Good day everyone, I hope you are all safe and well. Yesterday I test rode a friends latest addition to his paddock, a '64 plate 675R with ~16k miles on the clock. Previous week we did a full fluid service including coolant, spark plugs, filters and also brakes and brake fluid change. Yesterday, riding in 3rd gear I opened the throttle and got a moment of high revs, no acceleration and then the transmission kicked in. I asked my friend about this and he said it was like that when he bought it and thought it was normal behaviour. I've never experienced this on my bike a '14 675R. His intention is to primarily use this bike as a track-bike and it would be great to hear some advice on this issue and how we might go about diagnosing the root-cause. Your responses are greatly appreciated. Thank you.
Fwiw I don't recall ever having heard anything like this before. Don't know about you, but my initial suspicion would fall on the semi slipper clutch?
Thanks for the reply, I was a bit confuzzled too! Any advice on diagnosis for the clutch? Will it need taking apart and inspecting do you think? Thanks
I'm afraid I personally have had no experience (yet) with the new semi-slipper type clutch. My assumption was based purely from deduction of the symptom you described. Thinking on,,,,, Which particular engine oil did you fill her with.? (or what oil had been in there previously) The reason I ask is that it has been known for owners to use a premium car engine oil of the same viscosity grade, not realising that some additives contained in order to reduce engine wear can cause clutch slipping issues (car clutches are not oil bathed, unlike our motorcycle ones).
I would check the clutch free play at the lever first, should be 2-3mm at the pivot end of the lever, also the clutch lever pivot itself, make sure the brass bush isn't seized and its greased properly. Had clutch slip on my Thruxton because of the lever. It could be the clutch itself but I measured my friction plates at 22k and they were only worn 0.04mm out of a possible 0.1mm, to wear out at 16k it would have had to be seriously abused.
Thank you, I will pass this information on and focus in on the clutch and surrounding mechanics, starting with lever pivot and moving towards the more expensive issues if it is not the lever.
We changed the oil and and have no idea whether it was bike specific; although it has a full service history and was changed by dealer. We've used the Castrol 4T Racing one to replace what was in there. The extracted oil had a red tinge to it, so suspect (maybe incorrectly) that it was the right oil. Further investigation needed and I found out yesterday that the bike is still under warranty but would need a ~400 mile round trip to The Smoke from Yorkshire. Thank you for your help and advice