False neutrals

[SophR so good]

As Ste is ignoring the problem I assume he has no idea what's causing it so suggestions of what to look at please!

1991 GPZ500 drops from 2nd into neutral whenever you shut off the throttle completely. Makes a godawful crunching sound if you then put it back into gear. Problem is exacerbated by shutting off the throttle whilst going downhill. It isn't a problem of just not putting it into gear properly before that is suggested, it will do it every time after 2 seconds or 5 minutes in gear. [/i]
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You win again, gravity! - Zap Brannigan, BCF BBQ 2016

[RhynoCZ]

Worn 2nd gear, new boots which could mean not shifting the gears properly (firmly enough)?

False neutral = you up/down shift and you hit neutral. Can happen between any gear (2-N-3, 3-N-4, 4-N-5, 5-N-6). What you have is not false neutral, as the box jumps into the actual neutral.
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'87 Honda XBR 500, '96 Kawasaki ZX7R P1, '90 Honda CB-1, '88 Kawasaki GPz550, MZ 150 ETZ
'95 Mercedes-Benz w202 C200 CGI, '98 Mercedes-Benz w210 E200 Kompressor

[SophR so good]

Once again it isn't a problem of not putting it into gear properly. I'm not a retard. Nor is ste. Obviously we have checked this.

So I got the wrong phrase. Ah well. Anything useful to say?
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You win again, gravity! - Zap Brannigan, BCF BBQ 2016

[RhynoCZ]

So, your 2nd gear is worn. Gearbox out, investigate. As simple as that.

There's not much, nothing virtually, that you could see or do from the outside.

As you checked you shift the 2nd gear properly, how's the gear shifter linkage? If it's not tight, then it would be the same as not shifting the gears properly. As the 2nd gear tends to be the most worn gear on most of all motorcycles, it's easier for the 2nd gear to slip than the other gears in the box.
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'87 Honda XBR 500, '96 Kawasaki ZX7R P1, '90 Honda CB-1, '88 Kawasaki GPz550, MZ 150 ETZ
'95 Mercedes-Benz w202 C200 CGI, '98 Mercedes-Benz w210 E200 Kompressor

[RhynoCZ]

Being 1991, the 2nd gear, you may either skip the 2nd gear when riding, rebuild the gearbox OR swap the engine. There are, or atleast used to be the last time I checked, a plenty of ER/GPZ500 engines around.

There: https://www.ebay.co.uk/sch/i.html?_odkw=GPZ+500&_osacat=0&_from=R40&_trksid=p2045573.m570.l1313.TR0.TRC0.H0.XGPZ+500+engine.TRS0&_nkw=GPZ+500+engine&_sacat=0

EDIT: I do realise, that buying a used engine is a lottery. If you want to be 100% sure, just rebuild the gearbox of your current engine.
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'87 Honda XBR 500, '96 Kawasaki ZX7R P1, '90 Honda CB-1, '88 Kawasaki GPz550, MZ 150 ETZ
'95 Mercedes-Benz w202 C200 CGI, '98 Mercedes-Benz w210 E200 Kompressor

[RhynoCZ]

OP, 3 seconds on google: https://gpz-500.com/viewtopic.php?f=17&t=870

- Jumps off the 2nd gear: ✓
- The rest of the gears work: ✓
- 1 gen. GPZ 500: ✓

[SophR so good]

If there's nothing else it can possibly be guess I'm skipping 2nd gear from now on. Clearly from the level of bike mechanical knowledge I have I am not going to be able to rebuild a gearbox.
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You win again, gravity! - Zap Brannigan, BCF BBQ 2016

[redeem ouzzer]

[RhynoCZ]

If I were you, I'd replace the engine with a newer one (avoid the 1st. gen engines, obviously). Complicated this might sound, it's pretty straight forward. Easier than rebuilding the gearbox, as for that you've got take the engine appart first to split the crank case.

If we use the Haynes ''spanner'' difficulty rating:
Engine swap would be 1/2 of a spanner
Gearbox rebuild would be full 5 spanners

IF you replace the engine, do the oil + filter and check the valve clearances.
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'87 Honda XBR 500, '96 Kawasaki ZX7R P1, '90 Honda CB-1, '88 Kawasaki GPz550, MZ 150 ETZ
'95 Mercedes-Benz w202 C200 CGI, '98 Mercedes-Benz w210 E200 Kompressor

[SophR so good]

Exhaust studs wouldn't be an issue as we had to change the whole lot already. More of a problem is that engines seem to be the same price as the entire bike. Goooddammit.

Is this something that's likely to get worse? It's only mildly dangerous right now...
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You win again, gravity! - Zap Brannigan, BCF BBQ 2016

[RhynoCZ]

Reading around, they say the worn bush lets the 2nd gear wobble. Would you like to ride such motorcycle?

Also, the engine being the same money as the bike, well welcome to very early 90's bikes owners club.

EDIT: Be glad you ride a GPZ 500 and there are a lot of spare engines laying around. Others don't have this much of luck and actually have to rebuild their gearboxes.
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'87 Honda XBR 500, '96 Kawasaki ZX7R P1, '90 Honda CB-1, '88 Kawasaki GPz550, MZ 150 ETZ
'95 Mercedes-Benz w202 C200 CGI, '98 Mercedes-Benz w210 E200 Kompressor

[Suntan Sid]

[SophR so good]

[RhynoCZ]

[SophR so good]

Please make Nobby wear a polite vest on my memorial ride.

But yeh extra careful/no 2nd gear if it's not just a loose clutch cable/tight chain/something else that won't explode until it can be fixed!
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You win again, gravity! - Zap Brannigan, BCF BBQ 2016

[stevo as b4]

If you can find a cheap low mileage GPZ in tatty condition or that has been dropped a few times, it'd be worth having the complete bike to harvest for useful spares, and also check stuff like pipe and cable routing when your putting your own bike back together.

I'd have another complete bike any day even if it gets left under a cover outside, as they'll be plenty of useful bits on it, I've learnt this alot recently and to think how I used to deride people that bought parts and spares bikes for resto's etc.

[Chris45]

Would have to agree, sounds like a failing gearbox and only a rebuild or replacement is gonna sort it. Not too sure about the wisdom of avoiding 2nd all the time, as you're mind is often taken up with all the road demands etc to remember exactly which gear your in.

Interestingly exactly this problem occurred with the CB250 N Superdream I had (last of the line, 83 model) after 18K. Nice bike, rubbish performance, it got traded.

There are plenty of second gen bikes on the market, many of which have been used lightly and they are worth every penny in my opinion.

Chris
'97 GPZ500S 33K on the clock.
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Honda CG125>Suzuki GT185>Honda CB 250N>Suzuki GSX400>Honda CX500B>Kawasaki GPZ305> Kawasaki GPZ550>Kawasaki GPZ500S+BMW 650GS

[Chris45]

[Shinigami]

I'll keep eye out for an engine then, Ive only had it do this once to me while riding it, did some testing and I could only get it to happen if I suddenly fully shut off the throttle at >5k revs I 2nd
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Current: Honda City Fly CLR125 2003 Honda CB600F Hornet 2008 Yamaha FZ6 S2 + 1991 Kawasaki GPZ500
"Once you realize what a joke everything is, being the Comedian is the only thing that makes sense.

[RhynoCZ]

[Chris45]

[RhynoCZ]

Read the thread again, Chris. It's not jumping into false neutral, it slips from the 2nd gear into the actual neutral on overrun. False neutral would be between the 2nd and 3rd, 3rd and 4th, 4th and 5th, 5th and 6th gear.

Either way, I wouldn't ride such motorcycle. Definitely not through a city, where you have to make full stop quite frequently and go over the 2nd gear.
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'87 Honda XBR 500, '96 Kawasaki ZX7R P1, '90 Honda CB-1, '88 Kawasaki GPz550, MZ 150 ETZ
'95 Mercedes-Benz w202 C200 CGI, '98 Mercedes-Benz w210 E200 Kompressor

[SophR so good]

[Chris45]

[Nobby the Bastard]

Change up or down rather than just shutting the throttle...
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trevor saxe-coburg-gotha:"Remember this simple rule - scooters are for men who like to feel the breeze on their huge, flapping cunt lips."
Sprint ST 1050