54 Punto gear linkage broken?

I did point her towards Youtube (but not anything in particular other than 'syncromesh') and from the sound of the WhatsApp messages she sent afterwards, it seems she found something that helped. ;-)

Cheers, T i m

Reply to
T i m
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The only motorbike I had (in 1968, Francis Barnett, 175cc, 2-stroke, 3 gears, already very old at the time) had a gearbox with dog clutches. I think the gearbox was always spinning being connected directly to the crankshaft, and the clutch was a multi-plate device running in oil set between the gearbox and the chain drive to the wheel. So the gears would always engage, with a clunk as the driven gear was instantly brought up to speed.

It's a long while ago, and I can't find a reference that confirms my recollection of the drive order.

I bought it for 7 pounds 10 shillings. (Beer was 2/6 per pint, 2-stroke petrol about 6/6 per gallon.) It went like a sick pig intil I cleared all the coke out of the exhaust pipe. The magneto was useless so I converted it to battery driven coil ignition, just picking up the connection to the points. Thereafter it always started first kick.

I used it until early 1971 when I bought an old 850cc mini van. I forget what I did with it ...

Reply to
Graham J

Brit bikes had a layshaft gearbox, with main shaft running inside the output shaft. The end of the main shaft furthest away from the clutch had the layshaft drive gear on it. The output shaft was bushed to run on the main shaft, it wasn't expected that you would be in lower gears for any length of time. The main shaft had the chain driven clutch on the outer end of it. Behind that there was a "seal" (often just a felt washer and an oil flinger), then the final drive sprocket on end of output shaft. Output shaft then entered the gear box though a 2nd seal, it had 1st and 2nd gear on it, 2nd would slide on splines to mate with dogs on the layshaft drive gear for top.

So the drive train was crank, chain to clutch, gearbox main shaft, layshaft gear/direct top, output shaft, final drive sprocket.

Reply to
Peter Hill
[snip]

So the clunk was simply the rotational energy of the gearbox main shaft being transferred to the output shaft. I suspect there was some clutch drag as well ....

Reply to
Graham J

I (and quite a few BMW (and other)) bike riders also / still suffer quite a 'clunk' when we engage first gear, especially when the engine is cold.

On my old 'boxer' BM, the drive train is very much like a car ... engine, dry clutch, gearbox, drive shaft, bevel-gear, rear wheel and so there isn't (shouldn't be) as much clutch drag as with a typical wet clutch?

On some bikes that first gear selection is so loud it sounds as if the thing is going to break! ;-(

Cheers, T i m

Reply to
T i m
[...]

That actually makes gear changes worse as it has an engine speed clutch, something Beemers of the generation were always criticized for.

Chris

Reply to
Chris Whelan

But assuming the clutch is fully disengaged and you are going from neutral to 1st, why would there be a clunk at all?

Or maybe there is still some 'soft drive' going into the gearbox though background clutch drag or the input shaft bearing?

Cheers, T i m

Reply to
T i m

I should have been clearer - it's gear *changes* that are crunchy with engine speed clutches.

Chris

Reply to
Chris Whelan

Put it in gear before you start the engine.

Reply to
MrCheerful

I've an old Triumph Daytona, and the noise going into first is just awful. I had a very old Tiger Cub, and that was silent. But they were basically the same WRT clutch/gearbox layout. Very odd.

Reply to
Dan S. MacAbre

Motorcycle gearboxes seem to survive, even with the abuse. My son has ridden extensively on and off road, and at track days, and seldom uses the clutch except for stopping/starting. It makes me cringe, but nothing has broken so far.

I rallied a Mini Cooper 'S' in the 70's. It had a straight cut close ratio box, with no synchro. I used it as my everyday car a fair bit as well. The noise from the whining gears deafened me to the crunches!

It sounded much like this:

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Chris

Reply to
Chris Whelan

Ah, ok.

In this case I'd have to say the additional gear changes (1-5 rather than 0-1 etc) are ok (by comparison) and can often be done clutchless with no issue.

Could just be my boxer but they often refer to the boxes as 'agricultural' and aren't typically as slick as on my Honda etc.

Cheers, T i m

Reply to
T i m

Amazing ... but wouldn't like to be in there on a long trip up the motorway! ;-)

Wasn't it 'Bullet' (straight cut) gearboxes that were found in many sports / performance cars back in the day?

Cheers, T i m

Reply to
T i m

Yikes! What a racket. I prefer to be able to hear individual detonations, myself :-) I like a bike that sounds like a barge.

Reply to
Dan S. MacAbre
[...]

As well as the noise, it had stiffer suspension, and all the British Leyland rigid engine and gearbox mounts.

I once drove from Berkshire to Burnham-on Sea in an hour and a half. Pre speed camera days, and as close to 100mph on the motorway as I could.

I parked and went in a bar, and because of the vibration couldn't pick up a pint!

Nowadays, with a full roll cage, bucket seats, and a 5-point harness I would struggle to get in and out of it.

Chris

Reply to
Chris Whelan

I did plenty of long trips in a Mini - good, bracing fun :-)

Biggest issue used to be water getting in. The floorpan seemed to act like a scoop.

I thought the rubber suspension was pretty standard? ISTR they could supply stiffer rubber cups - to my mind that just meant solid :-)

Or was it a Hydrolastic? never had/drove one of those - apparently not as bad as they sound.

Good grief! My road trial prepared 63 Cooper never seemed that bad. Mind, I think the suspension was stock.

:-)

Reply to
RJH

Update (from Tuesday). ;-(

The main fore / aft gear change cable was broken (metal fatigue?) right next to where the Bowden cable was crimped into the main 'end'.

The 'end' was actually longer than I imagined and I believe stayed in the outer all the time (that made sense if it had to 'push' the flexible bit) and there were no obvious signs of corrosion in this case.

I drove the car back to her house after it had been repaired and it felt it all smooth and easy, hopefully suggesting it was just the cable (not a gearbox issue etc).

Thanks to all who offered thoughts and advice. ;-)

Cheers, T i m

Reply to
T i m
[...]

Originally the Mini had the rubber doughnuts. Shortly after the Austin/Morris 1100 was introduced, they fitted the 1100's Hydrolastic suspension to the Mini.

It never worked well in the Mini, giving a choppy ride; this was probably due to the shorter wheelbase. 1100's were really comfortable for the size of car, and actually very under-rated IMHO. Sadly, you could hear them rust, and many were scrapped by five years old.

Chris

Reply to
Chris Whelan

We had loads of them in the car hire fleet, I had an MG1100 with twin carbs, quite quick at the time. One of the best was an unfinished cut and shut, red at one end, white at the other, even had different plates front and back. Good car at the time, sad about the rot. My favourite was the bigger version, the Wolseley 2200 land crab, dangerously quick and loads of room inside, very comfortable.

Reply to
MrCheerful
[...]

I pulled a reconditioned engine from a rust-scrapped MG1100, stuck the

3.44:1 diff from a Mini Cooper 'S' into it, and dropped it in my (now ex) wife's Mini Traveller. It made a car that struggled to 70mph into one that was just about capable of 100mph. It took a lot of other drivers by surprise...

Chris

Reply to
Chris Whelan

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