Classic Triumph Bonneville

[Mr. Dazzle]

I posted about this bike back on the old place, but it deserves it's own thread here now.

Last year my FiL passed away and bequeathed his 3 bikes to my Wife, who doesn't ride. I kinda hope this will be the catalyst for her getting her licence, but we shall see.

One bike is a 1969 T120R. It was built in the last 6 months of bikes with a separate oil tank and is pretty much the final iteration of "classically classic" Bonnies before things changed.

My FiL bought it in '72 for the princely sum of £375 plus £7 and a half quid road tax. The receipt says (still got it, from Revitts in Ipswich) £382.5 so one of the old boys will have to tell me how you say that!

The bike's first owner bought if for racing and it wasn't road registered until my FiL bought it in '72. Before it even turned a wheel it had a bottom end rebuild, new cams, high compression pistons, clipons, rearsets, a close ratio box and lockwired everything fitted. The family story is that was all done by Rickmans but I've no idea of the reality. How much it that still remains I am not sure, but the bars and footpegs are deffo a bit racey!

It also won't do <20mph without a shit load of clutch slip, the gears are on the left and the rearsets also come with a flipped lever meaning it goes 1 up 3 down.

At various points in it's life it's been sole family transport, it's had a sidecar, topboxes and panniers etc. My wife's uncle dispatched on it in the 80s (Mids Link if anyone knows 'em).

As per my thread in the previous place it is (was) in reasonable running order. It's got a few gremlins which I've been ironing out. However last time I rode it a valve guide failed and I had to push it home, hence the red face....

[Mr. Dazzle]

So things I've done to this bike since getting it...

- Cleaned off 3 years worth of garage dust.
- Been through a small barrel of metal polish. Real chrome is a million times nicer than and silver plastic!
- Fixed a horrendous misfire caused by the ignition coil grounding wires being loose.
- Fixed another horrendous misfire caused by the aftermarket electronic ignition grounding wires being loose.
- Fixed a super wobbly Speedo caused by the cable being super loose in the back of the gauge.
- Fixed an iffy feeling brake caused by the lever pivot bolt shaking loose. Can you see a theme?
- Stripped, cleaned and rebuilt the carbs. Takes about 10 minutes! I've seen lawnmowers with more sophisticated fueling:D
- Replaced the ancient battery with a modern one intended to be used as a UPS in a fire alarm. You don't need to drive a starter motor so a dinky 9AH sealed 'deep cycling' battery for £15 is plenty.
- New spark plugs and HT leads.
- Changed the engine and gearbox oils.
- Bought some lovely new PTFE lined throttle cables to fix the rather disconcerting problem of the throttle jamming open

After all that she was riding OK and I was about to get onto tweaking the fueling when the valve guide failed.

[Mr. Dazzle]

You can actually see in the second pic the brake lever bolt is missing! With cable operated brakes it not immediately obvious though, the brakes still work.

[Mr. Dazzle]

I just looked at the receipt again because the dates didn't seem right....it does indeed say £382 1/2, not £382.50...but the UK went decimal 6 months before this receipt was written. I can only assume it was written by someone still thinking in old money

[gremlin]

I just looked at the receipt again because the dates didn't seem right....it does indeed say £382 1/2, not £382.50...but the UK went decimal 6 months before this receipt was written. I can only assume it was written by someone still thinking in old money

Don't forget, back in '72 that 50p would have bought you a 3 bedroom semi-detached house.

[Mr. Dazzle]

I just looked at the receipt again because the dates didn't seem right....it does indeed say £382 1/2, not £382.50...but the UK went decimal 6 months before this receipt was written. I can only assume it was written by someone still thinking in old money

Don't forget, back in '72 that 50p would have bought you a 3 bedroom semi-detached house.

It still would in Mrs D's Lincolnshire home town

[Mr. Dazzle]

I've given the head to these guys for investigation. When I dropped if off they had what must have been a few hundred grands worth of black and silver bikes in the workshop, she I guess they know their stuff. They also spanner for a BSB team at weekends.

https://vintageclassicmotorcycles.co.uk/



I spoke to 'em this morning. The guide hole has ovalised on the right exhaust valve, hence why it failed. The valve springs also don't match across the head - I guess there was a budget repair done at some point long ago. They're gonna speak to welding specialist to see if the hole can be built up and remachined.

Looking at new guides, valves and springs at the least. A second hand head might well be cheaper than fixing this one, but then it wouldn't be original.

[JackyJoll]

If the bike has been raced, I wouldn’t bank on any parts being “original.”

With luck, the guide hole can be trued for an oversize guide.

The photo makes it look like the valves are pocketed. That’s got to cost a bit to put right. But then it’s not the cheapest hobby.

[Mr. Dazzle]

The pocketing looks different on each side too? Might explain the different length springs?

As far as originality goes...the engine and frame numbers match. The head isn't serialized so you can't tell if it's the original, however we can tell the date is was made and it's the same age as the rest of the bike so it's a fair bet.

[Nidge]

There seems to be plenty of second hand 9 stud heads out there - and significantly cheaper than the the later T140 10 stud heads. I think I'd go down that route, frankly as long as the cases are original to the frame (matching numbers) no-one would know if the head, barrels, carbs etc etc are original

[Mr. Dazzle]

There seems to be plenty of second hand 9 stud heads out there - and significantly cheaper than the the later T140 10 stud heads. I think I'd go down that route, frankly as long as the cases are original to the frame (matching numbers) no-one would know if the head, barrels, carbs etc etc are original

I've been thinking on similar lines...

But then if I buy another head I'd probably want new bits in it anyway. Or Id want a freshly built one, which will cost correspondingly more. So what am I saving, other than the cost of the guide hole repair?

[Le_Fromage_Grande]

I just looked at the receipt again because the dates didn't seem right....it does indeed say £382 1/2, not £382.50...but the UK went decimal 6 months before this receipt was written. I can only assume it was written by someone still thinking in old money

Revitts were still thinking in old money in the 1980s, old school doesn't even begin to describe what their shop was like

[JackyJoll]

I've been thinking on similar lines...

But then if I buy another head I'd probably want new bits in it anyway. Or Id want a freshly built one, which will cost correspondingly more. So what am I saving, other than the cost of the guide hole repair?

Even if you buy a head that needs new valves, guides and springs, those are just service items.

By the way, when a Triumph head is distorted up in the middle, it’s better not to skim it.

Straighten it in a jig, or just let the bolts hold it down flat on the barrel.

[Mr. Dazzle]

I spoke to my wife's uncle (my FiL's BiL) about this today....

He seems to recall the head was switched at some point anyway after the exhaust spigot threads broke on the original. So maybe I should get a new head after all.

[Yorick]

I spoke to my wife's uncle (my FiL's BiL) about this today....

He seems to recall the head was switched at some point anyway after the exhaust spigot threads broke on the original. So maybe I should get a new head after all.

Get one with a better haircut

[Mr. Dazzle]

For some of us the lack of hair dressers in lockdown was a problem.

None of you old gits suffered of course.

[Yorick]

For some of us the lack of hair dressers in lockdown was a problem.

None of you old gits suffered of course.

Our lass cuts mine

[Horse]

For some of us the lack of hair dressers in lockdown was a problem.

None of you old gits suffered of course.

Our lass cuts mine

Filly was given an electric dog clipper. She practiced on me before doing the dog ...

[JackyJoll]

For some of us the lack of hair dressers in lockdown was a problem.

None of you old gits suffered of course.

That in the photo goes back further than March this year.

[Mr. Dazzle]

What can I say, I'm ahead of the curve.

Don't be jealous.