i just read in another post https://cbrforum.com/m_201362/tm.htmhere to use seafoam to clean up the carbon build up? it kinda makes sense cause before this problem, i rarely rode the bike, maybe 6x in one year only.

think its worth a try?

 

As far as sparkplugs. I wouldnt put anything but the NGK's your bike had. I"ve ran champions with horrible results in the past. I've found the NGK's to be a very good plug. And no, dont run the wrong plug type in your bike. It will not run correctly. The higher compression of these engines needs a good plug to run correctly.

go to autozone for the plugs. they are far cheaper there. I think 9 bucks a plug compared to 15 at the dealership.

If you do have gas in the oil, change it. gas will degrade the oil and it wont protect your vital bearings.

 

You guys speculating that it could be this and that when the most obvious solution is FPR should quit. He already said it was leaking back which means the FPR is bad. The intelligent thing to do would be to change the FPR which you know is faulty, change the oil as a precaution, change the plugs cuz there probably fouled. Then if theres still an issue look elsewhere.