Classic Triumph Bonneville

[Le_Fromage_Grande]

it was built on pre war lathes in Birmingham.

You'd never be able to guess

I used to work in a lawnmower factory in the mid 80s, I was using lathes and grinders from the 1930s on a daily basis, the only special tools we had were ones we'd made ourselves. In 1987 we got a CNC lathe, it was like the space age to us - it also did a better job that any of us.

[Rockburner]

Well yes, that's the obvious solution.

The head was repaired and the cylinders we're re-honed by this guy, he's just down the road from me. His shop has about a dozen lovely looking 'black and silver' bikes whenever I go there and he spanners for a BSB team, so I assume he knows what he's doing. He did a lovely job on the head.

https://vintageclassicmotorcycles.co.uk

I'm under no illusions that it can be fixed, it's just a question of how difficult/expensive it'll be.

Ah good - another recommendation for classic bike work should I need it... bookmarked thanks!

[Le_Fromage_Grande]

Well yes, that's the obvious solution.

The head was repaired and the cylinders we're re-honed by this guy, he's just down the road from me. His shop has about a dozen lovely looking 'black and silver' bikes whenever I go there and he spanners for a BSB team, so I assume he knows what he's doing. He did a lovely job on the head.

https://vintageclassicmotorcycles.co.uk

I'm under no illusions that it can be fixed, it's just a question of how difficult/expensive it'll be.

Ah good - another recommendation for classic bike work should I need it... bookmarked thanks!

Run a classic bike and you'll be on first name terms with the local machine shops.

[JackyJoll]

Yes, Geordie my reborer died a couple of months ago.

[David]

Yeah grinding a taper I'm OK with. It's getting the shaft out of the bike and into a machine which worries me

Lapping the taper in should do it, you don't need to remove the shaft to do this.
If you need to get the gear shaft out it won't be difficult, just time consuming, it's a Triumph, it was built on pre war lathes in Birmingham.

Meriden, Shirley.

[Mr. Dazzle]

Taper and woodruff are both OK by the looks of it. Gonna relap anyway since I'm here.



The nut which clamps it up (goes on the thread you can see) was pretty loose though. Should be done up to about 70lb.ft (IIRC) but it was barely more than hand tight. I suspect that was the problem as JJ said.

The female side of the taper has some rust on it. Theoretically this taper is sealed up by virtue of being a tight fit, so how can water get in there to rust?

[Le_Fromage_Grande]

Lap it in anyway, it's not going to hurt.

Night just be the photo but the thread looks a bit ropey

[Mr. Dazzle]

Unfortunately I thibk something else is still broken.

These two bits wobble and turn relative to each other loads. They shouldn't, AFAIK. The centre peice should slide out fairly easily, but it ain't. Apparently force is now required to get them apart.

Could well be that the rubber blocks inside have shat their pants. Who knows until I get it apart.

[weeksy]

Good luck mate... even though i don't really 'do' engines, it's still interesting to watch.

[David]

They shouldn't wobble much..but if they don't turn relative to each other it isnt a clutch.

[Mr. Dazzle]

Yeah sorry, badly phrased - they have loads of rotational 'slack' where you can tell there probably should't be any. Things feel loose.

Good luck mate... even though i don't really 'do' engines, it's still interesting to watch.

'tis funny, my day-to-day work is right up the other end of the scale from this stuff I do do engines, but everything I've dealt with for the last 10-15 years has been brand new tech. Right now I work in the "New Technologies" division of an Automotive OEM.

This Triumph is so different to what I usually work with I'm often left thinking "is it really just a case of pulling them apart?!" etc.

[David]

And..as Weeksy said...good luck!
I haven't looked at one of these for a while and i am on yhe2 loo right now...when i finished my ablutions and am pretty enough to. face my Public I can have a look at my beezer manual...it works the same way....

[JackyJoll]

It’s quite normal for the shock absorber (the bit with three studs there) to be tight on the splines of the small hub.

There is always a bit of wobble between the shock absorber and the chain wheel/drum. When assembled, that means the drum wobbles a bit when you pull the clutch lever. The wobble disappears when you let the lever go, because the springs and plates squeeze the shock absorber and the drum together.

There’s a sort of big thrust washer between the hub and the back of the drum. It wears and causes more wobble.

There are twenty small rollers that fall out when you get the hub/shock absorber splines pushed apart.

[JackyJoll]

If the shock absorber rubbers have crumbled away, you may be able to feel rotational play between the splines inside the shock absorber and the body of the shock absorber. It’s easier to detect while it’s still mounted to the gearbox shaft and in gear.

A little bit of rotational movement against the springy rubbers is normal, but it should not be much movement and should require quite a lot of force.

[Mr. Dazzle]

If feels like the rubbers are shot, but who knows. Someone else on the old boys forum pointed out that there's a lot of black gunk in there which could be rubber debris, but it could also be friction material.

If I do need new rubbers I'm tempted to just buy a new hub.

[JackyJoll]

For future reference:

[JackyJoll]

If feels like the rubbers are shot, but who knows. Someone else on the old boys forum pointed out that there's a lot of black gunk in there which could be rubber debris, but it could also be friction material.

If I do need new rubbers I'm tempted to just buy a new hub.

Yes I bought a new complete shock absorber and it’s lasted a long time.

[Nidge]

Have you come across the Lunmad YouTube channel yet? This episode might be useful

[Mr. Dazzle]

For future reference:

The thing is, even if it's previous broken state it certainly felt fast. Even by today's standards it's by no means slow. Obviously it's not a patch on a big modern bike, but she'll outrun alot of stuff on the road. It must have felt like a rocket in 1969.

[Lutin]

I've a copy of an article from Classic Bike on how to Overhaul a British Clutch. The article uses a 1969 Triumph 650 TR6P three spring clutch as an example. I cannot post it up as it's too big (and a breach of copyright). Pop me a PM if you're interested.