Grant's Featherbed Special

On the timing side, I decided to ditch the distributor and coil, and went up the modern BT-H magneto route.

These are lovely bits of kit! Beautifully made, and have all the benefits of modern electronic ignition, but inside a self generating magneto body.
No reliance on the alternator and battery to get me home!!



The magneto is a perfect fit, and looks great!

It's an absolute breeze to fit - just insert the locking pin on the magneto, rotate the engine to 38 degrees before top dead centre and then tighten the pulley on the end of the magneto down onto the taper (only the bottom one has a woodruff key - the top one relies on an interference fit).

You may have noticed in the last post that I said pulley instead of sprocket...
...that was entirely intentional!



I had made it my mission to run this bike without any chains at all, and this was the first major modification.
When we had disassembled the engine, we had found that at some point the timing chain had broken - there was a huge amount of damage inside the timing case, and we spent a long time dressing the aluminium to get the scars and damage out.

When it exploded, it had smashed a hole in the timing cover, and the previous owner had found someone that made an excellent quality repair to the cover. The quality of the repair was probably the best thing about the bike!



I had seen the Cammy Norton boys using nickety belts and pulleys on the magnetos of the Manx's so thought I'd give it a go.



The pulleys needed a LOT of fettling and modification in order to get it to fit, and some experimentation with belts, but eventually I came up with something that looked great, and seems to work very well.

Certainly attaching the end of the drill to the crank and turning the engine over as fast as the drill would go proved that the belt ran true!

The next job was to fit an aluminium union to the crankcase breather pipe



I had spent a LOT of hours research crankcase breathing and had several conversations with Rex Bunn (bunnbreather.wordpress.com) about the research he had done.
I had got one of the Bunn Breather kits, with a view to fitting it on my bike, but whilst the special material he had used for the valves was more expensive than the equivalent weight in gold (his words not mine) I was really unimpressed by the quality of the valves. They looked like the little air valves you put on the air brick of an aquarium pump.

One of the valves would be attached to the crankcase breather.
The second would be attached to a hole i made in the rocker cover.



I thought i could do better than the Bunn valves.

So after more research into what was around, in the end I went up the Krank Vent (http://www.et-performance.com) route, but applied the research and logic from Rex Bunn which I thought was sound.

The idea was to have two points that the air could be sucked in, and blown out.
With a valve on each, one would be the air inlet (at the crank), and the other would be the air exhaust (at the rocker cover)

Blowby gas would vent to air via a little catch can hidden under the fuel tank.

I blocked up the hole under the crank shaft (drive side) - another source of an annoying leak



I spoke to several people about this, and they all said i was safe to block this up, given my plans on engine breathing.

I used a small grub screw, then screwed in a little bolt onto it it lock it in place.

The next step was to fit a cool little oil junction block that my Dad made.



We have had a massive lump of Aluminium kicking around in the shed for as long as i can remember, and he kindly used a piece of it to whittle out this nice little addition.



Much better than the original oil junction block it was replacing!!!

Re; “I had seen the Cammy Norton boys using nickety belts and pulleys on the magnetos of the Manx's so thought I'd give it a go.”

So, here is someone else using up valuable resources to make toothed belts, no wonder a new rear drive belt for my Kawasaki GPZ305 is so expensive - £220 the last time I looked :!: :shock:

@Bernhard the belts for the magneto weighed in at around £3-£4 each. Once I worked out the make I was going for (based on specifications and properties) I picked up three different ones and experimented with the length/tension.

...yep, I am the last of the big spenders!!!

I've never actually heard of a magneto timing chain breaking - maybe the spring link wasn't done correctly. ?
All greased up in there, they don't exactly wear out or wear the sprockets until a big mileage either.
Nothing like a bit of bling for a low tech application though !
Wait until the next owner tries to source a new belt....

Nice looking cycle coming along there.

@Rohan it's actually a very easy to source belt 10mm wide T5 - these are used a lot in industrial applications, and are available off the shelf for 4 quid!

It was the engineering challenge as much as anything... I'm sure the damage previously was simply caused by lack of maintenance (the old sprockets were shaped like cowboy's spurs, so it had seen a LOT of wear) and/or poor chain tension.

I was actually thinking what happens in 40 years, when the next owner(s) start hunting for a belt thats not listed in the parts book.
But if they are that cheap and plentiful now, maybe they will still be around....

So with all the main engine parts assembled, it was time to re-torque the head (there is a certain amount of stretch in the studs by design, so it takes a few heat cycles, a good amount of time, and several re-torques before it settles down)

Re-check the the pushrods - pretty easy on an ES2 engine - when the pushrods are at their lowest position, you should be able to freely rotate them, but you should not feel any looseness (slack) between the cam followers and the rockers

Next I could move on to fitting the Carburetor.

I got a new Amal Premier Concentric - i was lured by the promises of the improved idle circuit, the anodized slide and the better quality!



I popped in to Burlen Fuels (who own Amal) and had a really good chat with them - they are about 30 mins from where i live, so it was pretty handy!

Whilst my bike would have had a Monobloc on it originally, the Concentric seems to be a pretty well accepted alteration for the better!

Even though i had spend hours refurbishing the carb i took off, it really wasn't the right one for the bike anyway - it was the right side of a pair of late Commando 850 carbs (932/42) and 32mm was actually way too big for the engine anyway.

It had been jetted to suit, but was really a bit of a mish mash.

So a new 928 Premier it was!

Dad kindly polished the covers until you could see your face in them.



Over the years, not only had the aluminum dulled and gone cloudy/milky - but there were also some pretty deep scars and war wounds on them.



He dressed them, sanded them, and polished them up, and I am really pleased with how all the cases and covers came up!

All the ill-fitting paper gaskets were trimmed with a sharp hobby knife.

And that's it for this chapter - the engine rebuild was complete.



I was really pleased with how the build went, and whilst some of the parts were hard to get hold off, the quality was good, and the assembly went well.

Yep, this engine would look good in my café racer - or should that be poor man's manx?

Hmmmmm, and that was the comment that got me thinking...
Poor Man's Manx
...and as usual, my Dad and his friends were the antagonists/catalysts.



Stop the press - was it time for a rethink?

All through the project so far, I had endured many comments like these:

• That would be better with a Triumph Engine in it
• That would be better with a Vincent Engine in it
• That would be better with a Harley Engine in it
• That would be better with a Honda Engine in it

In fact the comments had got so frequent, it had made me even more determined (read bloody-minded) that i was going to stick with a Norton engine, and make it something to behold!
It seems these days, that it is in fact a novelty or becoming increasingly unusual to see a Featherbed with a Norton engine in it!!!

I would say I'm a Norton guy.

I like the brand, I find the history interesting, I love some of the models (admittedly not all of them!)
I have also enjoyed watching the various resurrections of the brand over the years!

However, with my bike I didn't want people thinking i was trying to be something I'm not.
I didn't want people looking at it and say "oh, there's the guy who thinks he's got a Manx)

The Manx is my favorite bike - I love it

I love the looks, I love what it achieved and I love the sound!

However, this is a £25k bike and is not a Sunday morning bimbling machine!
Which is why I went for the ES2

But my ES2 built up café racer style would always be perceived to be something it isn't, and will never be.

What to do, what to do?

Then i had a call - completely out of the blue, from a guy in Germany that someone i work with put me in touch with when i was looking for some wheel hubs.

Did I know anyone that wants a Commando Engine?

Hmmmm....

gtiller said:

Next I could move on to fitting the Carburetor.

I got a new Amal Premier Concentric - i was lured by the promises of the improved idle circuit, the anodized slide and the better quality!

Click to expand...

Did Burlen sell you the tea strainer on the air inlet?

Expect serious mixture problems.

Glad you stuck with a Norton engine in the Featherbed, it don't matter what Norton engine but keeping it all Norton is the only way to go, can't wait to see it all together and if it looks as good as your old Dommie as well the other bikes in your pics.

Ashley