tonk Posted September 16, 2012 Report Share Posted September 16, 2012 Had a bit of an 'incident' recently (see crashers thread) and the rocker cover got knocked off in the collision. This was on my HP2 Sport with a boxer flat twin engine (giant sticky-out pots). I shut the throttle straightaway and stopped asap from 50mph and switched off. The bike was recovered to a dealer and then inspected by the insurance engineer. Without looking any further, the engineer wrote the bike of as a total loss on the basis that the snapped cam chain would have caused internal damage, necessitating a new engine - the dealer said they wouldn't split the engine, only order and fit a new one. Does this sound right though? The engineer only allowed the dealer 1.5 hours to examine the bike and provide an estimate. I'm told there was no damage to the piston by the valves. The rest of the bike was undamaged (to clarify, I was clipped by a car, head on, but didn't fall off so it was only the cylinder head and my leg that got fuckered). Are engines that fragile? Are engineers so clever that they can see inside crankcases without looking? I couldn't replace the bike and now someone, somewhere is going to make a fucking fortune raping it for parts. I can't do anything about it now because I've got the cheque and already bought a new bike. I'm just curious. Link to comment Share on other sites More sharing options...
Benji Posted September 16, 2012 Report Share Posted September 16, 2012 Quick look in the spark plug hole with a borescope readily available this days would let you see what the damage was. Compression test would give you a slight indication that there was valve damage. It's unfortunately how the insurance industry is, sell it for salvage, and beat the punter down on what their insured item is worth. Link to comment Share on other sites More sharing options...
tonk Posted September 16, 2012 Author Report Share Posted September 16, 2012 Cheers Benji, I'm assuming that as soon as the chain broke then the valves would have snapped shut on their springs, giving maximum clearance. Two of the four valves bent, again clear of the piston. That leaves the chain, supposedley flailing around inside the engine, but in reality within a narrow channel with another tensioner on the other cylinder head. Here's quick sketch I did... Link to comment Share on other sites More sharing options...
lorenzo Posted September 16, 2012 Report Share Posted September 16, 2012 The other thing to consider is that you've suddenly lost all power from one half of the engine, which might've thrown all sorts of stresses on the crank maybe? personally, I can't see how that'd write a bike off, but if it is, it'd be worth looking at buying it back I'd imagine. LIke's been said though, a boroscope and compression test will tell you an awful lot about things inside. For that matter, what's the issue with taking your head off yourself and having a look. If they're just writing it off, the head's damaged anyway, go for it. Link to comment Share on other sites More sharing options...
tootall Posted September 17, 2012 Report Share Posted September 17, 2012 The valves would only snap shut if there wasn't a cam lobe in the way at the time. In which case they'd be shut anyway! Link to comment Share on other sites More sharing options...
HeadtheBall Posted September 17, 2012 Report Share Posted September 17, 2012 I've seen several Ducati race engines where the cam belt/belts have let go and whilst there was no visible sign of damage as a result of piston/valve interface the concussive force of the minimal contact was enough to put flat spots on the big end bearings. On one engine where the owner refused mine, and others, advice that a bottom end rebuild was needed it failed two track day session later when the big end bearing picking up. Very much this. We can all moan like drains that insco's desire to write bikes off at the drop of a hat is a shame/makes insurance expensive/causes global warming/whatever, but you'd be pretty fucking sick if they just stuck a new chain and rocker cover on it and the engine grenaded 6 months later. Link to comment Share on other sites More sharing options...
tonk Posted September 17, 2012 Author Report Share Posted September 17, 2012 @lorenzo - I can't/couldn't do any inspection myself, I'm still immobile with a broken leg. It was written off on the Friday afternoon and collected the following Monday morning by the salvage yard before I'd had chance to organise gettting my hugger and tax etc off the bike. Talk about fast. That was also before we'd agreed on a price so technically it was still mine. There was no way to buy it back, the cost of parts is ridiculous with it being a race-derived engine (£12k for a new engine alone) and i just don't have the skill to rebuild it. @tootall, mille and header - I appreciate the info, that's the sort of stuff I would never consider. It just all happened so fast, felt like I'd had the rug pulled from under me. And then a few days later, a mate dropped his £6000 bike at 15mph on a bumpy track in spain and had that written off because of £7800 worth of damage. But thank you all, crash bungs are on the shopping list for my new bike Link to comment Share on other sites More sharing options...
Tomfoolery Posted September 17, 2012 Report Share Posted September 17, 2012 What's the new bike, Tonk? Link to comment Share on other sites More sharing options...
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