Pullit Bullit Tool …

TOP Top Tip – ‘ The Pullit Bullit ‘

Changing cable outers on a Vespa can be a pain in the bum if you don’t know how to do it and ridiculously easy if you do.

This tool will do two jobs – it will change an outer cable if you already have an old outer in place (silly easy) or even install a new outer if there is no old outer in place (fairly easy)

The full tool consists of a nice thick outer cable ( mine is a Lambretta clutch cable outer) and a special inner cable that you will need to make. Simpler versions will work but this is my posh version because I am a tool tart.

You need an inner cable that is just over twice as long as your longest outer, you need a clutch cable trunion and you need a brass bullit end. The brass bullit thingy is drilled with a 1.5 mm hole so the cable can be soldered to it and then counter bore the other end to 6.5mm. My bullit is 8mm in diameter.

Solder the brass bullit to one end of the long inner cable, cut it flush and then file it until it is smooth. The other bare end of the cable should also be sparingly soldered and filed smooth.

Fitting a new cable outer if you have an old one is a piece of cake. Pull the old inner out – thread the bare end of the long cable in until the brass thingy is snug, thread your new cable outer onto the bare end and then join the whole thing together snug by using the ferrule. You will now have 2 cable outers joined bu the one long inner. Pull the old cable out and it will draw the new cable in , its that simple.

If you have no old outer in the frame ( paintjob for eg ) then put your bullit inner into the lambretta cable and then make snug with the trunion / cable clamp. Push it through the frame , the shape of the bullit and its bit of weight is a huge advantage. Once its through remove the trunnion as before and thread on your new outer , attach trunion and pull new outer back through – taddaaaa !

Easiest place to get a long cable is a bicycle shop and ask for a tandem rear brake cable.

The bullit you will need to make but if you have an outer already in place then you can do without the posh brass bit and just use a trunnion each end.

I wonder if I should make these up for sale ?

Spannered …

Top Tip – Spannered ?

Some of my ratcheting spanners don’t have levers to change direction but require you to turn the spanner itself over. One way for clockwise and the other for anti-clockwise.

This gives you a 50/50 chance of getting it right first time – yeah fat chance , ALWAYS the wrong way round for me first go.

I decided to go for a high tech fix – a quick bit of paint and then wiped off with a kitchen towel so the paint is only in the etched parts where it wont so easily get rubbed off.

So now my painted sides and clockwise and my unpainted anti-clockwise. Simples.

Inlet timing …

Today I have been measuring inlet durations. The original Piaggio homologation papers for a 50 Special dated 1972 shows the inlet timing as open at 90 degrees BTDC , closes at 40 ATDC for a total inlet timing of a truly awesome 130 degrees.

So I dry built my bottom end and setup a degree wheel on it. The timings on my engine are EXACTLY as per spec- to the degree.

Hit the deck …

There are a few reasons why you might need to know exactly how far below the top of the cylinder your piston stops at TDC but the most common reason is if you want to calculate your port timings mathematically.

This is made harder than usual if the piston has a very crowned dome and this is my method for dealing with it. Bolt a very flat bar across the top of the cylinder and let it go as far across the bore as you can without interfering with the crown at TDC. The simply trap some solder under the edge just as if you were checking your squish. If you don’t have thick enough solder it is possible to twist 2 or even 3 strands if needed.

In this example you can see my piston stops exactly 1.02 mm from the top.

NB – For best accuracy crush the solder inline with the gudgeon pin.

Tool tip …

Yet another of my ‘Top Tips’

This one is different though as you almost certainly do not need this one unless you have way too much time on your hands.

One of my pet HATES is a conrod bashing against the cases when building an engine. I usually get around this with a simple rubber band but on the short stud engines this has a habit of coming off too easy. So simply take a piece of plastic, thin mdf or hardboard etc and knock one of these up.

I have been doing a lot of dry engine building of late and this has been super handy – fits on just two studs so it works with just the one case half or both.

Primary ratios …

I have deliberated a fair bit about which primary ratio to go for but I think now I have a plan. As you all know it is a engine split job to change the larger primary gear so having some options for the smaller pinion is extremely handy. I decided to start with a 16/68 which gives a ratio of 4.25 to 1. DRT make a 15 and a 17 pinion giving me the availabilty of 4.53 and 4.00 to 1.

It is fairly hilly around here and I am seriously considering using a 3 speed gearbox so I have decided to go shorter than the 3.72 as fitted to the SS50 and the 50SR.

Clutch cable bracket …

Today’s Top Tip – 6mm clutch cable adjuster.

I recently got hold of a used clutch cable adjuster bracket for my build that was a lovely price but the thread was dodgy. As you know Piaggio decided 5mm was enough for this job – not sure that I agree with them to be honest.

Now you can put a nut either side of the bracket and it will work just fine but does make adjusting the clutch a little bit more of a fiddle than it needs to be.

The solution is simple enough. SiP do a 6mm adjuster for very sensible money – so the remains of the old thread can be drilled through carefully , cut a new thread using a 6mm tap , fit new adjuster , job done !

Now a second nut on the other side of the bracket is still a good idea to snug down once the adjustment is done to help take the load off the thread in the ’too thin for a thread’ bracket.