Folks, thanks for having me, while I’m new here, over my 64 years I’ve owned several BM’s, (R69S, R100RS x2, K100RT, K1100LT) and my current bike, K100RS SE ABS1, which I’ve owned for 10 years or so. I also own lots of other bikes (Triumph Rocket III, Harley Sportster x2, Ducati S2 x2, BSA C11, Kawasaki Z1-B, Mach III 500’s x2, KZ750 twin, Honda CB750 K0, Suzuki T500 and T350, Yamaha XS650 and DT250, etc etc.)
I pulled the K100RS out of storage after a 10 year nap recently and replaced the battery, fuel pump, ultrasonically cleaned the injectors and tested them, changed the oil and filter and coolant. It fired right up, so as I’ve kept the club registration and insurance up, yesterday I gave it a was and went for a ride.
The bike was running flawlessly and I’d ridden around 40 miles, when the oil light came on. I stopped on the side of the road and put it on the centre stand. With the engine running I could see that it had plenty of oil, and could see it moving around behind the sight glass, so assumed that the light was faulty as I’ve had a few weird electrical problems with this bike.
I continued riding for another 10 miles or so and as I pulled into a little town, was sure I could hear a faint knock. Bugger. I rang the auto club (RACV) and ordered a tow truck. When I got home I dropped the oil and let it drain overnight. This morning I dropped the new K&N oil filter. I measured the oil that came out, about 3.5 litres and it looked pretty clean, but when I tipped it into a container for disposal I saw some tiny golden flakes. No chunks, just tiny flakes the size of a pin head.
I installed a new BMW oil filter and tipped in 3 litres of new oil. Hit the starter button and the oil light went out, then flickered on and off. I can hear a faint knocking from the front of the crankcase, which sounds like rod knock. I’m now debating on whether to rebuild the engine or buy another one.
Any thoughts? I buy most parts from Motobins and they list new bearings, so I’m wondering if I’ll get away with replacing the main and crank bearings, and reconditioning the oil/water pump, or whether I’ll need to replace the crank and rods. I’ve built plenty of other bike engines over the years, but have never had a K100 engine apart. Any suggestions would be appreciated. Cheers, Terry.