LAVERDA 1200 cylinder block

From memory, a 1200 Laverda was actually 1115cc. The factory obviously wanted to make it sound really big and brutal. Why, I don't know, because they were quite a sweet, sedate motor.
 
The power of the press, decades back, all the local mags, especially Two Wheels who tested 1200 Laverda Triples, said they vibrated more than the 1000, so when it was suggested I go 1200 when my engine was rebuilt, I declined. Since then, everyone who has gone 1200 I ask, and they say toque increase, but vibs do not. So don't believe everything you read. I did at one time go to max overbore with a 1000cc barrel but that was a whole nother nightmare that ended badly.
 
Very few actual 1200cc triples out there Vince. Most end up 1145 using 81mm pistons. going any bigger creates clearance issues, liners get too thin therefore having to bore out the cylinder block to take larger liners. Can't say what the maximum bore on standard liners are.
My opinion the 1200 motors are way better than 1000. Way more torque and with high comp and hot cams will eat a jota any day.
No noticeable vibration with the extra cubes either. Rode a jota the other day with 36mm dels and my bike would leave it in the dust.
Road testers know fuck all and write for the sake of writing.
 
motoddrob said:
Very few actual 1200cc triples out there Vince. Most end up 1145 using 81mm pistons. going any bigger creates clearance issues, liners get too thin therefore having to bore out the cylinder block to take larger liners. Can't say what the maximum bore on standard liners are.
My opinion the 1200 motors are way better than 1000. Way more torque and with high comp and hot cams will eat a jota any day.
No noticeable vibration with the extra cubes either. Rode a jota the other day with 36mm dels and my bike would leave it in the dust.
Road testers know fuck all and write for the sake of writing.
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Hi Rob, I can confirm that!
My white 1200 SC comes with 82,5 mm pistons after an engine overhaul - I think that's the absolute maximum. Some tried even 83 mm but this led to engine damage because the head gasket becomes too narrow in the area of the studs.
Ciao, Gert
 
So Gert what your saying is 82.5 is pretty much reliable Max then
1186, still not quite 1200
That would leave a wall liner thickness of 1.75mm
1201cc @ 83mm, 1.5 wall thickness
Im happy with my 1145. Goes like fuck!
 
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Red had some oddball 1000cc very oversize Hi Comp pistons we tried, approx 5kms into its first test ride, one liner broke and slipped down and hit the crank, launching Will over the bars at maybe 30 or 40kph. Took some skin off and tweaked his shoulder. We were lucky; it knocked the crank out of phase and scraped up the front guard and remote front brake master. Still got those battle scars on the bike. So another trip to Queensland for repairs and another lesson learned. It's only money, right? God knows how long ago that was, the bike has done thousands of hard ks since then. It's so much fun riding a bike with that much punch.
 
motoddrob said:
So Gert what your saying is 82.5 is pretty much reliable Max then
1186, still not quite 1200
That would leave a wall liner thickness of 1.75mm
1201cc @ 83mm, 1.5 wall thickness
Im happy with my 1145. Goes like fuck!
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It doesn't even manage that Rob. There's a relief of 0.5mm just under the liner flange where 86mm od becomes 85mm.
So a standard liner overbored to 82.5mm would be 1.25mm at thinnest point and 83mm would be 1.0mm

I'm fairly certain that Gerts 1200 must have the cylinder block overbored to fit oversize liners.

I'm an advocate for 81mm max 1144cc on "std liners", it works. Cc = direct horsepower but I know how expensive custom made liners are, then overboring cylinders. Approx 1hp per 10cc at laverda tuning level, 100bhp per litre. So around 4bhp and 4nm torque increase like for like. All good but it costs to do it right.

Rob
 

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Vince said:
Red had some oddball 1000cc very oversize Hi Comp pistons we tried
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not how I remember it Vince, you asked for 78mm pistons on your 1000 triple which have 82mm OD Liners which I did, they were Ross Racing Pistons, they were not "oddball" pistons
your Liner broke straight underneath the Flange where the Liner is wasted slightly so wall thickness is less than 2mm in that area
Since your engine broke I have refused to bore 1000 Liners out to 78mm, my maximum size I will consider going to now is 77mm

A 1200 Liner has an OD of 86mm, I will not go past 81.5mm on those Liners for the same reason

On my race bikes I use custom made 89mm OD Liners made by LA Sleeves in USA to retain wall thickness

When you look at how a 1200 engine unmasks the Combustion chamber the whole design of the 1200 engine and concept makes way more sense than a 1000 engine which has part of its Combustion chamber shrouded
To me a 1200 engine is the correct design but fuck, I'm only a Drilling Engineer and a Fitter and Turner so what the fuck would I know
 
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