Hello My ST4 has chrome flakes on the oil strainer and evidence of de-chromed rockers on the vertical inlet openers at the very least. Ive "um and arrd" about what to do but I think im going to go down the newman cams rocker and MBP retainer route and do the job properly and once. (Bike has only 12.4k milesand ive just spent a bit on servicing the forks, re-gasing the rear shock and new head bearings and new tyres... and all the service kit... etc etc etc..... so I'm going to stick with the old girl...) Question is... what damage do I risk doing if I continue to run the engine for a few hundred miles before undertaking the above work? Is there any chance that chrome flakes may get into bearings and cause premature wear, or that the de-chromed rockers could cause cam damage? At the moment the cams look to be in good nick. valve clearances are all within limits except one closer that's a bit tight, at 3 thou. The reason that I'm considering a short period of continued use is that I'm off to the black forrest on a family holiday in a few weeks, I had planed to trailer the bike over there and do a few hundred miles of early morning curvey skermishing. The above mods are not feasible in the time avilable so, whats the worst that can happen?? Ralph
Without seeing the wear in person it's hard to give advice, but seeing as I've been down this road with my old ST4, having noticed the wear, I would find it hard to risk wear on the cams too, which will be the result! IF the wear was minimal and there was still a layer of chrome on the rocker, then I MIGHT risk a couple of hundred miles. However, you pays your money and takes your choice! When I was having my engine rebuilt by Louigi Moto a few years ago, Rich had a huge box full of worn Desmoquattro rockers and horror stories of knackered cams . . . With regard to the Dave Newman Cams refurb, this is definitely the way to go for a permanent fix. Just do the rockers in pairs or you may get some slight vibration issues due to the everso slightly different profile. Done in pairs I didn't experience the problem though. Given the money I would have done the lot in one go, as at the following service I had to do two more! No wear at all on the DNC ones though.
I don't think anyone can guarantee that the loose chrome flakes won't end up somewhere that could cause damage but as far as running with slightly worn openers, I'm sure you will be fine. The stellited replacement rockers from Newman are a good alternative to standard, there are a couple of people on here who have done high mileages on them with no problems.
This is the best way, do it once and never have the problem again. This is what Ducati should have done instead of denying there was a problem and sounding surprised that it had even happened when I contacted them - shame on you Ducati UK! Also MBP retainers are great, since doing mine I've hardly needed to change a valve clearance and nothing at all in the last few checks...
I suppose my line of thought is something like this. When flaking occurs your not aware of it as it happens and only discover it by chrome on the strainer or at some point later if you're unlucky, by symptoms of serious valve train wear. You could change the oil then almost immediately have the chrome flake then do a full service interval of ignorant bliss before you'd know... if you did big mileage between services. With this being such a common problem and people often needing the odd new rocker at a service, it seems unlikely that is does more serious harm in the short term. If this were not the case and rocker flaking was quickly followed by e.g. chrome in bearing bearing failure or rapid cam wear we would have had an even bigger fiasco during the time these quatrodesmo engines were regularly flaking out? Any guys out there with engine building experience have a view on this? Clearly in an ideal world I'd stop right now, but I really want to do this riding in the Black Forest and I will be trailering it out there if the worst happens and the engine packs up for whatever reason...
Let me do the honours and scare you.......maybe I was riding along happily on my 748sps when suddenly there was a sound like loose gravel rattling in the belly pan it shuddered and went on to one cylinder. I Was half a mile from home. I took the belt covers off and the vertical cylinder belt was shredded Anyhow I left it for a long time (fitted a 916sp in it) Wandering about the garage one day decided to take the head off aNd see the damage. I was gobsmacked there was none. Valves perfect not a mark on the piston The point is though the inlet camshaft bearing was sized. It was stuck solid. I kept working at it and suddenly it freed up. I can only think a piece of chrome was stuck in it. I had serviced it new oil 700 miles previously but I didn't find chrome in it then. There was when I dropped the oil the second time
