Forum

[JOHNNY SINGLES]

Why on earth did they ever put a nylon gear in this engine to drive the oil pump? and did it need that extra flywheel on the end of the crankshaft for the alternator????
Is there many problems with these new engines as there are so many used ones of them on the market and the prices are going through the floor, even ones with very few miles on them.

[sofiaspin]

Who knows, cost cutting and poor engineering? Yes a second hand EFI is a damn good deal.

[Michael]

Just out of interest... have you any trouble with the oil pump?

[Presto]

A nylon oil pump gear is common on many modern engines: Honda, Kawasaki, Suzuki, Yamaha, Triumph - to name a few. (I don't know if they are any good though!) The 'flywheel' on the crankshaft is a rotor, that functions as an essential part of the electronic engine management system to control ignition timing and other functions.

[Midge]

Simplicity is the main reason I abandoned modern bikes and why I like my '99 500. A few years ago I had a Piaggio 500, lovely thing but riddled with problems. A common fault on them was the fuel injection to over-fuel causing petrol to mix with the oil in the sump dissolving the plastic oil pump gear which destroyed the engine. The last straw for me was when the immobiliser decided to randomly cut out the engine, luckily I wasn't overtaking at the time.

[Presto]

The advantages of plastic gears are (we are told) that they run without lubrication up to a certain speed, they reduce wear, maintenance and oil contamination; they are able to gain higher speeds, reduce noise, reduce gear vibration and shock, reduce weight and (possibly) costs. The material is stress-free, resistant to moisture absorption and corrosion, is dimensionally stable and light-weight. All of which may explain the advantages of plastic gears. But it also begs the question why are plastic gears used only for oil pumps (and/or water pumps).

[Michael]

That's why I asked about 'any problems with the oil pump gear'... just cos it is plastic doesn't mean it is rubbish or a design flaw, or poor engineering. Think of it this way, if the gear stripped then something must have caused it to strip. If the plastic has enough strength to be driven by the metal cam gears under norla operation with a little bit extra for a quality factor then it is sufficient.