Unintended GT750B restoration

[canaletto5]

No, engine not fired up yet. I hit a disaster tonight actually. I'd fitted the chain, put the sprocket covers on, fitted the gear lever and for whatever reason decided to check that the gearchange worked OK. It doesn't. It did, I'm sure it did, but it doesn't now. It only goes into 1st. I can't change up into 2nd at all. I can't recall when I last checked all the gears, but when the engine was fully assembled on the stand It was going through all the gears OK. I'm sure of that.

I did accidentally remove the neutral detent when I drained the oil to fix a slight weep on the starter motor cover gasket the other day. I popped it back, there was no gear lever fitted at the time so the selectors shouldn't have moved at all. Should they?

It feels like the lever isn't moving far enough to change up, but it comes to a solid halt. I'm going to have to start stripping her down to find out what has gone wrong, so I am gutted. So close, now it looks like I might end up stripping the engine right back down to fix the gearchange. This is going to be one busy weekend coming up. I'll start by stripping down the clutch side I guess.

Damn.

I really wouldn't start stripping it yet Phil, Trying to change gear on a static motor is never very succesful. Try turning it on the electric start ( no fuel or plugs) whilst the clutch lever is pulled in. At the same time, see if you can run through the gears. Kev

[philshort7390]

Tried that Kev, the Motobatt spins her over at a ferocious rate with no plugs in, but still nothing doing with the gearchange.

I might try fitting the pipes and firing her up, if nothing else hearing her run will cheer me up. If I still can't get any gears with the engine running properly I don't think I'll have much choice but to start stripping her down again. Clutch side first, if I can't find anything there the cases will have to be split.

[canaletto5]

Tried that Kev, the Motobatt spins her over at a ferocious rate with no plugs in, but still nothing doing with the gearchange.

I might try fitting the pipes and firing her up, if nothing else hearing her run will cheer me up. If I still can't get any gears with the engine running properly I don't think I'll have much choice but to start stripping her down again. Clutch side first, if I can't find anything there the cases will have to be split.

Fair enough Phil but do look to the simple stuff like clutch adjustment etc before breaking it down. The neutral detent should have just picked up it's correct position as the drum rotated, that's its' job. The times I've kicked myself for overlooking the obvious because a problem has stressed me

[apwrigs]

I truly feel for you pal, you must be gutted after all that detailed rebuild. Hope it turns out ok.

[philshort7390]

Cheers guys, thanks for the encouragement.

Stripped off the clutch and I think I found the problem - the gear cam was off centre. I'd have sworn blind I'd tested the box since fitting the clutch, but perhaps not!

SO clutch all over the floor, oil everywhere, but at least it looks like I won't need to pull the engine out again. Fingers crossed. I'll reassemble the clutch tomorrow and make sure all the gears select before closing up the clutch cover.

[yeadon_m]

Phil,
I was going to suggest exactly that! I built a 550B motor, checked the gears changed OK on the bench, installed it, built the bike, only to find your issue, too! after a few hours of near heartbreak, I had the clutch over off and aha! I must have pushed the little selector / cam gear off when the cover was off and then slid it back, one tooth out. A few moments fixing it, been fine ever since
Good luck again....these things are sent to test us!
Mike

[philshort7390]

Mike

I reckon I must have knocked it when I took the clutch apart to fit the spacing shim to replace multiple washers, way back in the story. It looks OK in earlier pics where I was building the clutch up first time.

You live and learn! Off out to the garage now to put is all back together - with lots of gearchange testing!

[canaletto5]

Nice one Phil, good luck with the rest of the build.Kev

[philshort7390]

All fixed!

Here's my solution to stop the shaft moving while I tested the box and then reassembled.

Just about to fit and torque up the clutch springs:

Is it OK now? ...

[philshort7390]

Oh yes!

All that's left now is to bolt on the Delcevics and fuel her up. Much happier tonight!