Missed gears on downshift

[tony27]

My 380 seems to have a weird issue when downshifting from 3rd to 2nd, quite often it overshoots 2nd & hits neutral
All the dogs in the gearbox are good & the detents in the rails aren't rounded over so the shiftgate should be stopping in the correct place
I can't check the bike out for another 3 weeks as I dropped it off to have the suspension softened before our next meeting & won't see it again until the series sponsor gives it back to me there
Any suggestions people can come up with will give me somewhere to start after the meeting

[Bamford#69]

Hi,
take the gearbox top plate off, and have a look at the shift shaft return spring , they break off one end, usually the downshift end ,.that  spring is  pretty weak,  they usually  fail  every 35 to 40 years.
cheers

[tony27]

Haven't checked that but the lever returns to it's neutral position, will check after the meeting when I change the oil
The lever travel etc feel no different to normal & doesn't happen all the time so originally I thought it must be a technique problem but if it was why only on the 1 particular change

[Bamford#69]

Hi,
the detent springs in the side of the selector plate will make it feel that way ,
does it only  happen when you  change down? the broken spring won't return the gear lever  to the inbetween  position .
cheers

[tony27]

Yes gearlever returns so probably not spring
The only time it happens is changing from 3rd back to 2nd which is why I had a quick look at the detents in the guide rails.
While I do the oil the cover will be off so I can recheck them & the dogs, any other thoughts?

[Bamford#69]

Hi,
has this problem just started or have you changed/fixed something ?
check the spring in the shift plate,detent spring ,
Iv'e found with experience that plastic boots and the standard CZ shift lever make a lot of inadvertent/ missed shifts,
fix that by using a Yamaha gearlever and shorten the end of it  .the bit at right angle to the lever ,my CZ's are only 15 mm long ,this way you never shift gear by mistake , you have to slid your boot up or down  the case to change gear, this stopped my shift problems 

[tony27]

It's been happening on & off over the last year, I thought it was not being used to the gearchange until realising it only happens on the 1 change
Between seasons I changed most of the gearbox, originally I'd only planned on doing the bent gearchange shaft but ended up swapping pretty much everything as some of the dogs were starting to wear
I'm using a alloy lever from CZstuff which looks very yamaha like, cutting the end of the toe piece sounds like a sensible idea

[eno]

I had that problem way back in the first year of sorting out my CZ. What I found was the shift gate was overshooting past the detent. It called for a re-shape of the detent rod end and tidy up of the hole it seats in.

[tony27]

Thanks for that Eno, hadn't thought about the pin only the hole.
Steve Gallichan has my bike up at his place until the pre76 scramble & round 4 of the vmx series which means I can't check it out until then, are we likely to see you back on track soon now that you rode at summercross?

[eno]

I think I remember a longwinded investigation of the detent rod profile at cusinweedies at one time. Think about it like how a door striker plate works, you don't want the door to close too easily.
Not ready to come out & play yet, just spent the last 2 months rebuilding lawn tractor & the lifestyle/sentence main tractor. Got some firewood logs in last weekend and now have dead chainsaw. There are hundreds of reasons to not race, all of which can be overidden by the urge to do so... just haven't that urge.

[tony27]

I know what you mean about the urge, I'm feeling that way about my trials at the moment

[sudman]

Hey Tony must be them new boots

[Ian P]

You can compare to my Falta at Naki Vintage Dirt   

[tony27]

Hey Tony must be them new boots

No Tony not the new boots, had same problem last year as some rounds   

Looking forward to having a spin on the Falta Ian & seeing how you find the 400, will be interested to see how much better the suspension is after it's time with Robert Taylor 

[TM BILL]

 will be interested to see how much better the suspension is after it's time with Robert Taylor 
[/quote]

Regardless you will want it to feel better after you have been financially violated