Laverda 1200 barrel

S

Shields

New member
Location
UK
Has anyone tried 1000 barrels on a 1200 bottom end?
Does it work?
I would like to try it but been told that there is a good chance of base gasket oil leaks.
 
Paul Marx said:
Just bore the barrels out and slip 1200 liners in.

Paul
Click to expand...
I have 1200 liners with pistons which have too high a comp for a road bike.
A Laverda expert rebored the bike and, without my knowing, fitted 750 pistons and had to machine the top edges off the pistons to miss the head gasket.
The result has been 3 batteries, a starter motor rebuild and continually rebuilding the starter clutch.
Total waste of time and money.
For a bike which is slower than before the rebore.
I also have a good set of low comp 1000 pistons and barrels - so if this conversion worked it would make a good reliable road bike, without further expense, which is all I want!
 
Shields said:
I have 1200 liners with pistons which have too high a comp for a road bike.
A Laverda expert rebored the bike and, without my knowing, fitted 750 pistons and had to machine the top edges off the pistons to miss the head gasket.
The result has been 3 batteries, a starter motor rebuild and continually rebuilding the starter clutch.
Total waste of time and money.
For a bike which is slower than before the rebore.
I also have a good set of low comp 1000 pistons and barrels - so if this conversion worked it would make a good reliable road bike, without further expense, which is all I want!
Click to expand...
In any case like that it is essential to measure the comb. chamber and find out exactly what compression ratio it has. It is vital for determining ignition advance etc. did they set squish, check all the other clearances?
 
Shields said:
I have 1200 liners with pistons which have too high a comp for a road bike.
A Laverda expert rebored the bike and, without my knowing, fitted 750 pistons and had to machine the top edges off the pistons to miss the head gasket.
The result has been 3 batteries, a starter motor rebuild and continually rebuilding the starter clutch.
Total waste of time and money.
For a bike which is slower than before the rebore.
I also have a good set of low comp 1000 pistons and barrels - so if this conversion worked it would make a good reliable road bike, without further expense, which is all I want!
Click to expand...
Sounds clever...:unsure: :rolleyes:

Once came across a 750 fitted with what looked like Yamaha XS650 pistons (never found out what exactly), crowns had been "re-worked" with a wood rasp to fit the combustion chambers!:oops:

piet
 
If you put the piston pin in each 1200 and 750 piston next to each other you’ll see just how radical the difference in deck and crown height is. As Tippie says buretting the chanber and doing an accurate calc of comp ratio is the only safe way of determining what’s what. That’s before you even consider swish to head clearance and piston to valve clearances.
 
Tippie said:
In any case like that it is essential to measure the comb. chamber and find out exactly what compression ratio it has. It is vital for determining ignition advance etc. did they set squish, check all the other clearances?
Click to expand...
No!
BTZ ignition has to run on full retard.
Another thread suggested 11.5 to 1 is normal with this setup.
 
Not sure what you mean by having to run on full retard - it may be set static that way but will have an advance curve for a running motor.

11.5:1 sounds way too high for a road motor running on pump fuel to me. I'd say 10.25-10.5 max.
 
sfcpiet said:
Sounds clever...:unsure: :rolleyes:

Once came across a 750 fitted with what looked like Yamaha XS650 pistons (never found out what exactly), crowns had been "re-worked" with a wood rasp to fit the combustion chambers!:oops:

piet
Click to expand...
Tell tale signs of a well known German bodger, hopefully not at large anymore......
 
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