This is going to take a while but Tarka asked...
The question of exactly what it is has never really been cleared up. I bought it at the Bonhams auction held at the Stafford classic bike show without actually being there and the description said Montjuic but my head said don’t trust it so don’t pay much. I picked it up about 2 hours later but I did ride it from the auction room to my van
As anyone around at that time knows, they’re the Slater Brothers baby version of a Jota, somewhere between an Alpino and the Formula 500 race bike and kind of road legal. According to the log book this one is a 1978 Alpino S which means it was the first stage of the Montjuic evolution before they named them the Montjuic MKI & MKII. A 1978 model should have had the handlebar mounted fairing from the MKI and a different seat, mine has the MKII parts so I assumed it was a made up one but lacking the engine internal changes.
I had the cam cover off to check the valve clearances and check which cams are fitted and they’re definitely the higher lift, longer duration S1 camshafts so that’s a bonus. I stripped and cleaned the carbs but they didn’t send that extra jet of fuel through as a pumper is supposed to do at bigger throttle openings so I bought a repair kit. Still no joy so I bought new carbs along with a selection of jets and they worked perfectly. At that point I checked the compression and it was up there in Montjuic territory so another bonus. It doesn’t have the close ratio gearbox that the Formula 500 was given so it didn’t start life as one of those.
Next step was the exhaust. The original was a fucking mess of rotten mild steel with plates welded on to fill holes. I tried to find someone who’d copy it for me and was about to bite the bullet and pay a lot of money to a Dutch guy reputed to make shit hot Montjuic 2:1systems when I was offered an original Sito 2:2 that was solid but needed some heat resistant paint. Job done.
That meant it ran reasonably well so I ran it around for a while but the rear shocks were rubbish, the electrics were nearly 40 years old and the paintwork was abysmal so I bought a pair of Ikon 7610 shocks which helped a lot. The bodywork went to a friend of a friend to be sprayed and it’s a perfect colour match, lovely deep finish but with fucking overspray inside the filler cap
Once the bodywork was back I sent it for a full rewire which is a work of art to look at but brake light switches? Not there because a dull head motorbike magazine photographer who knows me told the guy doing the job I’d be racing it on the roads in European classic races
By then I’d got a spare set of wheels to refurbish and fit wets on when circumstances called for them, spare footrests and a couple of other bits and pieces but no valid MOT so it’s sat around for 4 years while other things have overtaken it and I’ve not had the time to take it to Chimay, Gedinne etc.
The wheels need sorting out, brake lights need doing but the guru only lives 10 away so that’s easily cured if I don’t put banjo bolt pressure switches on and splice them in myself.
So, Tarka, is it a Montjuic, what MK is it, in fact what the fuck is it? According to Slaters it was an Alpino S (as stated on the documents) that the owner took to them and told them to make it into a MKII Montjuic in every way after he crashed it and duffed up the footrests, handlebars, seat and tank in a no fault accident. It’s real but it’s not on their ‘official’ register of Montjuics because it was never actually made as one. They kept a list of every Jota and Montjuic made so anyone looking to buy one can check if it’s genuine or not.
If I don’t race it I’ll probably use it once or twice a year which is all well and good until I want to put something else in the Monty shaped gap in the garage. I won’t use it for UK track days because it’d be like putting a target on my back but a run out at the Spa Bikers Classic weekend every year would be fun and I could take three bikes over in my van
Paul - basic servicing is all they need but they’re bastards to ride with a narrower power band than a road going 2 stroke from that period.