MB TS1230 5 Speed engine x

There has been 5 speed gearboxes for years way back to the 70's! All Italian and all very err crap! They didn't last 2 minutes before the teeth or selector would strip and that would be it. They got resurrected by Tino Sacchi and Cambridge, but the news was they couldn't get off their estate before they broke, anyway our 5 speed gearbox has nothing to do with the Italian versions.

I commissioned them to be designed and manufactured in the UK. I wanted them to be a semi mass produced gearbox for everyone but it wasn't that easy! First off there is very limited space to add a gear! Then you need to get the gear ratios where we need them.

It's quite a story, all very technical, interesting for some and boring for others.

When something like this gets designed there are so many things to think about, I entrusted the tech design to a company who makes one off race gearboxes for lots of bike engines, they have even made parts direct for Japanese bike manufacturers when they have needed one off gearboxes for certain tracks in Europe along with IOM TT bikes so the manufacturers know their stuff!

This does not come cheap! The company didn't know how a Lambretta engine worked. It got complicated between road-race engines, motocrossers and enduro bikes. Luckily I knew a little about Lambretta engines so we designed on paper a few scenarios and went from there!

So how do you squeeze an extra gear in? Well I cut up a casing! Then this is where the company came in and using their experience they designed a cluster where the 5 gears where pressed onto a shaft and vacuum welded together, there is no gap between each gear. This gap on a standard cluster is where the gear hopper pushes metal away so you need the gap! Add the gaps up and there is an extra gear, easy! Then it was a case of using an existing 1st gear modified for the slightly thinner 5 speed selector! Apparently my Lambretta gears are the same width as these 200bhp monsters so should be strong enough!

I never even asked for a quote when I commissioned them! When they turned up the cluster, 4 new gears, modified 1st gear and gear selectors were a work of art! They didn't just do one box but two and some spares! And then the price......... wow it was a shock! There is no way at this point that we can put them into production, they are too expensive! For me the price didn't matter the quality was superb!

Moving on I fitted it to my 30+bhp TS1 which was transformed into a motocross Lambretta, on about fun! I thrashed it wherever I went, just to try and break it, I couldn't. It was a bit silly really, flat out in every gear on little country roads over taking all the cars with ditches either side, I wouldn't have had a chance if it locked up, but these things you don't think about at the time, if you did you wouldn't ride a Lambretta.

It needed a road test or two to work out power spread and power delivery to work out how gear ratio rises and drops. This needs doing to suss out when you change gear you don't drop out of the power band. The high powered peaky TS1 engine was perfect for this. Add to it the extra benefit of an engine with a wider power band you can see the potential of a 5 speed gearbox.

I asked the company to remake some different gears with different ratios to spread the gear percentages, which they did in a few weeks amasing! These I fitted to my Pushpak ready for the Spanish Euro......... that ended up having dodgy electronics and I didn't do the Euro, hey ho!

Anyway a very good customer of ours found out I had a spare gearbox and begged and begged and offered a very good price! Well along with a full MB engine I sold it. So now there are two people who own these very special gearboxes, I'm one and the other is our customer. If I was going to sell my 5 speed box then I wanted to build the engine, obvious really, I just wanted it to be right for the customer, it's not one of those parts you just fit!

As it happens it did just that......... every part fitted perfect, the 5 loose gears, the cluster, gear selector and all went on our MB layshaft, it assembled perfect, the gear shimming was perfect at 2mm, amasing but that's what hard graft, design, testing and knowledge does to he who waits!

The engine spec is

  • TS1 cylinder
  • Thicker modified side plug head
  • MB Race-Tour piston kit
  • MB Race-Tour 60mm x 110mm crankshaft
  • MB road tune
  • Early AF flywheel
  • BGM stator
  • MB Race-Tour 46 tooth 5 plate clutch
  • MB 5 speed gearbox
  • 19 x 46 sprockets
  • MB top slipper
  • 35mm TMX Mikuni
  • And all the usual MB internals

When I do engines I spend time interviewing the customer to find what he really wants from an engine! When you find out the customer is 17 stone, you don't go ahead and make a peaky engine, he wanted a MB Dev-Tour to spread or lower the power as well. So it was a case of design the porting spec to spread power, make the engine ride-able, pull the weight and work with the 5 speed box.

To prove it, we set the engine up in our jig and swap pipes to show exactly what the customer can expect when fitted in the frame. As part of the Big Box Clubman development I planned this engine to be finish at the same time as the RT reed engine shown elsewhere in the Clubman information pages.

Look at the graphs its a nice engine especially if you look how good the Big Box Clubman is. It's not a full race engine but JUST gets 30bhp with one pipe.

Hopefully with the right pipe the customer gets what he wants and with the added benefit of a 5th gear! Working on a forth gear ratio of 5.20:1 it should prove to be a nice fun engine to ride! But it cost, which is between the customer and us!

Sorry at the moment we have no plans to make more gearboxes, if enough put their name down I will make a batch of 10! I did make a close ratio 4 speed as well where you can slide a number of different gears on and off the cluster, that's another story!

With the graphs I've used the new MB Big Box Clubman as the baseline Red graph as bhp and Green is torque

5 speed assembly

5 speed on the layshaft

MB Race-Tour layshaft

Modified Gp125 first gear

5 speed cluster

Shows how nice it is

Special 5 speed gear cluster

Each gear is marked up

Road tuned casings

MB Race-Tour 5 plate clutch

Red line MB Prototype Clubman vs MB Dev-Tour The Dev-Tour has been a benchmark pipe for many years, the reason is it works on anything. Ok never designed to be a full powered pipe but one to work on a TS1, cast iron or any alloy cylinder regardless of tune and it does. We spent hours and hours developing adjustable pipes to get the best all round results. Its lasted 10 years our customer feed back is great, SO when you see the new Clubman matching and slightly beating the Dev-Tour it's quite incredible the results the Clubman gives. It gives more bottom end power yet matches the Dev-Tour no problem. The new Clubman gives 27 bhp with 19lbs torque..... nearly perfection!

Red line MB Prototype Clubman vs BGM pipe. This is an experimental BGM pipe I've had for a year which I've been testing. It gives a nice smooth graph which really does make a difference when riding the bike. It's not a production pipe, it's a in between pipe which is actually very good providing you get port timings right. BUT it does not work on every style of engine, great on a TS1, not so good on a mild tune. It's good on this engine though.

Red line MB Prototype Clubman vs Franspeed. The Franspeed is the ultimate in the test for top end power! It just gets 30.1bhp! and gives 21lbs torque. It looses out on bottom end power but really lifts the potential of this TS1 engine.

Red line MB Prototype Clubman vs NK Road. We first tested the NK road pipe on a customers engine which had a total cocked up Monza cylinder! It shows the potential to what the pipe could do with the right engine! Here it shows the Clubman is still best low down but the NK picks up with a power band and the spread is quite good, but hits a brick wall at 8000rpm and dies a death, just like a rev limiter which is ideal for this engine...... just change in to overdrive 5th!

Red line MB Prototype Clubman vs 39mm Prototype. In theory the thinner down pipe should give best bottom end as all the forums think, I've proven on lots of runs this is not the case. BIG is best this time apart from a little better low down

Red line MB Prototype Clubman vs 41mm Prototype. Again showing big is best.

Red line MB Prototype Clubman vs JL3. Again the JL3 or Taffspeed road pipe or going back some the Swift pipe which are all based on the same pipe has been a bench mark people have used for years. I hardly ever hear a bad word about them......... but every time we test them they are the worse pipe on the market for power spread. Here it shows its looses bottom end power but gains in the mid range quite nicely then dies a death and the Clubman keeps going! The JL3 is a good low to mid end peaky pipe but offers no real speed.

Red line MB Prototype Clubman vs 37mm Gori. Here you can clearly see the difference between a Clubman tested, the MB Clubman really leaves the small bore Gori. But the Gori has better power low down around town, they are beautiful to look at and will suit most people with mild tunes.

Red line MB Prototype Clubman vs 46mm Gori. A direct comparison between the MB Clubman and Gori big bore. Not a lot in it, swings and roundabouts! The MB wins low down, its shows a smoother curve with no dip low down like the Gori, but then the Gori has a little more top end, the important torque curve has the same peak! The difference is the Gori is very noisy, not bad with the little end can, but take that off and its very noisy! Where as the MB version is designed with an internal silencer, this is the key to swings and roundabouts.

Red line 46mm Gori Clubman vs 37mm Gori. Again this shows a big U bend is best.

MB 39mm Prototype Clubman vs 37mm Gori Clubman. This shows the difference between our MB Prototype using a small 39mm U bend comparing with a Gori small U bend. the MB version beats it across the rev range, except the Gori is best from 3500 - 5000rpm if that suits you, which it will suit most people. But also look at the torque dip in both pipes between 4000 - 5000rpm this is really bad where the bigger U bends don't have it.

Red line MB Prototype Clubman vs JL4. The Clubman has the bottom end but the JL4 race pipe gives the mid to top end.

Franspeed vs JL4. The JL4 has always been a good top end pipe, based on Taffspeeds and Suzukis TR race engines from the 70's it's always given good results! But the new Franspeed which is very similar but tweaked just has the edge on top end power. Interestingly the bottom and mid range are nearly the same.

This article shows MB are prepared to put our money into development, we always have done from our early days. It's cost lots of money and they may never see the light of day. If enough genuine customers put their money where their mouth is it could become a reality! But in these hard times people want quality without paying. The prices are out of our hands the manufactures are real experts and they have their over heads! There is no cutting corners.

As we go to press there are a few dealers working on some cheaper versions of the 5 speed gearbox! Is it needed? Well it depends on how you look at it and your engine. When you ride a real Lambretta engine and have the benefit of a 5 speed you wouldn't go back to a 4 speed........ it really could be the future of Lambretta engines. I'm now so use to using cars and bikes with 6 speed speeds I wouldn't do without them! Could we design a 6 speed gear in a Lambretta.................. I think so, could we afford to produce them? Perhaps we should redesign the Lambretta casings to take a 6 speed, multi clutch and wider crank with a improved cylinder kit.......... if I can I will, if only its a fun one one.

If you have a question then please Email Mark on mark@seriousoutdooors.co.uk
Mark Broadhurst updated Jan 2012