Classic Triumph Bonneville

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Mr. Dazzle
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Re: Classic Triumph Bonneville

Post by Mr. Dazzle »

Well yes, that's the obvious solution. :D

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.
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Re: Classic Triumph Bonneville

Post by KungFooBob »

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JackyJoll
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Re: Classic Triumph Bonneville

Post by JackyJoll »

Lapping the taper in with valve grinding paste usually fixes it.

Otherwise, I’m sure it’s not a difficult job on a lathe.

If I remember right, from the last time I had gearbox trouble, the mainshaft can be pulled straight out of the cluster, towards the timing (right hand) side, once the gearbox inner cover is off. It can also be pushed straight back in, without disturbing anything.

The morse taper with right-hand threaded nut on the clutch hub is shoddy. Dave Nourish used to make splined ones for racers. I get a trouble-free primary transmission by Loctiting everything that has splines, threads or keyway.

The various tab washers don’t keep the nuts tight: they just stop the nuts falling right off after they’ve come loose. Loctite is needed.
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Re: Classic Triumph Bonneville

Post by Mr. Dazzle »

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

Post by Le_Fromage_Grande »

Mr. Dazzle wrote: Mon Aug 02, 2021 10:15 am Yeah grinding a taper I'm OK with. It's getting the shaft out of the bike and into a machine which worries me :D
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.
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Re: Classic Triumph Bonneville

Post by Mr. Dazzle »

Le_Fromage_Grande wrote: Mon Aug 02, 2021 10:44 am it was built on pre war lathes in Birmingham.
You'd never be able to guess :D
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Re: Classic Triumph Bonneville

Post by Le_Fromage_Grande »

Mr. Dazzle wrote: Mon Aug 02, 2021 10:54 am
Le_Fromage_Grande wrote: Mon Aug 02, 2021 10:44 am it was built on pre war lathes in Birmingham.
You'd never be able to guess :D
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.
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Rockburner
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Re: Classic Triumph Bonneville

Post by Rockburner »

Mr. Dazzle wrote: Mon Aug 02, 2021 8:49 am Well yes, that's the obvious solution. :D

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! :D
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Le_Fromage_Grande
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Re: Classic Triumph Bonneville

Post by Le_Fromage_Grande »

Rockburner wrote: Mon Aug 02, 2021 12:48 pm
Mr. Dazzle wrote: Mon Aug 02, 2021 8:49 am Well yes, that's the obvious solution. :D

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! :D
Run a classic bike and you'll be on first name terms with the local machine shops.
The fat cheese is hard to please
JackyJoll
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Re: Classic Triumph Bonneville

Post by JackyJoll »

Yes, Geordie my reborer died a couple of months ago.
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Re: Classic Triumph Bonneville

Post by David »

Le_Fromage_Grande wrote: Mon Aug 02, 2021 10:44 am
Mr. Dazzle wrote: Mon Aug 02, 2021 10:15 am Yeah grinding a taper I'm OK with. It's getting the shaft out of the bike and into a machine which worries me :D
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.
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Re: Classic Triumph Bonneville

Post by Mr. Dazzle »

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

Image

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?
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Re: Classic Triumph Bonneville

Post by 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
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Re: Classic Triumph Bonneville

Post by 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.

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weeksy
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Re: Classic Triumph Bonneville

Post by weeksy »

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

Post by David »

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

Post by 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.
weeksy wrote: Tue Aug 03, 2021 8:55 am 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 :D 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. :D
Last edited by Mr. Dazzle on Tue Aug 03, 2021 9:01 am, edited 2 times in total.
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Re: Classic Triumph Bonneville

Post by 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....
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Re: Classic Triumph Bonneville

Post by 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.
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Re: Classic Triumph Bonneville

Post by 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.