The Bonneville Project

New sliders and bushes

Closer inspection has revealed one of the fork members (or sliders) has a dent in it.

This is a major blow expensive to rectify.

The dent is stopping the stanchion from sliding up and down properly.

I could bore out the dent, but there would always be a weak spot where the metal was thin.

So far as I can gather, boring out the dent would also mean that stanchion would slide unevenly compared to the other stanchion.

In short, the only way to resolve the problem satisfactorily is to replace the fork member.

I'm beginning to think I'm not really restoring this bike so much as throwing money at it - and I realise some people reading this will probably think so too.

For good measure, I'm replacing both members and the fork bushes too. Then everything on each side will be symmetrical.

The parts have been ordered from Oliver Barnes at Tri-Supply.

Details are below:

Part number	Description	Price/unit	Quantity	Total
97-4170 97-4220	Fork sliders	£132.95	Pair	£132.95
	Bushes	£14.50	Pair	£14.50
			Subtotal	£147.45
			P&P	£13.50
			VAT	£28.17
			TOTAL	£189.12

Fork member problem

I've successfully rebuilt one fork, inserting a brand new stanchion into the right-hand-side fork member.

It fitted perfectly, sliding up and down like a dream.

The left-hand-side fork member is proving troublesome.

My old Triumph workshop manual and Haynes manual say the stanchions are the most likely fork components to be bent in an accident.

But I think the left hand fork member is slightly out of true.

When fitted with the original shuttle valve from the old (slightly bent) left-hand-stanchion, the new (and straight) stanchion gets stuck half way down the fork member.

I've tried all combinations - swapping the old left-hand shuttle valve with the old right-hand shuttle valve, and the other new stanchion and each time it gets stuck in the left hand fork member.

I'm rapidly coming to the conclusion that the left-hand fork member is slightly warped.

I'm not sure what to do - I think I will post a question on the Brit Bike Forum and see if anyone has any suggestions.

Dust excluders - old v. new

At last, here are pictures showing the old and new dust excluders.

The old ones are slightly different - and in two sections.

The new ones, which are going to be fitted to the bike, are in a single section.

Even so, I'll keep the old ones as spares.

One day I might get them rechromed, although this will cost more than their replacements.

Eagle-eyed differences

The replacement stanchions have arrived from Len Craig & Sons.

In fact, they arrived two weeks ago, but I was on holiday.

Together with two dust excluder sleeves, some 40 or so ball-bearings and a couple of cork washers, I now have everything I need to rebuild the forks.

The replacement dust excluders are slightly different to the originals, seemingly with a more rounded taper.

I've probably described this badly, so I will post a photo this evening.

By the time I have done rebuilt the forks, I am hoping the wheels I ordered will have been built and returned from the Devon Rim Company.

Then I will take the frame, forks, engine and wheels to Abba Stands to be checked for alignment.

Once correct, I will dismantle everything and arrange for the frame to be painted.

Len wins another order

While the wheels are being built, I am busy sorting out the forks.

Both forks show signs of age - and one of the stanchions is bent.

I'm replacing both stanchions, both main springs, the rubber gaiters and various other bits and bobs.

I was going to keep the original dust excluder sleeve nuts, and just replace the oil seals.

But as I can buy new sleeve nuts complete with oil seals for £45 I've decided to replace them too.

I've ordered the parts from Len Craig & Sons (top left).

I purchased some stainless steel mudguards from Len last autumn and he gave me a good deal.

This time, he offered me a choice of stanchions - one pair made from Japanese steel (£40) or a pair made from British steel (£56).

I went for the British steel which is better quality.

The plan is to rebuild the forks, reattach them to the frame, slot in the wheels and engine, and then check everything is aligned correctly.

If not, any necessary tweaks can then be made to the frame before it is painted.

Once I'm happy everything is true, I'll disassemble the frame and forks, get them painted and then start rebuilding the bike proper.

New fork parts are:

Part number	Description	Price/unit	Quantity	Total
82-4047	Cork washer	2.00	Pair	£4.00
97-1891	Solo main spring	10.00	Pair	£20.00
97-3633	Dust excluder sleeve nut c/w oil seal	n/a	Pair	£45.00
97-2119	"O" ring	2.00	Pair	£4.00
97-2092	Stanchion	n/a	Pair	£56.00
97-0430	Fibre washer	unknown	Pair	unknown
97-1062	Aluminium washer	unknown	Pair	unknown
S70-3	Steel ball (1/4 in diam)	unknown	40	unknown
			Subtotal	£
			VAT	£included
			P&P	£
			TOTAL	£

I will fill in the total once I know it - it's in the region of £156 delivered.

Forks show signs of age

I dismantled the forks this morning after fettling the sleeve nut spanner so it finally fitted properly.

Taking everything apart was easy - more straightforward than I thought it would be.

One of the dust excluder sleeve nuts was tight but it eventually came loose with a bit of encouragement.

I followed the instructions in the original workshop manual. It all soon made sense after cross-referral with my old Haynes manual.

Within 30 minutes, I had both forks in bits and was holding a stanchion in each hand.

Both had seen better days.

The bottom of each stanchion, immersed in fork oil for 38 years, looked like new. But the top ends were decidedly rusty.

To check whether it was straight, I cautiously rolled the first stanchion across our glass-topped kitchen table.

It rolled perfectly.

I repeated the test with the second. It bobbled about, and is obviously bent.

Quite badly.

I'm going to replace the second stanchion. Or should I replace them as a pair?

I'm also going to replace both springs (which are slightly different lengths at rest), the oil seals (a sensible precaution) and rubber gaiters (perished).

Although the chrome on the original sleeve nuts is somewhat pitted, for now I am going to keep them because it will not be seen under the gaiters.

The worry about the bent stanchion now leads me to think that the top and bottom yokes might be bent.

But can't be sure until I get a new stanchion and put everything together again.

It's been a good day in terms of progress - I really feel I have achieved something.

But again it has turned out to be expensive.

I've posted more pictures below as an aide-memoire ready for fork reassembly.

Fork gaiter (wider lip goes towards top of fork)

Spring abutment (flat side towards top of fork)

Fork member (showing position of mudguard fixing)

Fettling the fork tool

The fork service tools I ordered have arrived safe and sound.

Neither are original - like many service tools on the market they are copies.

In fact, the fork sleeve nut spanner has an improvised handle made from a old twist grip, which made me smile.

I fought the temptation to go dismantle the forks straight straight away but promised myself I would that evening.

True to my renewed enthusiasm, I ventured out into the workshop later only to find that the sleeve nut spanner didn't fit.

Not an EXACT copy of the original tool, then.

This was really frustrating because the tool so very nearly fitted but not quite.

The centre of U-shaped mouth of the tool needed filing down so it would fit around the sleeve and allow the nuts each side to screw into their respective holes (click on the photo top left for a larger picture).

Trouble was, I didn't have a file. Plus it was late and all the shops had closed.

I managed to get hold of a file this morning and it did the job in 10 minutes.

The tool now fits and I've dismantled the forks.

Fork service tools

After much pondering, I've ordered my first two service tools.

These are non-standard tools which I apparently need to dismantle and reassemble various bits of the bike.

I say "apparently" because some people argue that you can do without them.

The first tool is a fork sleeve nut spanner (part no. 61-6017), so I can loosen the dust excluder and remove the stanchion to check it is true (see picture, top left).

The second is is a special spanner (60-0779) so I avoid butchering the fork top nuts (see picture, right).

I bought both tools from LP Williams.

In total, and including postage and packing, they cost £39.96. Expensive, perhaps, but a small price to pay to avoid damaging expensive components.

Forks

I'll get round to the forks when I can.

They look rather grubby, but fingers' crossed they are straight.

At the moment, it looks like they just need a good clean.

More updates to follow...