2nd Gear Popping out and back in

[ROOK]

Have 2005 CBR 1000.
Under heavy acceleration in 2nd gear, occasionally it will pop back into neutral. Once I back the throttle off, it will re-engage 2nd without me having to do anything.

Not a regularly thing but happens occasionally. It doesn’t happen as soon as 2nd is engaged. The gear can be selected and revs increased to near redline and then it will happen or as low as 6000rpm.

Only happens on the up shift.

Have dropped it back from third and then accelerated, on those occasions it holds fine.

Don’t believe its rider error.

Any suggestions. Have already adjusted linkages and no fix to problem there (so far)

[sathid]

My KX used to do something similar in 5th. Like someone was grabbing a handful of clutch and letting go again.

Ignored it until one day it locked solid.

Teeth missing off multiple gear sets and a selector fork busted.

$1600 in parts alone.


I'd be having a look at the gearbox before going for another ride...

[BigTim]

It sounds like worn 2nd gear, usually caused by wheelies/sloppy shifts.
Without going into too much detail, it's the sort of problem that requires the gearbox to be torn down and have certain parts replaced.
Unfortunately there's not much you can do about it now, and every time it pops out into neutral, it's causing more damage, which will in turn cause it to happen more often. Bit of a vicious circle

[Semi]

does the neutral light come on when it pops out?

[Arwon]

^^^ what Big Tim said^^^
you will most likely find 2nd and 3rd gesr worn on the dogs and worn or bent shift forks. Has to be rebuilt and will get worse.

[Captain Starfish]

Oh yeah

Happened to me twice now.

1st time I replaced the two gears for 2nd, a selector fork and shaft plus all the gaskets and crap.

2nd time I knew what it was the 2nd time it popped, so got straight onto it - this time I've got in early enough that the fork/shaft are ok, and had the gear dogs undercut for a more positive engagement.

Time will tell - but so far I've got 8000km out of it without a drama. Problem has presented itself within about 10-15000km on the last two times.

[BigTim]

Time will tell - but so far I've got 8000km out of it without a drama. Problem has presented itself within about 10-15000km on the last two times.

Just to clarify for those playing at home, this isn't normal wear.
Simon wasn't exactly gentle with his gearbox, and 'busas are putting out enough power that they will lunch gears if they're put through load that they're not designed for.

[chief wiggum]

had a similar prob with my zx9. and it will get worser and worser if ignored. spend some bucks and fix it now, or spend lots of bucks to fix it later.

[Captain Starfish]

Thanks, Timmeh

You speak the truth. I am not gentle with the busa. I do keep it well maintained, and when things like this happen I do fix them properly, sans bandaids.

It's not specific to a particular model either - most bigger bikes develop this fault, especially when they're being used to learn how to clutch up wheelies. Although by the sounds of it the older R1s were especially prone. Of course this could have been more about the type of rider that buys an R1, too...

You know how, very occasionally, you go to shift 2nd to 3rd (or vice versa) and you find that false neutral? If you fail to match revs before bashing it into gear, you get that horrible clatter and it won't go into the gear? That horrible clatter is the leading corner of the dogs grating against each other with too much differential speed to engage. That horrible clatter is the sound of those leading corners being rounded.

If this has happened to you once, and you tend to push your bike at all, chances are you will develop the whole popping 2nd problem down the track so start saving.

What's involved in the fix?

It depends. If your bike has a cassette gearbox, you don't have to drop the engine out etc. Otherwise, you'll need to:
- remove the engine
- split the crank case
- remove the gear clusters
- either split the clusters and replace 2nd gears OR take them somewhere like Road and Race to get the dogs re-ground and undercut.
- re-assemble with new fork selectors and shafts for any fork that's been ground out or bent.
- re-assemble and re-fit the engine.

My experience?
1st time, a dealer did it, without the warranty $$ for teardown (I had to pay for everything else) it cost about $1200-$1300. Most of this is labour. New gears cost about $200.

2nd time, I did most of the work myself and got the gears undercut instead of replacing them. For $100, Road and Race in Malaga took my gear clusters and rebuilt 2nd, returning the clusters ready to throw back in the bike. About $100 in seals and new bolts etc to reassemble the bike, another $100 for oil and filter.

Now that I know what I need to do, and have a list of seals etc for replacement, it would take me about a day to drop and split the motor, a day to reassemble. Allow about a week for the rebuild.

Good luck with it - and don't put this one off. Each time it bounces out, it's basically using what should be a rigid selector fork and shaft as a great big spring. They'll be fucked already, but next will be the selector drum and the seats in the engine casing which hold the selector shafts.

The longer you leave it, the worse it's going to get. It's not a cheap or easy job - but it can end up with you having to replace half your engine if you let it go...

[duffman]

+1 for dogs on second
parts arent that expensive (if you catch it early) so you can make a decent saving by doing the labor yourself

Although by the sounds of it the older R1s were especially prone. Of course this could have been more about the type of rider that buys an R1, too...

i believe in a desperate weight saving attempt Yamaha reduced the number of dogs from 5 to 3 on some of the earlier R1's. That combined with your typical R1 rider = crunch

For $100, Road and Race in Malaga took my gear clusters and rebuilt 2nd, returning the clusters ready to throw back in the bike.

were they apprehensive on doing that to an already stuffed gear?
just wondering if the fact you had caught it very early on was the only reason you had that option, or can you machine a totally rooted gearset?

[Captain Starfish]

Duffman - 2nd time around I wasn't sure about the condition. But 2nd time around I was wise to what was going around. It popped once (surprise!) when the bike was at BP, feels just like the engine misfires. I then tested it to make sure - 2nd gear, WOT and hang on. Sure enough, pop.

Busa in the garage, SRAD on the road for a week whilst I lined things up. So no chance to totally stuff the dogs.

Took the clusters into R&R together with the drum, forks, etc and asked them to take a look at it and tell me whether it was retrievable. They looked at it, no hesitation - "These will come up a treat".

Apparently, a small amount of damage on the dogs doesn't stop them from doing the undercut. And, unlike Harleys and some Euro bikes, jap gears are hardened throughout which means you don't have the drama of a deep cut going through hardfacing and exposing soft metal.

It's worth getting them to take a look and tell you - they know better than anyone whether or not it's redeemable. If it's not, and you intend on continuing to ride in a manner which caused this problem, it's worth buying the new gears and getting them undercut before you put it all back together.

[duffman]

cheers CS. exactly what i wanted to know.
If i ever have to pull a box apart again ill go for the undercut.
im fairly gentle on my bikes so hopefully it wont be for a long time, touch wood.

[Arwon]

[quote=duffman;895600

i believe in a desperate weight saving attempt Yamaha reduced the number of dogs from 5 to 3 on some of the earlier R1's. That combined with your typical R1 rider = crunch



[/quote]


Its more to do with the ratios between 1st and 2nd. On the 98-03 they are a wide ratio between 1st and 2nd then close ratio from then up to 6th. On the 04-08 they are closse ratio through the whole box.

The difference is the revs that the motor is at when you change gears and how it falls to a lower rev range in the old bikes when you hit second. Makes it a bit harder to change smooth.

The New bikes only have 3 dogs but they don't have the problems.

[ROOK]

Thanks for the advice, looks like I will spending time in my garage and replace the required parts. Wont muck around with it as its going to be my wifes bike and she wont be happy if I give her my old bike and its breaks

[duffman]

words....

interesting + informative
cheers
now i can stop going around telling people the wrong stuff

so the R1's have always had 3 dogs?

Thanks for the advice, looks like I will spending time in my garage and replace the required parts. Wont muck around with it as its going to be my wifes bike and she wont be happy if I give her my old bike and its breaks

do yourself a favour and grab a workshop manual. if you need a hand/tools then shout out.

[Captain Starfish]

^^^ amen to manual.

And read through that puppy properly, you're always going to need special tools. Half the time I took to disassemble the bus was spent making up the special little castle sockets they use for the engine mounts.

[ROOK]

Have just downloaded the manual. Figured I was going to have to fabricate special tools.
Luckily it appears I have a cassette loading gearbox, so it should only be a moderate job to pull the gearbox out and inspect/replace on the 1000RR instead of having to drop the motor and split the cases.

[Captain Starfish]

Lucky, lucky boy.

Procedure is now:
1. Undo three bolts, remove gearbox.
2. Take entire gearbox to R&R
3. Ask them to inspect and advise on replace, undercut or both.
4. Replace gearbox, tighten up three bolts.
5. ?
6. Do a wheelie.

[BigTim]

Lucky, lucky boy.

+1 Dodged a bullet there matey.

Let us know how you go

[Desmo]

What I'd give for a cassette on the R1.