trans problems!!!

[Zeb400EX]

Ok so, this winter I finally made my 03 ex a 416 and kinda did a whole rebuilt shock,swingarm, new clutch, bearings etc. Got it back together a couple of months ago it ran great. Big power increase! First ride after the rebuilt blew 2nd gear out.

K,well I had a spare bottom end. Stole 1st,2nd, and 3rd gears on the main shaft from the spare bottom end. Got that all back together everything ran great. When to HM trails in West Virginia. Rode like a 100mi or so. Blew out the axle bearings last day in WV. Got home replaced bearings. Rode again here on my trails and blew 2nd gear out again!!!

I'm getting ready to tear it all back apart this weekend,but I don't really know what to look for in the tranny. I mean should I just start by buying all new gears and shift forks or what? I know there's gotta be a reason why I'm going through 2nd gears. You guys think maybe its because I used the used gears or somthing else? Has anyone had this much trouble out of their aged trannys after add more power? All I added was the 11:1 piston and that shouldn't be enough to start blowing gears out!

Any suggestions??

[tri5ron]

maybe Trans shaft bearings ?

[Zeb400EX]

So your thinking the bearings could b wore out enough to cause the shafts to have a little play?

Both times it blew, it started to rip out of 2nd under full power. Then it got so bad that I could click into 2nd and give it about 1/4 throttle and it would just start grinding.

[400exshop]

take a look at the shift drum and shift forks. mite not be going in the gear all the way....

[Zeb400EX]

Well I tore my motor apart and figure out what went wrong. All the gears looked great, but the the dogs that go into the 2nd gear on the counter shaft were dulled pretty bad. Also inside the 2nd gear were the dogs inter lock into the gear were almost notch out from where the dogs were poping out under load. Guess with the addition of the more power of the piston and my wore out 03 tranny wasn't a good mix

So my option is to buy a used gears on ebay and risk it happening again, or buy new. If I replace it with new its really expensive. Replacing just the 2nd and the gear that locks in and replacing the 1st gear and the its interlocking gear is like $280. The 1st gear is wore bad too. Thought I should go ahead and replace since I'm already there.

What should I do? The gears sets on ebay look great in the pic,but I can't really see the spots where my is wore out. So they too could be in the same shape. O I also found a whole bottom end here locally for $150.