View Full Version : Rattling in engine

11-08-2005, 07:37 PM
Okay guys try this one:

Bike started making a knocking noise in the engine, it is not heard at start up but slightest revs and it can be heard. At high revs it goes away again. The bike recently had a top-end done. The aprilia mechanic reckons it is most likely the big end bearing or the main bearings. Does anyone recognise this and know if the mechanic is correct? or should i try something else first (I will be doing the work myself).


11-08-2005, 07:48 PM
A rattling noise from an engine can be many many many different things.

Why did you have the top end replaced?

If it was because of lubrication failure then your bearings may well be shot. But unless you're certain don't let them do a crankcase overhaul, as you're looking at a lot of money. The bearings don't go for no reason, and the top end will go before the main/big end bearings (ie if it seizes it's usually okay, but if a professional mechanic replaces the top end they'll check the bearings by yanking the con rod, if there's any play they'll let you know they need replacing, unless they're cretins)

If you're competant to do a top end then you should be able to find the fault, the obvious thing to do is run over the engine making sure every bold is tight.