Honda TRX ATV Forum banner

1 - 20 of 39 Posts

·
Registered
Joined
·
25 Posts
Discussion Starter · #1 ·
Hi I have a 400ex that I completely rebuilt from the cases up. Before reassembly I checked to make sure it was shifting fine and it was so I kept rebuilding it. Well I went to put it on quad and realized that it wont shift so I tore it back down. I replaced the shift shaft and spring and wire on the shaft. The drum and forks don't show any signs of wear to my knowledge (not 100% sure what they are supposed to look like if they are worn). Anyways I have spent hours in the forums and cannot find anybody with this problem - shifts fine with cases split but wont shift when cases are back together. One thing I have noticed is that the shift stopper doesn't seem to rotate correctly on the cam it seems to bind up. Like ill be able to shift one or two gears but them the stopper arm doesn't go into the correct slot and the shift shaft fork doesn't engage with the drum. I have a new one on order but I was wondering if anybody any other ideas as to why this could be happening?
 

·
Super Moderator
Joined
·
4,179 Posts
I hate to get just a piece of the story

So you 'rebuilt' the engine:
Why?
What parts did you replace and WHY?
What parts did you reuse?
At what points during assembly did you verify transmission operation?
Do you have one transmission shaft held stationary while turning the other shaft while shifting gears?
Did you have the engine running when you discovered it would not shift more than one or two gears?

Please provide all the details of what you did and have done.
 

·
Registered
Joined
·
25 Posts
Discussion Starter · #3 ·
I hate to get just a piece of the story

So you 'rebuilt' the engine:
Why?
What parts did you replace and WHY?
What parts did you reuse?
At what points during assembly did you verify transmission operation?
Do you have one transmission shaft held stationary while turning the other shaft while shifting gears?
Did you have the engine running when you discovered it would not shift more than one or two gears?

Please provide all the details of what you did and have done.
I bought the quad from somebody when it wasn’t running. It had compression so I figured I could just replace the top end and it would run. When i was looking at it I made sure it could shift because I wouldn’t have bought it if I couldn’t have. Well when I took top end apart the piston had blown up and there was metal in bottom end so I had to take apart bottom end. Anyways I took it apart and all’s I replaced was a a few bearings that weren’t operational. One on the main shaft of the transmission and one on the counter shaft. Everything else was in good shape. I also replaced the inner clutch basket and the clutch. Along with some top end components which aren’t really relevant. At this point it wouldn’t shift so I took it back apart and replaced the spring on the shift shaft that had come unwound. And nothing changed. I replaced the shift shaft itself and I did see that it wanted to shift smoother but still won’t go through all gears. So now I ordered a new shift stopper and cam. It’s possible the forks are bent but I don’t really know what to look for. I am not really sure what you mean by having one shaft held stationary? When I turn one shaft the other shafts gears turn. Like I said it will shift when I don’t have cases together it still is a little tough to make it shift but It will go through all gears. But then when I put cases on i can get it to shift through one or two gears then it locks up and I noticed that the shift stopper arm doesn’t go into the slot on the cam on the drum it will bind up between slots. Thanks for the response.
 

·
Registered
Joined
·
25 Posts
Discussion Starter · #4 ·
I bought the quad from somebody when it wasn’t running. It had compression so I figured I could just replace the top end and it would run. When i was looking at it I made sure it could shift because I wouldn’t have bought it if I couldn’t have. Well when I took top end apart the piston had blown up and there was metal in bottom end so I had to take apart bottom end. Anyways I took it apart and all’s I replaced was a a few bearings that weren’t operational. One on the main shaft of the transmission and one on the counter shaft. Everything else was in good shape. I also replaced the inner clutch basket and the clutch. Along with some top end components which aren’t really relevant. At this point it wouldn’t shift so I took it back apart and replaced the spring on the shift shaft that had come unwound. And nothing changed. I replaced the shift shaft itself and I did see that it wanted to shift smoother but still won’t go through all gears. So now I ordered a new shift stopper and cam. It’s possible the forks are bent but I don’t really know what to look for. I am not really sure what you mean by having one shaft held stationary? When I turn one shaft the other shafts gears turn. Like I said it will shift when I don’t have cases together it still is a little tough to make it shift but It will go through all gears. But then when I put cases on i can get it to shift through one or two gears then it locks up and I noticed that the shift stopper arm doesn’t go into the slot on the cam on the drum it will bind up between slots. Thanks for the response.
My bad I actually replaced the main shaft bearing and the counter balancer bearing. Also no I never started it back up after rebuild because I realized beforehand it wouldn’t shift.
 

·
Super Moderator
Joined
·
4,179 Posts
OK - now I need to know what year model and you have and what bearing was replaced on the countershaft - there was a change in bearings between 03 and 04.
 

·
Registered
Joined
·
25 Posts
Discussion Starter · #6 ·
OK - now I need to know what year model and you have and what bearing was replaced on the countershaft - there was a change in bearings between 03 and 04.
I replaced bearing 6203 on the main shaft I did not replace anything on the countershaft. I have a 2003.
 

·
Super Moderator
Joined
·
4,179 Posts
In your second post you said:

Anyways I took it apart and all’s I replaced was a a few bearings that weren’t operational. One on the main shaft of the transmission and one on the counter shaft.
The 2003 has a 6205 NON STANDARD bearing on the sprocket end of the countershaft and I was suspicious that perhaps you replaced the 25x52x13 Honda bearing with an over the counter 6205 which measures 25x52x15 (2mm thicker than the Honda bearing).

If that is not the case, then you need to recheck the service manual and assure you have the correct shims in the correct locations and oriented as indicated. Assure you did not mix the left shift fork with the right shift fork. Leave the crank and counter balance out of the cases if necessary to assemble the transmission (only need about 3 case bolts in place for checking) and check the shifting.
 

·
Registered
Joined
·
25 Posts
Discussion Starter · #8 ·
In your second post you said:



The 2003 has a 6205 NON STANDARD bearing on the sprocket end of the countershaft and I was suspicious that perhaps you replaced the 25x52x13 Honda bearing with an over the counter 6205 which measures 25x52x15 (2mm thicker than the Honda bearing).

If that is not the case, then you need to recheck the service manual and assure you have the correct shims in the correct locations and oriented as indicated. Assure you did not mix the left shift fork with the right shift fork. Leave the crank and counter balance out of the cases if necessary to assemble the transmission (only need about 3 case bolts in place for checking) and check the shifting.
My bad I did write in the original post that I replaced the counter shaft bearing but I did not. The bearing I ordered for the main shaft was the oem bearing. I have check multiple times the shift forks are in the correct place and they are. Also I am not sure what you mean by the correct shins are you saying if I have the shift forks in the correct spot on the transmission? I guess I thought they only fit in one way. I have never seen a diagram of where they go but there is only three slots on the transmission. Am I incorrect?
 

·
Registered
Joined
·
25 Posts
Discussion Starter · #9 ·
Would it be helpful if it took some pictures of how I have it assembled and of the components conditions so you can see if there is something obvious I am missing?
 

·
Registered
Joined
·
25 Posts
Discussion Starter · #11 ·
I just took the case back off to take pictures and it shifts fine. But then I put case back on and it doesn’t shift I don’t understand?
 

·
Super Moderator
Joined
·
4,179 Posts
Are you using the paper gasket between the case halves and check the shims and orientation as per the manual (below)
4690


Having a shim (thrust washer) in the wrong place or not using the paper gasket between the halves could cause things to bind
 

·
Registered
Joined
·
25 Posts
Discussion Starter · #13 ·
I have been using a paper gasket and ultra copper. Did you see those pictures I sent it’s almost like the c3 and c4 gears on the counter shaft get caught on each other when I shift and they don’t got into the right slots. I can manually move these by hand and it shifts fine. It’s almost like when I put cases back together they bind on each other causes it not to shift which makes sense why it will shift once or twice. I’ll go through the transmission again and make sure everything is correct.
 

·
Registered
Joined
·
25 Posts
Discussion Starter · #15 ·
When it’s like that I have to manually turn it and it shifts turning the main shaft does not allow it to move. So what I am thinking could be happening is that it binds up when cases go together and then there is no fixing it and it won’t shift. Not sure what could be causing this to happen. Maybe I am missing a washer or something
 

·
Registered
Joined
·
25 Posts
Discussion Starter · #17 ·
No the transmission turns fine. It definitely is what I stated earlier that the dogs on c3 and c4gear are binding. I think the right shift fork is bent and it’s allowing that gear to drop too low causing it to get stuck. Because when I hold up on that gear slightly it shifts perfect. I think I’ll try to order a new one and hope that it fixes the problem.
 

·
Registered
Joined
·
25 Posts
Discussion Starter · #18 ·
The weird thing about the whole situation is that it shifted perfectly before I took the motor apart which is why I am confused that it won’t work now when everything is back together correct.
 

·
Super Moderator
Joined
·
4,179 Posts
I worked in a shop and was working on a Honda V65 (VF1200C) - guy brought it in because he broke 2nd gear trying to do wheelies. I had another that a guy ran out of oil. I put 3 new gears and a shift fork in the tranny along with all the incidental parts, everything worked fine on the bench, put the engine back in the bike and took it for a test ride - it seemed a bit hard to shift into 4th (which was the other side of 2nd) and I attributed it to just needing to 'wear in'.

About a month later the guy was complaining that is wasn't getting any easier to shift and it was hurting his foot pulling up on the shifter so hard. I took the engine out, tore it down and (this is the easy part) since the engine split horizontal, I was able to shift it through the gears and see what was happening. What was happening was the 2nd gear went into 2nd just fine, but when shifting into 4th the engagement dogs bottomed out against it's mating gear by about .020" - I rechecked the service manual and the parts card to assure all the right parts in the right place and then compared it to the transmission in the one that had been run out of oil - they were identical, but the old one didn't bottom the gear as hard because the shift fork had some wear.

Ultimately I determined a thrust washer was installed on the wrong side of the 4th gear that the 2/4 sliding gear had to mate to. It turned out Honda had erred and it was a model wide discrepancy. Honda issued a service bulletin and owners who complained of hard shifting got them fixed for free.

You can't really measure for a bent shift fork, but you inspect the fork for odd wear and take your best guess, but if it shifted fine before you took it apart, it should shift when it's put back together. You might have to take it to a veteran mechanic to see if he can figure out whats happening.
 

·
Registered
Joined
·
25 Posts
Discussion Starter · #20 ·
That sounds pretty much the problem I am having. I guess I’ll take apart the transmission again I don’t know how I could be putting it together wrong I’ve reassembled it about 5 times now lol.
 
1 - 20 of 39 Posts
Top