. Obvious wear, IMO. The fork is not the cause of the problem, it was damaged BY the problem, as the 3rd pinion is forced against it hard enough to spring itself clear of 5th by bending the fork out of the way. As the fork becomes more and more permanently bent, it contributes to the whole thing by preventing 5th from fully engaging in the first place, making it even more prone to jumping out.

I see you got the trans apart good job.

Thanks. Yeah it was that one pesky bolt. Hopefully the trans I got off eBay is good. It looked to be great condition.

I tried to PM you but you don't have that option to give you a killer deal on a trans you need to open this option so other members can help you out with PM's.

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