Clutch & Gear issues

[pauLI]

Morning gents
After some advice/thoughts please
The clutch on my series 2 starts off relatively easy to pull the lever in to change gear but after about 15 minutes of town riding it gets stiffer and stiffer to the point it makes my wrist/forearm ache and it’s really difficult to pull in the lever. It’s a 4 plate with uprated springs.
Also occasionally when in 3rd at the top of the Rev range on the cusp of changing into 4th the bike jolts (like it’s jumped out of gear) could this be a result of the clutch issues or an actual gear box problem?
Final question
running a muggy 186, with a delly phbh 26mm carb, pacemaker gear box, bgm bigbore through a wide necked TV175 air box, am going to fit a bigger tank and go with a remote air filter, will i need to change the jetting at all?
cheers
Paul

[Hat]

clutch issue is caused as it heats up, closing the gaps between the plates & causing drag. can you adjust the cable out at all to compensate for this?

swapping from an air box to remote filter could affect jetting