gear selcetion problem

[3potjohn]

I've been rebuilding my 350.Yesterday I was intending to get the crankcases together.However I have run into a problem with the gear selector mechanism. I had this apart 8 years ago but did not encounter any problems with the gearbox on rebuild. This time it will select up and down all 6 gears and neutral but when i tighten the cases the gear selector binds and I cannot get the gears to select. I have had the cases apart and back together several times.This in itself worrisom as it risks introducing muck into my clean cases.Not to mention damaging oil seals.
Should the gear change shaft have a washer/shim at each end? Unfortunately when separating the cases the gears came loose so i may have mislocated a shim.It looks right according to the diagrams.
I have tried with and without the washers on the gear change shaft but as soon as i button up the cases it binds. I reheated the cases and tapped the shafts in and out lightly in a bid to reseat somthing but to no avaiI have looked hard at the cluster and believe it is all assembled correctly. I've read and re-read both the blue book and the harglo manual.
Any bright ideas?

[George 350]

Hi John,
Did it originally have a gasket between the crank case halves? Both my bikes are 1978 registered and each originally had a gasket but have no idea when this was deleted in production. If so, and you are now building with just a sealant, then you will need to check that you haven't got too many shims on each shaft.

If it isn't as simple as that, then as I see it, you will need to assemble the cases with just one gear shaft in at a time, the selector drum in on its own, and finally the selector shaft to try and determine which of the shafts is causing the binding.

Good luck,
George.

[3potjohn]

No gasket,never had one.I don't usually get stumped with gearboxes,as have a couple of fat Beemers and they seem to fail after only about 30-40k.It's easy to be wise after the event but I wished i hadn't fitted the oil seals. I'll try and ease them out so I can play with the shims and case. Unfortunately this spell of quite weather is about to end,which means i don't want to empty the garage.There's not room to swing a cat normally.

[3potjohn]

I'll add that i did not disturb the stopper plate.

[mad muller]

have you got the return spring on the selector shaft fitted right it needs to be under tension, if its not located right it can give the symptoms you describe worth a look.

[3potjohn]

I now have selectable gears on my 350, with the cases bolted together. This has been achieved by placing 2 washers one at each end of the gear shift spindle and removing the one washer from the left hand side of the selector drum shaft. However to my mind it ought to have one on this end as it runs directly in the hole in the left hand crank case. I rather think there is a witness mark but it doen't seem to appear on the diagrams I have.

Can anyone confirm that there should or should not be a washer on this left hand end? I fully realise all this shimming is likely to help or hinder good selection. I don't want to get the motor running only to discover I need to rip it open again.

Moral of story,don't open the crankcase and let all the innards fall out.
It wouldn't be me if it went entirely smoothly of course as I contrived to step into the tray of case bolts sending them all over the nether regions of the garage.We'll meet again etc etc.......

[72degrees]

There isn't a shim in that position on the selector drum shaft on mine but it has gone back together with one each end of the gear shift spindle as you describe. So do you now have one shim 'left over'?

I have to confess I'm still slightly apprehensive about the gear selection on mine though, so don't take my word for it - well at least until I get it running again sometime later this week - hopefully.

[SupermotoDave]

It probably won't help, but if you go onto the Bike magazine website this month, or follow this link
https://www.youtube.com/watch?v=c6WR1VQu6Nk

you can see a 30 second film on how to assemble a Morini Camel bottom end featuring Hugo Wilson and Benjy Straw.

David

[3potjohn]

Hmmmmm, and i thought Andy Partridge's history of rock and roll in 22 seconds was fast. Could have been very useful.
Is that a Triumph Stag in the background?

[SupermotoDave]

You can slow it down to 0.25 speed on youtube if that helps.

My opinion is that they are Cromodora CD1 or CD3 which makes it a Fiat 124 spider or more likely a Fiat Dino looking at the length of the bumper return.

[3potjohn]

After a bit of intensive work i have just the pistons and top ends to fit.Except a nagging doubt...did i fit the spacer facing on the gearbox mainshaft with the chamfer in as i beleive,or facing out.Only one way to check I guess.......

[3potjohn]

After a bit of time off this afternoon......the bike is back together. I had a lot of trouble with old and cold petrol pipes and carb rubbers.Cut some new tubing off the roll I had. Carefully unwrapped the petrol tank to refit and chipped the paint on the headstock.Nevermind.This is damned exciting.Would not start so pushed up the hill and after a bump away it went.Carbs all over the place, probably the cables are nipped up under the tank and kickstart to reposition as the ratchet was just audible. Oh happy day.