My 900cc Sci has a strange habit of sounding like a sewing machine on start up, not every time, maybe 30% of the time.

I can't think of another way to describe it, almost like very poorly adjusted rockers maybe? It does this for a while, anything from a few seconds to a minute or two and then it stops.

Any ideas???

I have the same on my 900 cinq im puzzled aswell

Reminds me of my Barchetta when the timing belt tensioner was worn out.

Probably the tappets need adjusting ( but noise will return after so long) or the oil simply needs changing - the oil replacement and adjustment are just short term fixes though as its a permanent trait of the 900cc engine - most owners just leave them and get used to it

The noise goes away due to the oil warming up the tappets as the engine warms up

The Sei 900 won't have any adjustment on the rockers, they are a pure hydraulic setup (all be it one that doesn't work too well!!).
The adjustment on the 900 rockers went towards the end on the Cinq 900. So late Cinq 900 and all Sei 900 have no adjustment.

The only cure (if a simple oil change doesn't help) is new hydraulic tappets, or conversion to the non-hydraulic setup from a Panda.

I went for the non-hydraulic setup.

:yeahthat:

I went for the 'diesel flush' option which worked really well and has cured the problem 90% of the time. Still noisy on first start up on colder mornings but generally much better.

Vagra said:

I went for the 'diesel flush' option which worked really well and has cured the problem 90% of the time. Still noisy on first start up on colder mornings but generally much better.

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Brave man!
Worth doing a few oil changes to make sure all the Diesel is out of the system.

As for the oil to use, I first ran it on Castrol Magnetec 15W40, soon changed to Magnatec 10W40, then Halfords own brand 10W40 Semi, then settled on Mobil Super 2000 10W40.

The Mobil feels the best of all of them.
The Castrol Magnetec 10W40 used to need topping up the most often.

Using Diesel is no different from flushing oil which you don't seem to see as much of now, they are both very thin oils effectively.

Worth noting that Diesel comes out the drain plug a whole lot faster than oil, thank god I was prepared!