Q. I get an unusual rattle for a few seconds when I first start my BMW R1200RT from cold.
It comes on after about 15 to 20 seconds of starting, lasts about five seconds, them disappears. Any ideas what it could be?
Anthony Wilcox, email
A. Our man Andy Downes ran an RT as his long-term test bike this year, and he concurs that his was a “bit noisy” immediately on start-up, but that it quietened down quickly.
Even so, it sounds like they have the same cause and that’s a timing chain tensioner rattle. The oil can drain away when parked, causing a rattle until the pressure gets up to the heads.
Your engine oil should be Castrol 20w-50 or Castrol Power 1 10w-50 if you want a full synthetic.
Naturally, check the valve clearances and the rocker shaft end float as these can also make noises. Noises are a bit louder as it is an air-cooled engine.
If you know someone with a stethoscope (stick end not a doctor’s one!) then you can put it against the tensioner retaining cap and you will clearly hear if that is the cause. Workshop stethoscopes are about £20 and can save a fortune in misdiagnosis.