2000 GPZ500S can't select 1st gear

[CaptainCrash1...]

Hi, folks, new on here, so HELLO
Anyway, just bought a cheap GPZ500S to have a tinker with over the winter after been away from bikes for 18 years.
It runs lovely, although not ridden it yet as it has no MOT.
The problem I have is it won't select 1st gear. I've tried tightening the clutch cable, but that makes things worse. Pressing down on the selector just feels like it's already in first with nowhere else to go, no clicking or nothing. It will click up into 2nd and will drive the rear wheel, and will go up through all other gears. It is a bit vague through the gears though, certainly wouldn't want to ride it like that.
I'm going to take it apart on Friday, but any simple ideas that might solve it are greatly appreciated. I have read somewhere I might need to back the clutch off rather than tightening it, but there's no play left on cable, and clutch actually works fine.

[doggone]

Sometimes it can just be the shaft from the pedal into the box - where it goes through the case needs a spot of lube regularly.

[stinkwheel]

Presumably this is with the engine running? Because it has a neutral-finder so it will be very reluctant to go into gear with the engine and bike stationary, one of the two needs to be moving.

There is a primary gear selector mechanism under a seperate cover located behind the front sprocket (it won't look like it until you remove the sprocket cover, the sprocket, the metal guard and clean all the crap off it.

It's effectively two hooks that grab a notch on the selector drum and rotate it one position round one way or the other when you change gear. Over time the points on the hook can wear rounded and slip off the drum instead of moving it.

It is an epic fiddle but you CAN get the whole lot out and back in again with the engine in the frame. I've done it twice. The entire splined shaft comes out, it's about 3" long with the mechanism attached. Relatively simple to file a point back on the selector notches and that's it fixed for another few tens of thousands of miles.

Be warned, my description is quite simplistic, there's a lot of small springy things in there, take digital photos as you dismantle it!

There are a few on ebay too for not very much money. It might be simpler to take the old one out and throw a replacement in rather than messing about with little pingy springs.

If you lean the bike over to the right a bit (steering over to full lock and lean the bar end against a wall), you can do it without draining the oil. This also makes it much easier to see what you're doing,

Could also be an issue with the gearbox itself but I've had one failing to engage gears twice now and both times it was that.

You may want to consider fitting a new shaft oil seal while you're in there. You will need to make or buy a new paper gasket for the cover.

https://www.ebay.co.uk/itm/Kawasaki-GPZ500S-Gear-Selector-Shaft-Mechinism-Changer-EX-500/133011637139?hash=item1ef81c8393:g:iK0AAOSwXY5ZQCn-
____________________
“Rule one: Always stick around for one more drink. That's when things happen. That's when you find out everything you want to know.”
I did the 2010 Round Britain Rally on my 350 Bullet. 89 landmarks, 3 months, 9,500 miles.

[CaptainCrash1...]

Cheers Stinkwheel
I'd read about the gear selector, but struggled to visualise it. Now I know it's just behind that panel I'll have a proper look kn Friday. Especially if I can do it without draining the oil. I'll let you know how I get on.

[CaptainCrash1...]

Had a look today, and thought it was something worse as I couldn't rotate the selector drum into first by hand, but could select second.
I removed the pawl (the bit with the selector teeth) and flipped it around so the up tooth was now the down tooth and visa versa.
When I re-installed it all I can now only select first and no other gears.
Result
I've ordered a new pawl (£4.50) and gasket (£4.50) and so that should be it.
I did it as you said, but I guess I didn't have it tipped far enough over , as I spilled about a pint of oil, but no harm no fowl, managed to catch it in a container. It needs a service, so oil and filter getting binned soon anyway.
The only negative is that the little metal ring on the selector drum is a bit damaged, so the neutral light stays on when in second gear, going to have to find a solution to that.