LAVERDA JOTA
Ralph finishes off sorting this lovely triple with some work on the chain.
You’ll recall that in the workshop I had spent a seemingly never ending time tapping the edges of the primary cover to persuade it off with glancing blows from a nylon hammer. It finally bent to my will and came away. The main reason it’s so awkward to come off is that it has housed in it some needle roller outrigger bearings for the end of the crankshaft and the clutch-shaft. When removing covers of this nature that always hold some oil unable to escape through the drain plug, I use oil spill mats that stop the bike bench turning into an oily skating rink, plastering my tools in slippery engine blood. Once removed it is clear that the primary drive chain does need to be replaced. Laverda states that they should be changed regularly, every 15,000 miles. Knowing which chain to use though is something of a nest of vipers, with various opinions from different suppliers. Originally they were a straightforward triplex chain. In 1984 Laverda then changed to a pair of simplex chains. I have talked to Keith Nairn of Laverda Scozia, and it is his contention that one shouldn’t use triplex primary chains as there are none available in this size of sufficient quality and he has seen plenty of triplex chains where the split rollers have disintegrated leaving lots of bits of roller in the bottom of the engine. He now recommends a duplex chain from a four wheeled vehicle diesel engine. I have to state that I see Keith as a bit of a Laverda guru and as an engineer he does speak the same language as I do. I am guessing that he wasn’t about when I replaced Patrick’s chain, as we fitted a DID Triplex chain that would have been sourced from another Laverda supplier, but at this point, I can’t for the life of me remember which one. It’s now some time on from this particular job and Pat’s bike is still running fine, with no rattles, but I have warned him to keep an eye on it. I next took away the tensioner gear by sliding it off the spigot and carefully removed all vestiges of the large gasket. The chain has to be slid off with both sprockets, but, before this can happen there is a large nut to be removed, securing the front sprocket to the crankshaft. While there is in existence somewhere a special factory tool to lock the primary drive up solid, it is suggested in the ‘Green Book’ that a piece of fairly heavy gauge mild steel bar 3in (75mm) x 1½in (38mm) can be used to lock the front and rear sprockets together. I had a look in my scrap bin and found a suitable piece of material. Having locked it up, I used a ½in drive socket with a big breaker bar, not forgetting to flatten off the tabs on the locking washer first. These nuts do tend to be as tight as a duck’s botty and had it been any tighter I should probably have resorted to my favourite air-gun. The rear sprocket has a circlip and shim washer that must be removed prior to removal.
The rear sprocket and bizarre ‘back to front’ clutch drum is slid off as one unit together with the chain and front sprocket. When removing the clutch drum it is important to take a note of the various shim washers that are employed to set the position of the sprockets. Once off I could feel quite a lot of movement between the sprocket and the clutch drum, indicating that the cushrubbers were cream crackered. The cush rubbers are found behind a round plate on the face of the sprocket. On the earlier bikes these were riveted on and the rivets need to be drilled out. On this one there were eight M6 bolts which I undid to reveal the eight rather fecked cushrubbers. New ones are available from good Laverda suppliers. When renewing the primary chain, it is good practice to replace all the needle roller bearings as well. I started with the bearing inside the clutch drum. I had made up a special tool years ago for fitting the same size bearing on Kawasakis.
It is just a bit of aluminium bar that I turned down in the lathe to just under the outside diameter of the bearing and then a further step at the inside diameter and further drilled and threaded it for some M12 studding. I used this tool to pull the old bearing out and then fitted a new bearing to it, passed its stud though the centre hole from the inside of the hub and then used a piece of milling machine tooling and a nut to draw the interference fit bearing into place. I find ratchet spanners are great for pulling bearings in – see photo. I next placed the rear sprocket over the clutch drum and fed the cush-rubbers in one at a time, being careful to fit them the correct way round, as they are asymmetric. I then refitted the cover plate, replaced all the spring washers with new and torqued the set screws to 8lb-ft. The next task was to check the sprockets alignment. The sprockets were replaced on their shafts without the chain and an engineer’s ground straight edge was used to check that they were perfectly inline. As you can see in the closer shot of the front sprocket, there is a gap which can be measured with a feeler gauge. There are various shims inside and out of the clutch drum which dictate its position on the shaft. After a bit of swapping around I got perfect alignment. There were signs of wear on the needle rollers installed in the chain case, so I removed them with a blind bearing puller set. Refitting needle rollers into blind holes is less easy than it was with the clutch drum. I used the same tool I used before, but rather than using it to pull the bearing in I had to use the tool to drift the bearings in a with a nylon hammer. In an ideal world one would gently heat up the chain case in the kitchen oven and freeze the bearing to make it an easier fit, but SWMBO was in the day this job had to be done and the rolling pin she was armed with told me to find an alternative heat source. I gently warmed the casing with my electric heat gun, which was much harder work than the oven, but did the job and didn’t provoke domestic violence. Before drifting in the bearing, I ensured that I had a nice soft towel under the casing to protect the vulnerable polished aluminium finish of the outside. The most difficult part is ensuring that the bearing goes in true and parallel; if you try beating it in on the piss, expensive damage will be the result.
Before refitting the front sprocket securing nut, it is of paramount importance that the tab washer is fitted the right way round. I refitted my bit of scrap, the other way around this time, to lock up the primary again so that I could retighten the crankshaft nut. For belt and braces I popped a bit of thread lock and seal in the nut’s threads. Once I had torqued up the nut, I re-locked the tab washer to ensure there was less than no chance of this nut coming loose. I use a small engineer’s chisel to start the tab bending process and then use a suitable pin punch to fully form the tab against the nut’s flats. The last job inside the primary was to refit the tensioner to its spigot. I then gave the engine case mating surface and its opposite number on the cover, a coat of Wellseal Jointing compound, allowed it to flash off for 10 minutes, before fitting the gasket and then replacing the cover. As always I torqued down all the cap screws with my trusty Laser ¼in drive digital torque wrench. I reassembled the curious mountain of new copper washers, adjuster lock nut and dome nut on the chain tensioner. I then filled the engine with some semi-synthetic 20-50 oil and warmed it up. The method of tensioning the primary is one of the strangest I have come across. Laverda’s ‘Green Book’ tells you to remove the dome nut, get an assistant to rev the bike at around 2000-3000 revs, slacken off the lock nut and then gently tighten the adjuster with a flat bladed screwdriver until you hear a medium pitched whine, at which point you slacken it back off until the noise just ceases. Once this odd practice is complete the lock nut is re-tightened and the washers and Dome nut refitted. The only task remaining was to test ride this glorious piece of Italian exotica and part my good friend Patrick from some beer tokens. Until it comes in for something else, that’s it for the Italian Stallion.