my bike is the same way. It seems to pull ok in lower gears, but in 5th and 6th really runs out of steam. It's not a slipping clutch, its low compression and jet issue

 

idk i didnt see anything in the video. but i can try putting a jet kit in it after taxes and see if that helps.?????????????????????

 

You could, but be warned there's no magic in a jet kit. If your fuel mixture is on, it's on, and that's that. I'd pull a spark plug or four and see what they look like. It'll at least give you a ballpark on the fuel mixture across the board.

Do you have a pipe on your bike with no jet kit?

 

the plugs are brand new and yes i have a pipe and no jet kit

 

Jetting problems don't simply appear overnight. If it ran fine prior, then the issue is something else.

You're skipping steps here and it'll cost you. What's the bike's history?

 

Since you have a 12 bar on it, do you have a dinner plate as a rear sprocket? In other words is it geared for low end?

Try turning the choke on at the times this is happening to you. If it helps then there is not enough fuel. If it makes it worse then there is too much. You will need a jet kit. Really what you need are the adjustable needles that come with the kit. The jets in the kits are just a good starting place. The kit will probably tell you to install clip on groove 3 from the top of the needle. Install it on groove 4 from the top.

You can have good fuel mixture at idle & not enough fuel at WOT.

 

Again, A/F problems related to the bike's jetting cannot and do not appear overnight. Without the bike's history and diags, saying he needs a jet kit can (and prolly will) be a waste of money.

I had a flat spot that 3 carb cleanings, 1 fuel pump, 1 fuel filter, 4 new plugs and 1 jet kit didn't begin to touch. Following the manual's diagnostic flowchart might have saved untold hours of manpower and a couple hundred $$$s spent in the wrong direction (air solenoid stuck closed cause of speedo).

Starting at the beginning, did the bike always do this?

 

They do not start overnight but the F2 does not have a air solenoid of any kind. He has an exhaust system with no adjustment in fuel or air. It will NOT run correct wether it run good before or not. It can run better if he corrects it. We do need specifics on when & how it started.

 

He just said his bike was like that. I assumed his bike was always so. Did it just happen?

If you want to get more technical, fuel mixture can change. Not overnight, but rapidly. If the filter becomes obscenely clogged, it will be rich. If you develop exhaust leaks, then it will lean out. If you have bad gas or the gas gets nasty in there, all sorts of fun can result. Cracked carb/engine heat couplers, or loose fitment? Lean on the cylinder in question. Loose vacuum take-off or poorly clamped or cracked vacuum cap? Lean. These are all examples of how one's fuel mixture could quickly change "all by itself." They are obvious causes with predictable effects, but may go unnoticed by the untrained and make the bike behave mysteriously.

 

The solenoid was an example of how I wasted a lot of time and money.

Putting a jet kit in on top of an underlying issue will skew everything, including how the jet kit should be installed. A slipon isn't a drastic enough change to the AF that it should cause a flat spot. Too many people toss new cans on their bikes without rejetting them already. And its still unknown if the exhaust is a new addition or not.

Without fixing the underlying problem, new additions can add more problems that need to be fixed. And will definitely add more variables to solving the overall problems