Topic: Neutral between 5th and 6th...

[gaijin]

The last few days I've been having trouble with the 400f disengaging gears when I'm shifting from 5th to 6th. I'll pull in the clutch, shift up, let out the clutch and roll on the throttle and vrooom, it's not engaged?! At first I thought I was just being sloppy with the clutching, but something else is going on. Even once it happened after I was done shifting; running fine then slip, the RPM's shot way up into the red (I was on the highway of course) before I could throttle back and re-up-shift. Any ideas on what's causing this? I don't want to over-rev this thing any more... 

[dusterdude]

6th gear,wow that must be nice

[low-side]

Sounds like rounded dogs and/or a bent shift fork.  If your clutch is adjusted properly and you're firm with the shift pedal that's about all I can think of.

[TwoTired]

To expand upon what low-side said;  If the gear dogs aren't rounded now, they soon will be.  The shift forks can be bent, worn, or both,  Also the shifter drum groves can be worn in conjuction with the shift forks.  This can limit full engagement of the dogs and lead to their rounding as they slip out.

[gaijin]

Balls.

Well, I knew it couldn't really be anything good. Is this a typical problem of an older (more mileage) bike, or one that's had its gears crashed a lot? My 400f supposedly has only 11800 on it now, but I'm started to suspect it could be more. 

[gaijin]

Damn, and now it has trouble staying in first gear... keeps slipping into neutral, and has real tough time shifting from neutral into first.  I guess I'll have to open it up and see what the tranny looks like... 

[bryanj]

You MIGHT have a problem with the pins on the end of the selector drum and/or the detent roller mechanism both acessible after the clutch is off. Remove the clutch cover and clutch and check ASAP if it isnt that all has to com off to strip the bottom end anyway

[Gordon]

I just found this website.  Might be helpful with your situation:

http://www.salocal.com/sohc/tech/tranny/slipgear.htm

[Tim2005]

You MIGHT have a problem with the pins on the end of the selector drum and/or the detent roller mechanism both acessible after the clutch is off. Remove the clutch cover and clutch and check ASAP if it isnt that all has to com off to strip the bottom end anyway

That's good advice, there's a chance that something there has come adrift (it's kinda similar to the 750 mechanism in the link above, but on the 400 it is on the right side of the gearbox tucked up behind the clutch). For a diagram, check out page 6 of 400F parts list 1 on this site http://www.honda4fun.com/spaccati/spaccati.html

However, before you do any of this, have a quick check of the linkage that attached to the gear pedal itself (i.e. the external linkage, next to the l/h footrest), as the rose joints can come loose and reduce the amount of movement that is actually getting through to the shaft. Also check the clamp bolt is tight on the shaft while you are there. 400F gearboxes rarely give trouble, the most common problem is the countershaft top gear teeth getting stripped, but this is pretty rare too.

[HondaMan]

I remember fixing loose shifter drum pin plates on 400 and 350/4 bikes. They loved the constant shifting, but broke springs and loosened the screw that holds the round plate that holds the drum pins down. Symptoms were similar to what you're describing, so check that screw. Some of them did not get the little chink in them that kept them from working loose, or some worked loose anyway. Chink it down twice after you fix it, in any case.