Another 3 1/2 Sport to return to the roads - soon

[Greybeard]

Hello, Folks.
A new member here just dropping by to introduce myself. Last month I bought a very grubby 1982 Sport from a friend at my sailing club. He'd had the bike for 11 or 12 years but things like house building and boat building distracted his attention and the old K1 lay unloved at the back of a shed for most of that time. The tyres perished (shame as they were almost unused), the brakes grew sluggish and the battery died a slow, miserable death. Prior to that the bike appears to have been superbly restored, the paintwork being immaculate under the grime.
A good wash with degreaser vastly improved the cosmetics and a splash of fresh petrol in the tank had her ticking over nicely. A rather small sum in exchange for the bike was agreed and it headed south from Northumberland to East Yorkshire on the Motolug trailer.
I bought the bike ostensibly for my wife to ride. Despite being of an age when she's entitled to free prescriptions she's keen to get back onto two wheels again. She passed her test 25 years ago and rode my 1100 Virago for a while. Apart from a Teutonic Airhead R100RT my other bikes are all old British iron and whilst she's happy to get astride the 1953 BSA 350, she can't start the thing
The little non-Jap 350 V-twin fitted the bill being a distinctive classic with an electric start and a low seat height. Hopefully it will do the job. At least the gears are on the 'right' side even though they're upside down - and there are so many of 'em!
I've made a start on the front to rear overhaul and had some very helpful contact with Rob at NLM - though I was saddened to hear that this valuable resource is going elsewhere before long (when it will be closer to me if nothing else).
Progress to date has included a pair of new tyres, a full strip of the braking system (triple discs) - I still need to locate a pair of new rear calliper pistons which Rob is looking into for me, otherwise I'll be setting to with the lathe and some stainless steel bar stock. I've fitted new friction shoes to the electric start mechanism and have a new brass worm gear 'on stock' should it fail.
While on the subject, what are the small dimples on the inner surface of the starter drum of the flywheel magneto for? I've also made several stainless steel parts to replace tired looking originals.
I've been quite impressed so far with the build quality of the bike, though I understand that the electrics may be more of a challenge in due course
The last V-twin I owned was a monstrous 1600cc Harley Road King - probably more than three times the weight of this Italian creation and with less than a third of its handling capabilities
The Morini will definitely be a fair weather bike so it'll be giving me plenty of amusement over the winter. Winter is a time for BMW's with huge fairings and heated grips.

Regards. Steve

[Ming]

Hello and welcome. I'm sure you will grow fond of the Morini - they are addictive (and pretty easy to fettle, even the electrics). I trust you have changed the cam belt, that's the one item that can quickly deteriorate in my opinion. It's fairly easy to do. Search for Paul Compton's (evguru) videos on Youtube for lots of 'how to' information.

[EVguru]

While on the subject, what are the small dimples on the inner surface of the starter drum of the flywheel magneto for?

The idea of the dimples is to stop the starter clutch slipping. Many owners have modified the drum in the way over the years. Their actual effect is generally to chew up the starter shoes.

If the starter doesn't thow out the shoes with sufficient vigor, the clutch may slip, particularly if the engine was close to compression.

The battery must be healthy and capable of producing the cranking amps, the starter wiring and relay be in good condition and the motor itself be in good condition.

[Greybeard]

Thanks for the welcome and the advice, chaps.
A new cambelt was the second thing I ordered from NLM - after the magneto puller Whilst the belt that is on looks 'new' it will be at least 11 years old as my mate never changed it when he got the bike. The prospect of a snapped elastic band didn't appeal very much.
I came across the very useful EVguru article on cambelt replacement and the excellent videos via a RealClassics webpage - to now 'have his actual ear' is marvellous. Thanks, Paul.
I did wonder whether the dimples had been an addition. It seemed such an inelegant engineering solution but had been done so neatly that I was unsure whether it was pukka or not. Now I know that it is a bodge I shall remove them. The thought of them chewing away at 100 quid's worth of new shoes would keep me awake at night. Unfortunately the chuck on my Boxford lathe is not quite big enough to get a good hold on the flywheel so plans to skim the drum are off the menu and a careful application of Dremel may be called for instead. I shall consider the plan of attack whilst waiting for the etch primer to dry on the engine cases
My next consideration is whether to replace the black down-pipes with shiny stainless steel ones to match the stainless silencers. We do like a bit of bling. I shall await confirmation of my MRC membership application in the hope that there may be a bit of a discount going by the time the next pension payment arrives

Thanks again. Steve

[Greybeard]

Hello, folks.
I thought I'd update you on progress so far. She's looking a lot smarter than she did when I got her after her decade-long slumber in a boat shed. I've gradually worked my way from front to back cleaning/polishing and making stainless steel bits and pieces. Sorting the electrics alone was a 3 day job. Only the horn button claimed a short lived victory by refusing to allow enough current through to operate the horn - it would however trip a 30 amp relay so had to give in eventually. Working my way through the wiring system (with the help of an excellent colour diagram from the MRC site) it dawned on me why the Italians never adopted the electric chair as a means of execution. They'd need to employ a full-time plug-kicker
There are a few more jobs to sort - new rear calliper pistons are proving elusive though Rob at NLM tells me they are hoping to have a supply soon. If not I'll have to set to with the lathe myself. I've also ordered a set of stainless down pipes to match the silencers - again, Rob hopes to have these before the 21st. If all goes well I may have a complete black system to sell at some point in the future.
Painting jobs still on the list include the nearside engine casing and the rear springs. I'm going to mirror polish the clutch cover to see how it looks. If it's too garish then the satin black tin will be opened up again. Apart from tidying up the instrument bezels, that'll be about it for the time being.
Mrs GB is itching to have a go on the bike but there'll be little chance of that until the winter's over. It'd be a shame to get her (the bike!) wet and salty after all this

Steve

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[3potjohn]

Coming along a treat. I have had a K1 since 2007 and it's been really pleasurable. I have had the motor apart which was nice and easy to work on,given my very limited tools and even more limited garage space. The Morini shares with 2x pushbikes, 2x airheads, many tins of dulux and a goodly selection of airhead gearboxes,wheels,driveshafts and even a spare r60/7 engine. The latter seem like a ton weight compared to the Morini.Note to self:get a better shed.
Mine has a round Cibie headlight,came that way. Seems to work well,though I try not to ride at night if I can help it as too many deer about.
If you can track down a spare transducer and a pickup sometime that would be useful.
My main issue is with the rear tail unit which makes loading camping gear something of a conundrum.I am sure I can hear those Beemers laughing.

[Greybeard]

Thanks 3pj. I shall be keeping an eye open for spares that may come in handy. A member of my local AJS/Matchless group (now in his 80s but still riding 1000s of miles a year albeit on a modern Peugeot 3-wheel scooter) is an ex MRC member/3 1/2 owner and has also mentioned the ease with which the pick-ups can crack if overtightened. My Sport has been fitted with new blue 'coils' so Im hoping it'll be ok for a while yet
Having a few spare airhead gearboxes is a good plan - they are a BMW Achilles heel if regular oil changes are neglected. I needed to treat my RT to a recon box when I got it as the original had been left rumbling for far too long.

Steve

[Ming]

Bike looks great. Please keep us informed on how the Vespa transducers work, though you can build your own fairly easily. The pickup is the biggest issue, as far as I can see.

[Daddy Dom]

Looks great, Greybeard, mine's the same only it gets used weekly. They work so much better that way Your wheels are actually gold!
Keep the piccies coming.
DD

[Greybeard]

Thanks, chaps.
If things go according to plan , Mrs GB hopes to clock up a few miles on the bike, though Im afraid itll remain a fair weather machine but should get a weekly run to the old bike meet Once the EPO (Enjoyment Prevention Officer) has her own wheels I should get more use out of my single seaters
I shall certainly keep you updated on progress and will add pics when we're ready for the road.

Steve

[Greybeard]

Almost there - call it Mrs GB's Chrissy Prezzie. She got the matching sweatshirt yesterday

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I ended up making a pair of stainless rear caliper pistons. I bought a length of 1 1/2 inch bar (38.1mm) which needed just a thin skim off it to bring it down to a mite under 38mm for a good fit. I did try some Suzuki 600 pistons that were advertised as stainless 38mm. When they arrived they were chrome plated mild steel and 38.17mm so wouldn't fit. The chrome prevented any attempt at skimming them too. A length of bar was only 20 quid and I've enough to make another couple of pairs I reckon, though I doubt if this bike will ever be needing another set
Just a few minor tweaks to do yet - I don't like the run of the front brake pipes for a start - mainly cosmetic bits, but I still need to change the fork oil if only for my own peace of mind. I'm still considering whether to treat the inside of the tank with sealer. It's actually in superb condition inside but I'm in the process of sorting a Honda tank out for someone so it'd be a convenient time to do the two tanks.
The local Council were out and about slinging salt around on Chrissy Eve so there's no chance it's going to see tarmac any time soon.

Steve

[Ming]

Lovely looking bike, Steve. As for the front brakes, if I recall correctly the brake lines connect at the rear (ie next to the forks).

[EVguru]

The factory twin disc setup used a manifold block mounted from the underside of the bottom yoke.
This also provided a convenient place for the hydraulic brake light switch.

[Greybeard]

Thanks, chaps.
Re the brake pipes - I wondered if that might be the case - either that or a single line to one caliper and a rigid 'jumper' pipe across to the other side, under the mudguard, as per the earlier twin-disc BMWs like my R100RT. The braided pipes that were fitted have been made long enough to both reach the m/cylinder and connect with long bolt through a pair of banjos. Not the most elegant solution and certainly leaves no space to fit a hydraulic switch. I have re-routed the pipes this afternoon and it looks better, but I shall look at fitting a set as you both describe in due course. Seems a shame to ditch what are obviously fairly new pipes but it would make things a lot neater.

Steve

[EVguru]

Individual lines is the 'race' setup. It's how my '77 Sport was converted to twin disc many years ago by a previous owner.

There's space to fit a mechanical switch to the mastercylinder, 250 twins were fitted with the switch.