Making the 650 HunterBird

[alan.moore]

Keep the updates coming

Cheers
Alan

[tonyh]

Yes there's plenty of these brakes about and not to expensive. I would have liked an 8" single sided BSA one, but its a special so I may as well put what I want in.

The Back wheel I used a Suzuki T500 from the 70's. This, like the Ariel wheel has the brake on the opposite side to the sprocket. Although a steel rim it was 5lb lighter to. The wheel can be taken out and the sprocket left in place. It also has an excellent cush drive system. Along with the engine cush drive it should take all the harshness from the transmition. The tyre like the front, was an almost new Roadrider.

[Steven.Carter]

Very interesting. Thanks Tony

[tonyh]

You may have noticed the the rear chain gaurd. This is also Enfield, another ebay job from India. It was £11.95 free delivery. It comes painted, but I will redo this and the rear bracket near the rear damper even lines up with the one on the gaurd. I have used these before and there very good.

[Keith.owen]

Hi,
This is fascinating. Keep it coming!

I am intrigued by how you fit the wheels since I guess the spindles must need re-machining to fit the Ariel fork legs, swinging arm?

You have my respect.
Keith

[JohnnyBeckett]

HI Tonyh i like the rear wheel it goes very well with the age of the bike i have been using Japaneses wheels but i like the Enfleld font wheel you have used that is what i am going to look into next for my one keep the posts coming

[tonyh]

Because the Ariel Wheel spindles, both back and front are so big, it's quite easy to make spacers to reduce them to the correct diameter. The back wheel complete only cost £60 from a breaker with the brake etc. Its 18" not 19" like the front.

The rear sprocket was only 38 teeth. I wanted about 45T. However a little internet search found a 44T one new with the right centre hole and hole pitch for £20 which bolted straight on. The Chain is 520, that's 5/8 x 1/4 in old money. The chain is an Xring type so should last well. As MotoGp and WSB etc use this chain I think my 35BHP should be ok.

[tonyh]

I did have access to a Burman Huntmaster gearbox with the longer mainshaft but decided to use a Triumph box.

There's nothing the matter with the Burman box. Its bit slow changing, but strong and will last us all out. However, I have a lot of pre unit Triumph stuff including a number of g/boxs. Some have 4 speeds some 5 speeds. The 5 speed T140 gears, shafts and bearings fit straight in the shell with no machining and I have made several over the years. All you have to do is shorten the lever movement or it will over / under change.

The other good thing is the 5 speed ratios are even. This means you can over gear a little and use top as an overdrive. Also, the lugs on the top and bottom aline with the rear of the Triumph crankcases lugs.

The motor is a small bearing dynamo engine from the early 50's.This has the dynamo at the front like the Huntmaster motor. I will use a Triumph chain case as well and the trick is to fit the engine and gearbox with chain case in the Ariel frame as low as possible with clearance front and back.

I used 5mm mild steel plate which I scrounged from a sheet metal unit close to where I live. I made some cardboard engine plates for the rough shape and drew round them to mark out the steel. Well. I think they were made of armour plate as it just turned all my milling cutter blue, even with coolant on so it was hacksaw, muscles and two days of toil.

The bottom of the triumph gearbox pivot to the mainshaft centre is very similar to the Burman and all I had to do was put a reamer through the bottom pivot hole to fit the Triumph box in. With a couple of spacers the rear sprocket lined up on the original wheel with just a couple of mm offset. I had to make all the nuts and bolts too.

I managed to get the engine in and dynamo plus the chain case with just enough clearance. I worked it out I had about 3mm to play with. I used an empty set of cases at this stage as they were a lot lighter than a complete engine unit.

I will post another picture from the other side later.

[tomwalker]

I am in awe of your resourceful skill and ability to make things fit. This is fun to follow and inspiring me to get on with my projects!

[Leejm]

The burman gearbox is a good box. In fact I will go the say its a much better box than any of the bsa boxes I have had. The main problem is the clutch its just too heavy takes too long to slow down to change gear without crunching. If the clutch weight could be reduced by a fair amount changing would be much quicker.