Question on clunky shifts

I bought a used 2010 VFR from a Yamaha dealer last year. Had 5K on it at the time. It really seemed to shift quite well in all gears, very smooth with hardly any jerk or 'clunk', even when shifting from neutral to 1st. I rode it about 500 miles then I changed the oil to the factory recommended 10-30W synthetic. It seemed like the shifting now is much looser, and shifting from neutral to first I now get a very pronounced 'clunk/jerk'...most of the time. I called the Yamaha dealer and they told me that they service every used bike using 20-50W oil before putting up for sale (probably not synthetic either). So my question is can I go ahead and try using a 20-50W oil again (summer time) non-synthetic and see if the bike shifts as it did when I bought it? Or will I mess something up by doing that. I did ride it with the 20-50W oil for about 5 weeks when I bought it and there did not seem to be any adverse affects. Thanks for any replies.

 

You haven't mentioned if it is a VFR800 or VFR1200, if VFR800 Gen 6 with only 5K on it you probably should use Motorcycle Specific 10-40W Semi-Synth eg Motul 5100,then switch to Motorcycle only full Synth 10/40w eg Motul 7100 if you wish after about 15K miles....

 

I switched to Rotella 15W-40 T6 Synthetic this spring & it's made a HUGE difference in shifting with my 5th Gen.

 

I might be wrong but I bet these bikes have straight cut gears and not helical cut gears. Anyone know? Straight cut gears while strong are never as smooth of a shift as a helical cut gear.

 

I ve used Spectro oils just for that reason about shifting. I just change out the Mobil 1 Turbo Diesel oil (800 miles) in my BB (OP used) because of shifting problems. It's shifting a lot better now. Golden Spectro synthetic-petrolium mix 10w 40. The only oil my 83 Interceptor worked the best on for engine noise and shifting for 65k miles. I've tried several different types of oils and have always come back to Spectro. It really makes the trans shift better. Just my experience.