Re: What did you do to or for or with your Laverda today?

Didn't do anything with my bikes today, but brother Tim limped into my place on his 3C which was only running on 2 cylinders. Left one not working. He thought it was an ignition problem, but I had my doubts. With the right cylinder firing OK it could really only be a dodgy spark plug or shorted-our HT lead. Both were confirmed to be OK.

A little bit of investigation revealed the problem to be carby related (as many ignition problems are  ;)). The little cable that lifts the slide in the left carb had snapped. I cannibalised a set of old Dells I had on the shelf to get another cable. But when trying to balance the carbs, the adjustment was out of range. I got the balance good enough to get him home but will have to sort it properly later. Do those little cables come as a matched set?  If so, maybe if I replace the other two in his carbs with the ones from the spare set of carbs it'll improve matters.
 
It's possible to get these cables in different lengths.
I think ones for 36mm carbs (or bigger) are longer.
Found this once with a bike that didn't run right.
 
The new cable appeared to be about 1mm longer than the old one, but it was a little hard to tell accurately because the old one was frayed and broken. We got the balance pretty close but not perfect, with that carb right at the end of its adjustment. The bike is OK to ride (actually better balanced than it was before). We're going for a ride tomorrow morning, so might get a chance to look at it afterwards.
 
Cam this might help as a reference, from the Eurocarb website

Product Description

nternal cable to suit Dell?orto PHF carburettors with side lever operation.



For reference :-

There are 2 types of internal cable, and one fixed length non -flexible rod.

p/n 8831 Cable ? 73mm long
p/n 8951 Cable ? 76mm long
p/n 11003 Rod ? non flexible
 
Moved at least a ton of spares out to a safer location.
Amazed by what I have.
As soon as a house is found, all this is going to be catalogued.

Found a brand new cam cover, cam end covers and rev counter drive to put on the to be rebuilt SFC.
Still lacking original magnesium oil filler and a pair of 36mm PHBs.

Paul
 
My racer project that has taken me the better part of 2016 to put together is coming to an end.  Engine fired for the first time in decades, last week.  Only required a shifter fork and a set of valves to get it back to usable condition.  Sounds healthy, no knocks or clatters.  Running gear required a lot of attention, fairing was basically scrap.  The original tank had gone missing, so a new one was made.  I spent 3 weeks making a pattern, a friend in Belgium produced the finished item within 2 weeks.  Original Scarab brakes have been replaced with NOS Fontana magnesium components.  Rear shocks currently fitted are YSS, but only because time was running out.  Something more period will be eventually sourced, either early Stradas or up-market Ceriani GP.

Hoping to do a couple of shakedown runs on the dyno next week, before boxing it up for the trip to Oz.

http://s56.photobucket.com/user/sfcpiet/media/1973%20Laverda%20750SFC/DSCN7555.jpg.html?sort=3&o=0

Hope the links to the pics work.

piet
 
sfcpiet said:
My racer project that has taken me the better part of 2016 to put together is coming to an end.  Engine fired for the first time in decades, last week.  Only required a shifter fork and a set of valves to get it back to usable condition.  Sounds healthy, no knocks or clatters.  Running gear required a lot of attention, fairing was basically scrap.  The original tank had gone missing, so a new one was made.  I spent 3 weeks making a pattern, a friend in Belgium produced the finished item within 2 weeks.  Original Scarab brakes have been replaced with NOS Fontana magnesium components.  Rear shocks currently fitted are YSS, but only because time was running out.  Something more period will be eventually sourced, either early Stradas or up-market Ceriani GP.

Hoping to do a couple of shakedown runs on the dyno next week, before boxing it up for the trip to Oz.

http://s56.photobucket.com/user/sfcpiet/media/1973%20Laverda%20750SFC/DSCN7555.jpg.html?sort=3&o=0

Hope the links to the pics work.

piet
Click to expand...

Looking good, Piet!  8)  A lot of work goes into a project like that.  Any tricks in the motor that you want to share with us?
 
Rob,

Seems it was one of the original 73 engines with special heads and cams.  This actual engine is pictured in the Isles/v.d.Schalk SFC Registry book.  The magnesium cases have been replaced by aluminium items, cast to the same pattern, ie, larger rear mounting bosses, holes for primary chain adjuster and neutral switch not drilled.  No bosses for generator mounts either.  This engine had an old Dansi magneto fitted, I've swapped it for a modern PVL/Selettra type, similar to those used on speedway motors.  The head is a bit of a puzzle.  No longer the narrow-angle 73 type, it seems to be a prototype Elettronica type with alloy bathtub combustion chamber and berylium-bronze valve seats.  The barrel has spigots that go in recesses in the head, the "normal" Elettronica head is flat and the barrels have no spigots.  All valves were bent, I found the valve pockets in the pistons were not in line with the valves!  Looks very much like the pistons (cast Mondials) were one-offs, manually machined. The valves clouted the edges of the pockets.  I re-worked the pistons slightly to give the desired clearance.  Single row timing chain driving 6/C cams.  Also with 12mm cylinder studs.  Duplex primary chain running on slipper guides, no tensioner.  Close ratio "CC" gearbox, lightened selector drum and shaft.  Magnesium outer cases, including the sprocket cover!  PHB carbs needed a handful of brass and new gaskets after going through the ultra-sonic for 3 hours.  Engine weighs in at 64kg.

The frame is about 1/3 the weight of an original, box section swingarm with eccentric chain adjuster (nicely made, but a real pita to assemble!).  Fork is Ceriani GP in Laverda roadster yokes, pushing engine weight forward.  Front axle>crank distance is 3cm less than stock SFC.  Swingarm is 3cm longer.  Original brakes were Scarab all around, but everybody knows how reliable they are!  Swapped for NOS Fontana stuff.  Needed to make a new rear caliper hanger, revised the design a bit, a lot neater now.  Different clip-ons either side, battered exhaust system and general neglect were the minor niggles that needed attention.  Fontana magnesium hubs with magnesium disc carriers, new Morad rims (original Borranis were lost).  Total weight is..... 150(!!) kg, with oil and 5 litres fuel. :D

Bodywork was a real mess, fairing holed and fractured, mudguard missing, tank damaged beyond repair, seat cracked.  Made a pattern for the tank and had a new one made, pieced the fairing together and clagged it all up to be quite presentable.  A new screen and fresh paint has transformed everything.

I hope to do a shakedown run on a dyno next week, mainly to dial in the jetting and ignition timing. Engine sounds real sweet, with a very low vibe level.  Must be one of the smoothest SFCs I've come across.

Boxing it up and off to Oz in a couple of weeks, looking forward to displaying it at Eastern Creek.

More pics on FB, Moto Laverda.

piet
 
Dellortoman said:
But it's not orange
Click to expand...

Very fucking deliberately NOT!

The bike came in red livery with period stickers, so it could safely be assumed it was campaigned in red.  I intend to keep it as close to original as possible.

piet
 
Rob said:
Wow - will be a heap of fun to 'display' !  Those geometry changes should be a good addition to the mix too ;)
Click to expand...

To say I was excited as we put it on the scales this afternoon would be an understatement.  I was totally awestruck, couldn't really believe it.  Even if the scales are off by a bit, it's still a very, very light machine.  Glaringly obvious when pushing it around.

I'd post some detail pics, if I could work out how that works from a hosting site (I'm simply too dumb for that sort of stuff!).  Files are too large and turn out crappy when reduced to <200kB.

piet
 
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