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Second in an occasional series of items retelling events down the workshop.
Jobs at The Workshop seem to go in "spates". There's always people doing things like balancing carbs but other jobs like fork seals, chain and sprockets, brake rebuilds, etc, seem to follow a trend with a bunch of guys doing similar things week-to-week. Last year we had a spate of rear suspension linkage servicing. Most of these went smoothly but there were two which were nightmares. The first was a VF400 which seized solid, I think this started the spate as everyone worried about their own machines. This was just a slow a laborious job involving a *large* hammer and a 10-ton press. The real frightener was a GL650 SilverWing. This machine was very tidy. It had recently been bought by one of our regulars from a guy that had it "dealer serviced" but did "all his own polishing"; you know the type. It came with a folder of receipts and ran cleanly, had 85k on the clock but was going into semi-retirement since it was planned to be a "sunny-day bike" and we don't get too many of those in the UK. It was only because the new owner had been around when the VF400 was being worked-on that he thought "I'll check that on my bike, sometime". A few weeks, and even fewer miles, later he came down, with his young son on the back. With the bike on a lift (hydraulic workbench) he offered up a spanner to check the size of the bottom linkage bolt. With the effort to slide the spanner onto the dirty bolt head, the head came away! After closer inspection we found that the rear linkage bush had seized in the housing. On the VF this had caused the suspension to become rigid but the GL was not to be beaten. Since there was no movement between the bush and the housing, the linkage had taken to pivoting on the bolt. The bearing area had moved from the length of bush (about 4") to the thickness of the frame plate that holds the bolt a both ends (2x eighth"). The bolt, which started at 12mm diameter, had worn through until there was less than 1mm, such that light spanner pressure was sufficient to snap it flush. The other end of the bolt was at about 2mm. The preload of the rear spring is such that no movement was detectable. Some monoshock rear ends give free movement at full extension if the linkage is worn. The repair job was similar to the VF from this point but the scary thing was that this was not found as a result of a detected problem. In fact the last receipt from the dealer included "servicing rear suspension linkage" as a ticked item on the checklist, and the bike had passed an MOT test only weeks before. This problem must have existed, undetected, for many hundreds of miles. If the bolt had failed on the road the consequences could have been fatal. Total rear suspension collapse would cause loss of control on any bike but with a shaft-drive this could also give transmission lock-up as the working angle of the UJ is exceeded. Both rider and pillion would have been passengers on a 500lb toboggan! Apart from the obvious message for owners of GL650's (and GL500's) to check their rear linkages, there's a widen conclusion to be drawn here. Don't be taken in by bright chrome and shiny paintwork. Dealer service checklists aren't to be trusted (how many times have we proved that?) and an honest, but ignorant, previous owner is no help either. It's not always used machines with dubious history that can fall foul (that's "foul" not "fowl" -DWP) of these "creeping problems". We often diagnose problems down to a component that the owner insists he "only just replaced". Turns out that "only just" was three-four years and thousands of miles ago, we all have memories that play tricks on us. When did you last change the fork oil or brake fluid? Really???? Return to home page