Engines bigger than 1200cc

V

Vince

Hero member
Does anyone remember the story of a bloke in either Germany or Austria using car pistons to build big-bore Laverda Triples in the dim dark past? They didnt last long.
 
I think you refer to Claus Nieland. They were actually 750ccm Twin engine motorcycle pistons from a Yamaha. Don't get me started on that man, please...
 

Pistons for Laverda SF2 advice wanted

Hi all, I need a set of pistons for a SF2 engine and now I am checking what suits best. What I have and what is fixed for that engine: Standard motor with standard crank. Bore will be 82mm. 36mm carbs. Standard head or slightly modified head with C5/C6 like cams. It will be ambitiously used...
laverdaforum.com laverdaforum.com
 
In theory, it could be infinitely big.
  • Hilbert Space:
    Quantum mechanics uses Hilbert space to describe the possible states of a quantum system. This space is infinite-dimensional, meaning there are infinitely many possible states a quantum system can be in.
 
Franz(?) Laimböck from Austria claimed over 1300cc for the triple he envisaged. CAD drawings floated around the www, afaIk, nothing became of it.

82mm pistons were offered by Asso before they dismissed themselves from the aftermarket. 82mm dia. x 74mm stroke = 390.8cc/cylinder.
Still not the full 1200... :ROFLMAO:

piet
 
There was an advertise at Kleinanzeigen last week about an engine case and a barrel with 83 mm dia. I wondered which piston can be used and if it is possible for the threads in the engine case? But 83 mm would be exactly 1200 cc and not more.
 
… 82mm piston were used in every Sulzbacher 1200 S and 1200 SC - first Asso and then forged Mahle. Werner Sulzbacher announced the 1300 ccm Kit in a brochure from 1978, but it never came to the market. My own 1200 SC has now 82,5 mm forged Wahl pistons - this is the absolute limit. Ciao, Gert
 
Fuck it in for a penny, take care going to big. Years back, I had a sleeve come loose and hit the crank after using a very big piston. There isn't a lot I haven't broken over the years. Unexpected consequences can occur. That was in a 1000cc engine.
 
In Archive Stuff there is a piece on Simonato Pacifico ... ( Cico ) ..... which states he turns out 1203 cc triples ( 83 mm pistons at least I suppose )
........ weighing 330 lbs .........

As regards the 330 lbs .... It says ..... " Yes , you read that right .... " .......... Which is probably coded speak for " complete bollocks " ............

( I mention this in case someone jumps in saying things like ....... it`s completely impossible ....... never seen anything like it in 40 years ...... an engineering absurdity ....... etc. etc . etc ........ ) ................. Yes , I already know ............


Brecon Quaddy wrote the article , whilst visiting the factory to have a ride around the test track on the first production RGS ........ ( or maybe it was the prototype with the odd looking mirrors ) ...............

...... . but he`s dead now .......... ( think ) ........... :unsure: ..............
 
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Bigger than 82,5 isn't possible as the liner reaches already into the oil galleries and gets thin like alloy-foil.

82,5 with unchanged 74mm stroke = 1.1887ccm (r²*pi*stroke*3=ccm)
 
standard 1000 Liner OD is 82mm, number of engines worldwide are running with 78mm pistons in that configuration so wall thickness is 2mm, sort off but just below the flange the Liner has a small relief groove hence that reduces the Liner thickness at that point
Biggest pistons I will use on a standard 1000 Liner is 77mm

Standard 1200 Liner has an OD of 86mm so I limit the overbore to 81mm, which is 2.5mm wall thickness

On my race engines I use custom made Liners from LA Sleeves that have an OD of 89mm and my custom Ross Racing Pistons are 81.5mm giving me 1160cc, I reduce the Liner overhang to 86mm to fit to the Engine case bore
I designed the Liners to be the same as the reduced length Liners as used on the Series 2 and RGS

I could go to 84mm piston size which still gives me 2.5mm wall thickness and a capacity of 1230cc but the limiting factor is the available head gaskets
At 84mm Piston size the pistons bash the available head gaskets so I need to have custom made head gaskets which is really not an issue
Looked at that a number of years ago and asked Cometic to make me MLS head gaskets but they quoted US$3,500 for the design and tooling and would not give me exclusive rights to the gaskets so told them to shove it up their butt
However there are other companies around that will make custom head gaskets

It has taken me 7 years of racing my triples to figure out how to make them reliable at 1160cc, they are easily making 134hp rear wheel by running huge compression, expensive race fuel and nearly 100 hours on the Flowbench so has not been easy to keep them in one piece, gone through a lot of parts and numerous engine rebuilds in those last 7 years

Been a huge learning curve and very expensive to work it out but now that we have not damaged an engine for nearly 12 months after installing the Slipper Clutches I am thinking of having custom made head gaskets, 84mm Ross Racing Pistons and higher lift Camshafts designed and made

I already run PAC Alloy dual valve springs in the race engines and can go to 13mm Valve lift if I wish before going anywhere near coil bound
This racing caper trying to obtain big power from an old clunker at this level is very expensive

Have no idea how much the Horner Brothers have invested in building their all billet Vincent race bikes, far more then I have that is for sure but I don't have their resources either
At a wild guess racing my two Laverda race bikes over the last 7 years, it has cost me well over $170,000 which has resulted in a number of $40 trophies

Fuck it, is only our Daughters inheritance I am spending and I really do enjoy listening to a 180 Laverda race engine on full song
If it was a 120 I would have stopped 6.5 years ago
 
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redax5 said:
standard 1000 Liner OD is 82mm, quite a few engines running with 78mm pistons in that configuration so wall thickness is 2mm, sort off but just below the flange the Liner has a small relief groove hence that reduces the Liner thickness
Biggest pistons I will ues on a standard 1000
Click to expand...
My one day to be resuscitated 3C runs 78mm pistons in 1200 liners with the top case bored out.
Paul
 
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