New start for Al’s bottom end
Crank needs a regrind and new big end shells, rest of it seems in reasonably good health
Last month saw me in a slough of some despond at the realisation my 900SS’S big-ends were in an amount of trouble. There was a glimmer of hope, however, in the thought that it had simply spun a shell and that if the crank had survived unscuffed I might get away with new plain bearings.
Having initially thought I couldn’t get the conrods off with the cases still intact, further inspection and a tad more determination showed that I could. I attacked the rod for the vertical cylinder first, as this was the one that had gone stiff on the crank. As it came apart it was quickly obvious that the lead lining of the shells had mostly departed. I slid the rod for the horizontal pot along the crankpin to where the other one had been and it moved freely enough suggesting that at least the crank hadn’t been knocked out of round.
At this point all hope of an easy fix evaporated as when I ran a tentative fingernail along the crank pin it picked up just ever so slightly. Nearly got away with it but not quite. Regrind time. Removing the other rod revealed its big-end shells to be just as devoid of white metal as the other ones. Replacements are in quarter and half a millimetre oversizes however they’re typically more than twice the price of standard ones at around £60 each. Can’t say I fancied a £250 bill just for those, plus the crank grind too. A late night trawl of ebay turned up three 0.25 at 39 Euros each at an Italian dealer and one with a UK seller at £30. That was a bit more like it. Figuring that the Italian fellow would struggle to find a buyer for an odd number like three I made him an offer he immediately accepted. There was no such option with the UK vendor but I was happy to pay his asking price to net me a set for just around the ton. That was more like it. I ordered up some new conrod bolts from German firm Stein-dinse for 9.81 Euros each.
While that lot was in the post, I turned my attentions to stripping down the rest of the engine. The first problem was that having been so confident at the outset of this debacle that all I was doing was fitting my homebrewed big-bore 944cc top-end, I hadn’t even bothered to drop the oil. There was 35 quids worth of fully-synthetic in there and it had only done about 60 miles. There’s a fair amount of heft in a Ducati bottom-end so I dismissed the
I WASN’T WHOLLY OPTIMISTIC On ABOUT the left old rod THE and crankpin – scrap. On the PULLER’S CHANCES OF right, the fresh stuff SUCCESS BASED ON PAST EXPERIENCE BUT IT HAD THE PRIMARY GEAR OFF IN SECONDS. I WENT TO EBAY AND BOUGHT ONE
idea of holding it over a bowl while the lube trickled out. I managed to siphon most of the oil out. Although once the engine’s side covers were off it soon became evident that I hadn’t been wholly successful in this endeavour. A massive slick spread across the bench when I leaned the engine a little to one side to extract the starter motor. There commenced a cleanup operation of epic proportion. By now I had wasted way more than the price of new oil in time and effort expended. Lesson learnt? Maybe.
It’s a few years since I rebuilt the engine but it was all surprisingly familiar. I remembered that the primary gear – which is mounted on a taper on the end of the crank – was particularly tricky to extract. Last time I took it to my local Ducati specialist, St Neots Motorcycles and they used a hydraulic puller to remove it. Quite often these gears are so tenaciously attached to their cranks that the mechanics have to wind up the puller and just leave it on there until the cog decides to let go, usually with a dramatic bang as it leaves the shaft and clatters to the bench. I had no such puller to hand and even a trawl through Pete O’dell of The Motorcycle Works comprehensive tool chests failed to unearth anything suited to the task. However one of our neighbours is RM Clutch Services and their line of work requires all manner of pullers and extractors. Proprietor Richard offered me a loan of his Snap-on CJ86-1 twoleg puller. I wasn’t wholly optimistic about its chances of success based on past experience but it had the primary gear off in seconds. So impressed was I that I went straight to ebay and bought a used one from the States. The really clever feature of this particular puller is that the legs can be braced together to stop them bending and popping out from the gear as pressure is applied to the centre screw.
From there the rest of the engine strip was a slam dunk. As you might predict the oil strainer had captured some evidence of the big-end shells’ demise although some bits of stray grey gasket goo made things look even worse than they were.
Every oilway will need blowing out prior to reassembly and the oil pump will be coming in for particular attention. For now I’m off to get the crank ground. I’ll let you know how that all went next month. Will 0.25mm shells be enough or should I have gone 0.50mm. I can hardly stand the anticipation.
Smiling through adversity as ever (until he gets the bill for the crank regrind)
Valves and guides all checked out OK. A relief
Snap-on puller – brace to prevent legs splaying
Acid etch primer: £14 a tin. But you’ll want it
After a bit of gentle persuasion and industrial language
Good for nothing now
White metal. Yuck.