Originally Posted by Mr B
What kind of gas are you using, if your thermo is mis-set or not working properly, you will get the knocking sound due to the fuel vapor igniting early. If the octane is too low that might be a contributing factor. I would have them check your thermostatic valve, i ride in 100 degree heat all the time and I never see my temp indicator bars increase, and my fan comes on too, occasionally at slow speeks.
Just some ideas!
Thanks for your answer B, but thats not a fuel issue as I had 102 octane racing fuel in it. I put that in as I had 5 gallons left from my racebike (which I sold).
However, the temperature did not increase dramatically, just one bar. Normally it is exactly in th emiddle of the indicator and that time it was just one bar above. But far from beeing even close to the limit.
Concerning the oil, well I worked for a company distributing oil and I even importet racing oils, so I know a bit about it. I wonder why an engine should be less noisier using a 15/40 instead of a 10/40. The "10" or "15" indicates the cold viscosity meaning both oils are as thin or thick at 100° C. No difference there...
That is why I will go for a 10/60 as I use in my supermoto and enduro bikes. The figure behind the slash indicates the viscosity at hig oil temperatures, normally at 100°C. So a 60 is thicker when hot than a 40. And this you can definitely hear on some engines when hot.
Thank you all!