Sell the bike for $4000 pay off your loan and buy a $2000 bike (probably find another F2) and get to work making it look good so you can sell it next year for $4000 and then get your F4i (with the split seat cause it looks stupid with the banana seat) and not have to worry about a loan at all.

 

I'd sell it and get a newer one, especially if he's gonna pay that much for it.

 

I'd sell it and take what you've learned and apply it to your next ride. Any time you can make a buck or even break even on a bike is a good thing.