Barrel

Quite obviously the cylinder barrel cannot be removed from the engine without first removing the cylinder head! Once the head is off, however, barrel removal is very simple.

If the barrel is not already loose then you can carefully tap it with a hide-headed hammer. Never lever it off. Carefully pull it straight up the studs. It's quite likely that the barrel gasket will come away too. Make sure the camchain ends are pulled through and laid over the crankcase. Once the barrel is off, stuff the crankcase with clean rag to stop anything else falling in there. Rest the pistons and rods on rag on the crankcase. On the Triple, when you have removed the studs because you are leaving the engine in the frame, make sure you lift the barrel up 'out' of the crankcase. It doesn't just sit flush on the crankcase. On the Triple, from 1000 number 2483, you will find a small O-ring sitting in the crankcase underneath the barrel gasket in the front left hand corner. This was fitted to stop oil leaks at that spot. Pick out the O-ring and make sure you replace it with a new one when you come to re-assemble the engine. For engines prior to this fitment, it makes good sense to have that O-ring seat milled into the crankcase half but only if the engine is totally disassembled.

Fortunately the Laverda barrels for both the Twin and Triple have removable cast iron liners fitted. This means that the barrels can go on being reconditioned indefinitely although two oversizes of piston are available before replacement needs to take place. Liner removal and refitment is NOT something you can do — you must have it done by a very experienced and fully equipped engineering shop. The same goes for the reboring of the liners for the fitment of over-size pistons.

(The standard Twin and SFC liners are not the same).

Once the barrel is off the engine inspect each liner carefully. Clean the whole thing first. Check first for scratching and scoring and then check for wear of the sort which you should expect. A ridge will manifest itself a few millimetres below the top edge of the liner, at a TDC position. To check whether wear is great enough to require a rebore, place an appropriate piston, without its rings, into the bore and measure the gap between the piston and the liner wall at the bottom of the piston, with a feeler blade.

Check the specifications for the penmtiec amount of gap and then take the measurement at several points around the bore to check for ovalitv. (Only the cylinder can be truely cylindrical). An internal micrometer, if you can obtain one. will give a superbly accurate picture.

Always rebore in each bore of the barrel unless the engine is very new and something else has gone wrong.

Seek advice from your engineering shop as to how the bores should be rebored and honed. Even brand new liners require honing.

NOTE: If the liners are chipped at their lower edge you may be able to get away with it depending on how big that chip is. Liners cannot be repaired, only replaced. The allow casting of the barrel fins can be repaired if they are broken. It s usually cheaper than obtaining a new barrel.

Refitment of the barrel is quite straightforward on both types of machine although, of course, piston ring compressors MUST be used for safety Base gaskets can only be fitted one way around. Lightly grease both sides of the gasket. Don : forget to squeeze that round O-ring into the oval hole in the lower crankcase half on late Triples. Q cooler engines require a different base gasket to those otherwise fitted. Gasket cement should not be necessary. A good trick is to fit the barrel down the pistons with each piston resting on two blocks of wood so that they remain 'upright' as the barrel is fitted, to then rest on a bigger piece of wood placed between the barrel and crankcase so that you can then look both ends of the oamchain through. Use lots of clean oil down the barrels so that the rings will slide as easily as poss ible and don't force anything. Obviously you should have checked that the rings are placed in the proper position. See the next sub-section. Turn the crankshaft to check freedom of movement for the pistons and rings.

Support the cylinder head on a piece of wood onto the Lowering the head down with the camchain ends studs before... collected (Twin)

NOTE: In the centre of the Twin's barrel you should have refitted the anti-vibration camchain wheel. Make sure it's there and that the wheel's spindle is well oiled, that its two thrust washers are fitted and that the whole thing is properly fixed. In the front half of the Triple's barrel, in the camchain tunnel, is the anti-vibration blade for the chain's front travel. It is clipped in top and bottom and needs to be replaced before the barrel is fitted. Make sure it is always in place.

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