Bimota SB2

The beautiful silhouette of the Bimota SB2.

In the incredulous words of ‘Talking Heads’ ironically titled, “Once in a Lifetime” song, “Good God…….what have I done?” As I sit here trembling from nervous energy, I’m excited, ecstatic, nervous and bricking it, all at the same time in countering waves. I’ve just placed a deposit on a once in a lifetime bike. A bike that I was smitten with from the first time I clapped eyes on a picture of one…may soon be turning into a reality.

Supplied by Chris Mayhew of Lusso Veloce (est. 1973 as North Leicester Motors ‘NLM’)

It’s a totally impractical proposition and will be the most valuable bike I own, hard to justify on any logical level as a ‘motorbike’, but this truly is so much more. It’s not ‘just’ a ‘motorbike’ although it is that, and a fine one at that. It is not just ‘art, although it quite easily qualifies for this, it’s not just an ‘engineering masterpiece’ for it is also this too. It is the origin story of the greatest and arguably most influential motorcycle designer/engineer that has ever existed. A man that defined at least four decades of motorcycle creations. The genius behind Bimota, Cagiva, Ducati and MV Agusta’s finest models.

I am a huge fan of Massimo Tamburini. It runs much deeper than this though, there’s an aura of energy that radiates from his machines, one that ignites the kindred soul within, an affinity for what he set out to achieve and an admiration for his engineering execution to meet those big visions that he dreamed for himself. I share this empathic bond with the great man when in the presence of his works. It’s about having an appreciation for his engineering prowess, always pushing the envelope and breaking with convention for nothing more pure or sincere than a love for the pursuit of excellence and beauty on a granular level.

Massimo “Max” Tamburini carrying out evaluation work on his first production road bike…

His intense attention to detail pushes everything way beyond what was strictly necessary or commercially viable, driven by a true passion to create perfection in the process, channelled through an unwavering dedication and a focused determination. This is, motorcycle art! I admire the execution of the solutions he devised and find myself in awe of the detail evident in his creations. There are so many little touches, nuances, traits that strongly pervade all of his works, works that are defined by boldness, risk, courage, sacrifice, passion, intelligence, imagination, love, perseverance, energy, precision and excellence. It is engineered into the DNA of all of his motorcycles, only truly visible to those who truly appreciate.

It is widely claimed that 140 SB2’s were produced in both kit and factory form. The figure for factory bikes would be far less. How many remain today is unknown, 40 have been registerd in total on the Bimota owners register.

The Bimota SB2, is the first complete road bike designed by Massimo Tamburini, hot off the heels of his direct contribution to the Bimota framed Championship winning Yamaha powered motorcycle of Venezuelan Johnny Cecotto who won on the opening race of the 1975 350cc Championship and finished the year defeating the legendary and undisputed Seven time defending champion, Giacomo Agostini, providing Johnny with his one and only 350cc World Championship crown.

The prototype featured underseat exhausts which ran above the engine and underslung fuel tank cited below the engine. Heat management meant that he couldn’t get this design to work suitably for production. Underseat exhausts would have to wait a couple of decades.

Having established his own company, ‘Bimota’ in 1972 with 2 other friends (Bianchi/Morri/Tamburini) initially as heating system engineers, it was soon renamed Bimota Meccanica in 1973 when they began producing race chassis frames for racers. Buzzing with the victorious energy and the confidence from his race success, Tamburini turned his attention to Bimota’s first road bike, the groundbreaking SB2. A ground up motorcycle which was exhibited to the world for the first time at the 1976 Bologna Motorshow.

The Bologna Motor Show 1976 where the SB2 was first exhibited. Far Right Giuseppe Morri, Second from right Massimo Tamburini sporting a fine 70’s moustache!

This model carried the pressures, the success, the hopes and dreams for the future of Bimota. This was Tamburini’s Genesis, his first true creation. As such, it is possibly one of the most interesting and exciting motorcycles produced in my timeline. Conceived and born at the same time as me, this fabulous creation is my motorcycle doppelgänger.

A clean rear end utilising a monoshock design on a rocker linkage. No dual shocks at the rear end like most 70’s designs

1976, and here was this radically designed motorcycle that looked to have come from another planet compared to contemporary forms of the time; all swoops, curves and presence, patiently and lovingly sculpted, applying his all, the bike encompassed so much more than the beauty it’s bodywork exuded, for it contained within its wrapper many world firsts and concepts which remained a Tamburini hallmark throughout his career.

Faired in indicators, one of Tamburini’s stylistic penchants…

As anyone who has worked on one of Tamburini’s great designs will appreciate, the intelligence of his creations manifest themselves the very first time you begin to disassemble the components to carry out maintenance. The bodywork always comes apart incredibly easily. As an owner, it is highly rewarding to strip the motorcycle down to it’s frame and engine in moments.

The easily removeable fairings reveal the clean chassis with exceptional access to the engine workings.

Going even further, it’s not just ease of access to serviceable items; consider the frame for instance, which uses the engine itself as a stressed member, it is designed so that it can be detached from the frame in mere minutes.

A young Giuseppe Morri and Massimo Tamburini

Beautifully engineered conical fittings provide strength and precise mating of the components while providing a substantial visual statement of intention, not just providing supreme rigidity, but boldly making that point with a heavily engineered joint for reassurance.

The beautifully engineered and executed conical fixings, featuring three bolts each located on either side of the frame providing the incredible chassis rigidity.

The rear end, uses an eccentric hub to adjust chain tension. This features in so many of Tamburini’s designs, the original Ducati Paso had the same setup, along with the later 916 and F4 which both additionally featured a single sided swingarm with the eccentric hub.

The eccentric hub meant that as the chain is adjusted, the rear ride height will change. Of course Massimo Tamburini had allowed for this with a compensation rod connecting to a rocker in the rear linkage to adjust the ride height precisely back to where it needs to be.

The rear swingarm pivot point, was aligned with the gearbox output sprocket, this allowed the rear end to maintain a constant chain tension throughout the arc of the swingarm’s movement and more importantly, all but eliminated rear squat under power. The use of the rear monoshock is also one of the first road bikes to deploy this setup.

Suzuki electronics matched to the powerplant.

At the front end, an eccentric hub in the triple tree allowed the offset to be changed to tune the steering response. This idea carried through to the F4 also. The forks were set in at an offset angle to the yokes (28 degrees from vertical) as opposed to the triple tree (24 degrees from vertical) to reduce rake/trail changes under braking for a more consistent geometry.

A young Tamburini works on an adjustable SB2 triple tree.

35mm Ceriani telescopic front forks and a Corte é Cosso rear shock absorber handled the suspension movement.

For deceleration, Brembo provided the braking power with twin 280mm rotors up front and a single caliper 260mm disc set up at the rear. These were married with Magnesium Speedline rims, fitted with the modern day equivalent of 100/90/18 to the front and a 130/80/18 rear tyre.

Suzuki provides the beating heart within the chassis. An 8v GS750 750cc inline 4 cylinder engine allied to Suzuki electronics and a 4 into 1 free flowing exhaust system are fitted as standard to the factory bikes.

As a factory upgrade option, one was able to specify a Yoshimura 850cc engine as fitted to this particular bike. Yoshimura were a renowned Japanese engine tuner, synonymous with Suzuki courtesy of the solid reputation they had earned from all their racing success with tuned Suzuki engines.

This reworked powerplant featured an overbored Suzuki block fitted with Yoshimura 69mm high compression pistons.

Yoshimura 69mm Pistons as fitted to the 850cc Option Engine. Photo credit: Made in Italy Motorcycles

Yoshimura Road and Track camshafts were installed with race valve springs complimented by a Yoshimura ported cylinder head which in turn was fed through a bank of Mikuni 29mm carburettors replacing the standard 26mm items. This upgrade brought power up to 100hp at the engine, a significant increase over the stock 75hp engine output.

Yoshimura Road and Track Camshaft as fitted to the 850cc Option Engine. Photo credit: Made in Italy Motorcycles.

Beautiful details abound, with aircraft grade aluminium featuring everywhere, from die cast footpegs and controls, to the front yokes, rear hub, sprocket, fuel filler cap with enough little machined ‘Bimota’ logos positioned to remind you just which company manufactured this fabulous motorbike, setting a whole new standard for chassis design and exquisite detailing.

The SB2 represented a cut above everything else commercially available, placing Bimota squarely into a boutique niche that it would occupy for decades to come with the Bimota SB2 providing the firm foundations for Massimo Tamburini’s illustrious career while simultaneously raising the bar for the rest of the motorcycle industry.

It’s Electrifying!

While trying to resolve the cold starting difficulties, I notice a sound coming from the front of the bike. It sounds like something short circuiting. The bike is fitted with an aftermarket HID conversion low beam which comes on with the ignition. After tracing this noise back to the low beam, I start dismantling the front nose cone. Unfortunately I forgot to take a photo of how cool the wing mirror wiring setup is!!

It’s a pity as the HID worked very well, however it has to go…

I’m fortunate that the starting problem has led to me finding this…

The plastic cases containing the high voltage components were crumbling away, cracked and broken…

Hmmm… 23,000 volts!!

The HID kit is stripped out in its entirety, the stock bulb that came with the bike goes back in its place. I don’t use this for night riding, if I find the stock lamp to be a problem I may look into an LED kit, for the time being I’m just pleased that disaster has been averted!!

Stock bulb back in place…note again how cool the bulb access point is…

An MV logo’d rubber cover piece inserts into this bulb access hatch 🙂

Prima Donna…

In true Italian motorcycle style, they let you know when they’re not happy and require continuous pampering. After draining the old fuel out and filling with fresh SUL, a month later she’s grumpy to start again. I take the opportunity to order a new fuel filter (even though this was done 20 months prior and not even a full tank ago).

Masking the tank and airbox up to protect the paintwork…

A thing of beauty, the more you delve in the more you discover. From the intelligent way it all comes apart easily to the quirky design touches that you just don’t see on mainstream bikes. These are typical Tamburini traits, a design genius; combining the aesthetic beauty with mechanical thoughtfulness.

Like most Italian bikes, the MV is fitted with quick release CPC plastic fuel quick release connectors. These are known to embrittle with age where they can break and lead to an inferno as fuel sprays all over a hot engine.

With the tank off it’s time to swap these out for the more reliable metal bodied CPC units. The fuel hoses should also be replaced every three years according to the workshop manual, so once again, I’ll take the opportunity to upgrade. Plastic connectors below…

Typically, what should be a 5 minute job of unscrewing the plastic and replacing with metal turns into a mini marathon…one of the connectors snaps, albeit somewhat predictably…fortunately it came out cleanly enough with a splined extractor…

The offending plastic items…

Replacement metal bodied CPC connectors with Viton seals…

I take the opportunity to re-align the wiring to the correct orientation where they should exit towards the front of the pump housing to make tank wire routing and removal easier.

With the pump out, it’s time to clean out the debris from the inside of the fuel tank…

There’s a surprising amount of debris in there. It all cleans up easily enough though.

Fuel pump/filter assembly…I’ve checked all the internal tank lines that were renewed 20 months ago, I haven’t replaced them this time, but have ordered some new Cohline in tank hosing for next time. The fuel filter looks newish, but with the debris in the tank I decide to take it apart to check…

It actually looks in pretty good order…

Everything gets a thorough cleaning, including the pre filter

And re-assembled as per the workshop manual with a new fuel filter installed…

The gasket is smeared with silicone grease and the fuel pump base eased back in…note the breather hoses which don’t have much lenghth on them and require reconnecting in situ…

That takes care of the tank side for now. Next time in I’ll be replacing the internal tank hoses with this item…

I’ve taken reference dimensions while everything was out so I can cut it all down to length in readiness for next time!

On to the fuel rail and hoses. Once again, the hoses are fitted with plastic CPC connectors and one of the hoses has a surface nick in it.

I have some custom hoses made up. These are XRP Pro Plus XKS -6 Plus hoses. They are a 3/8 equivalent with -6 fittings at either end. The hose itself consists of an anti static PTFE smooth bore inner hose with external convolutions for tight bend flexibility with an Aramid fibre with silicone outer braid for easy cleaning.

These are mated to the corresponding valved metal CPC’s with dry breaks on the fuel pump plate and at the hose end.

At the fuel rail end are some plastic SAE J2044 quick connectors which replicate the originals.

Peace of mind!!

Once again she fires up on the button, but she seems to be quite finicky with fuel. Having eliminated the fuel, pump, filter, hoses, it’s time to look elsewhere at the fussy cold starts with anything other than fresh fuel.

Manufacturer labels on the fuel tank show it was painted in the 23rd January 2009, including the painters signature!!

Hoses in position and in place under the tank…no more fears of them snapping on disconnection!!

Black, round, Pirelli’s…

After 20 years it’s time for the RS and the original fitment Dunlops to part ways…it’s an Italian bike, so Italian tyres will be going on this time…in the words of Juha Kankunnen, I have opted for black, round Pirellis. Diablo Rosso III’s to be precise, which are my favoured road tyre of the moment.

The original Dunlops still rode well, however the history showed the rear one had been plugged, and so it was, on removal the plug was still there!

Of course, while the wheels are off it would be rude not to inspect the front calipers and pads and also deep clean the swingarm area.

There’s not much wrong with the calipers. I have bought a replacement Brembo caliper seal kit but this will have to wait a bit longer, along with the new front brake master cylinder as I’m itching to get this on the road now. For today it’s just a clean up of the pads/gubbins and clean and regrease the pistons.

The rear comes up nice and shiny…

The gearbox

The gearbox oil was last changed about 400 miles ago, and about 20 years!! So despite looking reasonably clean I drain it out for replacement. I drain out over 800ml.

The oil plug is also relatively clean.

Cleaned off and ready to reinsert!

On the advice of the tuning works, I go for Silkolene light gear oil, and fill it to the correct 700ml measure.

However after consulting the manual, it looks like Medium gear oil would be the correct choice! As a result I shall probably drain this out and replace with medium soon!!

From reading the Silkolene data sheets, Gear oil ‘medium’ is the equivalent weight to engine oil SAE 20W/50 as called out in the manual. Gear oil ‘light’ is a 10W/40.

The original crush washer was clearly reused previously and crushed to nothing! I fit a new washer to the correct torque setting.

Edit:

Gear oil light I feel is too thin, so it has been replaced with medium, a mere 40 miles later!!

Testing, testing…

While everything is apart I decide to do a compression test. These can vary widely depending on gauge used etc. My gauge set is designed for car engines and therefore the hose itself is about 10mm diameter. This means that a motorcycle specific meter (Kawasaki gauges have a 3mm diameter hose) would likely yield a higher figure. The more important metric is to check that both cylinders are reading a similar amount rather than the outright figure. With this in mind, the reading looks a little on the low side for the lower cylinder.

However on checking the upper cylinder, the result is much the same, in fact, it’s identical 🙂

The above test was taking with a cold engine. On a hot engine and some more vivid application of the kick starter, both yield 105psi.

The spark plugs are also looking a nice healthy shade after a run.

Although I’ve purchased some Iridium plugs, I haven’t fitted them yet, preferring to make sure it is all running perfectly first as is, then hopefully I can measure (albeit subjectively) any perceived improvements when I swap to iridium.

Beauty is more than skin deep

As part of the deep clean down, I marvel at the way this bike comes apart. The design Genius creator that was Massimo Tamburini has a unique style which is evident in all his motorcycles. My 907ie also designed by him has so many design similarities and little elements of intricate attention to detail that cannot help but leave you shaking your head in admiration and wonder.

The bodywork features quick release Dzus fasteners allowing the side fairings to be removed in seconds…

The rear tail fairing hinges forward and removal of two pins and the loom connector allows the entire tail to lift off. The fuel tank lifts off after removing two side locating brackets and one centre bolt along with unclipping the two quick release fuel connectors and loom connector. The whole bike takes minutes to strip down to its beautiful chassis.

Stunning details everywhere include MV monograms all over,

Lest we forget…

Other neat touches such as this rubber elbow on the water pipe so it doesn’t rub on the fairing…

Or these rubber bracelets around the wiring loom…

And these remote vacuum ports for synching throttle bodies…

The quick release front nose cone is another revelation featuring spring loaded electrical contacts for the front indicators housed in the mirrors…

WTF!

It’s time to bleed the front brakes, the fluid smells vinegary and there is some dirt around the cap to clean up. I flush the system through and put fresh fluid in.

While bleeding the front brakes I have another WTF moment, as I spot another problem!

This time, it isn’t something menial that has the potential to ruin the engine like the previous carb issues or potential oil feed blockage, no, this time, it’s the brake hose banjo bolts! I’m bleeding the brakes and I see leakage from the banjo.

I barely touch the hose end and the fitting spins. The same on the other side. Both hoses are barely finger tight!!!

Once again a reminder of why I do my own maintenance, it’s frightening to think in the last 200 miles this bike has had a service, a sales preparation and an MOT by a reputable bike specialist that even sponsors a race series! Between the nick in the rear brake hose covered by tape and the loose front hoses, coupled with the failed rear master cylinder, any one of these could have been very dangerous but all at the same time wouldn’t bear thinking about! I ordered some new copper washers for the banjo’s and fitted them.

We have ignition…

I’m getting to the end of the preparation now and I’m itching to go out for a ride. All of the Blogs for this bike up until now have involved thoroughly checking the bike over to preempt as many problems as possible by ensuring that this is running as it should be following it’s lengthy lay up and it’s increasingly apparent sub standard recommissioning.

Back to the invoice of the last works that were carried out, when the carbs were done, there was mention of a new plug for the ignition. I looked around at the coils and plugs and could find no evidence of any plugs having been replaced. However while working on the oil reservoir, I came across the ‘Wurth 3 pin connector’ that was shown on the invoice. I noticed it purely because it looked out of place to all the other connectors and looked uncharacteristically large. On closer inspection, the bad workmanship that I’d come to expect from the dealer revealed a wire that was ready to fall out. With no effort it does.

I re-crimp this wire with a new terminal (fortunately I find one of the same size that fits) but then notice the white wire is also similarly badly crimped.

So with this re-crimped and the brown wire checked, this block connector is good to go…or is it?

It turns out that this plug is the ignition signal feedback circuit. One of the checks I was going to do is plug in a Zeeltronic ignition controller (bought specifically for this job) to set up the power valves. Ideally the exhausts need to come off for this check so the valves can be seen in their respective positions. I have bought all the exhaust gaskets to do this work however for now I’m going to get a couple of runs in first! The power valves appear to be operating fine and even the markings line up where they should. However a quick test run with the zeeltronic unit is thwarted because this Wurth connector, happens to be the same plug that the zeeltronic connects to…

This means that the Wurth connector will need to be replaced for an OE block connector which I have now bought.

Happily, this will put the bike completely back to stock and is the last of the hashed items for me to remedy!!

More to follow once the connector is replaced!!

Oil be back!!

Yes, here we are again, this time, having topped off the 2T oil tank, I discover a leak from the level sensor. This will explain the out of place looking jubilee clip!

I take the opportunity to start fresh. Fully strip, remove, clean and refill with my chosen 2T oil, Silkolene Comp 2 Plus.

The oil filter is in a bit of a mess, and in cleaning the tank, I find the remnants of the seal tab of a previous 2T oil container.

This could have easily of blocked up the oil supply so once again, it has paid dividends to go the thorough approach and strip it all down. Also in evidence was silicone sealant that had been gummed around the level sensor, remnants of which had also made it into the tank…

I put some diesel in the tank and slosh it around to capture the final bits of debris…

New filter fitted…the old one cleaned up ok so I’ve kept it as a spare.

To cure the leaking oil level sensor, I place 2Nr 16mm x 1.5mm O ring seals on the level sensor to seal it correctly. This works perfectly.

I test this by topping the tank up to the brim and tilting the bike forward on the Abba stand into the stoppie position. Oil leaks out of the overflow/breather hole, but not the level sensor!

That’s one more thing ticked off the list. No more oil leaking down over the rear of the bike.

The final check, is to open up the purge screw to bleed the oil pump and ensure there is no air in the system…