2000mod jumping out of 5thgear

I have been doing a few track days and my vfr jumps out of gear at around 11700rpm in 5th.It doesn,t do it everytime but it jumps back to 4th unless you hold upward pressure on the gear lever.This occurs with the throttle pinned, so the gear is loaded.I,ve had the detent spring retensioned and this seemed to help for a while but it is playing up again.Does anyone do a shift kit for the bike that anyone knows of? Thanks.

 

Here you go...

http://store.azmusa.com/facproshifki3.html

8) RIDE WELL 8)
HWORTH

 

Thanks I,ll try the kit out and provide feedback.Everytime i think i,ve reached the bikes potential, i try something new, and the bike laps faster.Ground clearance currently limits mid corner lean angle, hence speed at the moment.I would like to test what scrapes next before I put expensive rearsets on ,if the extra ground clearance gives me at least a second improvement I,d consider it.

 

I found the answer.Chain tension.Even with 25-30mm sag(total) the chain tension changes alot from being on or off the bike.To set the chain tension at about 35mm of play off the bike reduces to about 25mm when seated.
This problem would get worse when 2 up so take heed.