99' yz400f HELP!! trannnyy problems.

Just to make it clear ive already tried searching and read over 2 pages of posts and nothing has given me an answer.

Last August I took a nasty spill, ended up tearing my mcl so I was out of riding for quite a while. My bikes throttle got pinned while the bike was on its side, The crank didn't like freerevving like that, and well, the big end rod bearing locked up.

SO, I'm working on putting the new crank and piston in and getting it runnin again for this spring. I checked the tranny to make sure it shifted thru all the gears properly right after I got the cases together, everything was butter, shifted perfectly. I checked it again after I put the shift shaft in and the external shifting machanism, again it shifted perfectly. I assembled the rest of the motor and mounted it in the frame, hooked up all the lines, put the carb on, exhaust, almost ready to go.... I tried shifting it, when I put it together I had it in first gear, it wuold not shift out of first gear. The shifter wasn't locked up or anything, it would still move up and down about 3/4" but it was like metal on metal, and it wouldn't come out of first, not even go into nuetral.

:ride: :ride:

So I was hoping that while I was putting the right side cover on I must have gotten something on the external shifting mechanism out of place, took it apart, everything was perfect, I took it off anyways to see if I could shift the tranny by just turning the shift drum, >NO GO< it will turn about 1/16th of a turn, then its just a solid metal on metal sound :applause::naughty::busted::ride:

so I thought just maybe something might be binding up because the only lube that was in the tranny was just a light coat of motor oil that I put on during assembly. So i put the clutch cover and everything back on and filled it up with oil, well needless to say that made no difference at all.

What could this possibly be? My guess is one of the shift forks is tweaked.

When I took the bottom end apart i never had the gears off the main or countershaft, I put zipties on the ends of the shafts so the gears wouldn't come off, just so I had less parts to get mixed up. I quadruple checked before I put the cases together that the shift forks were in there proper places, and I used a cylmer manual to do all this, so it was the correct way.

Could a shift fork possibly tweak so that if the gears were in the perfect position it should shift fine but as soon as it got moved around it wouldn't?

I am honestly stumped and this isn't the first crank rebuild I've done on a bike, granted it is the first 4 stroke bike, but its really no different in the bottom end. I've done a crank on my blaster and my old cr80 and I never had a problem like this.

How do you check if the shift forks aren't perfectly in spec?

Should I just take it all back apart and replace all the shift forks?

This just isn't making sense to me.

one more thing I noticed. are the shift forks pressed onto there shafts? Because I noticed that my Right shift fork, there was a TINY bit of play between the aluminum fork and its shaft, hardly noticable, but all the others were 100% tight, is this a problem?


Oh come on!! I have a serious problem here! please help me. What does this sound like symptoms of!?

try rotating the counter shaft sprocket at the same time you are trying to shift. Kind of like when you kill it and it wants to stay in gear and you want neutral so you can start it. Rock it back and forth as you try to shift it to see if it will shift out of gear.

Not sure if this helps or not, but these trannies are designed to be shifted with things spinning and not at a stand still.

Just a thought.

As for shift forks bent, this will usually not happen to a tranny if the forks are bent, you usually will beable to get the bike into a gear, just once power is applied it will not stay.

Let me know if I sent you the wrong way.

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