Ok guys I know its pretty hard to describe something online like this but here it goes. I am getting this weird rattle and, at first, it sounded like it was coming from the front end. It happened when i was riding, just a little hard, and all of a sudden i lose a significant amount of power and the rattle starts at around 3,500-7,500 until the engine is too loud to hear. So I started from the simplest solution and worked my way up. I first tried readjusting the CCT 3 times and it didnt work. I'm sure I adjusted it properly. Next thing I did was checked the spark plugs. Loos like im running a little rich but no biggie. Then i start to suspect a exhaust leak so i decided to pull of the headers and check the gaskets. One seemed a little out of wack but the rest were ok. So i decided to pack the gasket holes with RVT to see if that solved the problem. I'm still getting the same rattle. Now after listening more closely, it sounds like its coming from the rear now. The engine is so damn loud its freakishly hard to even find out where the rattle is coming from! I'm going to go to the shop tomorrow and see whats up but i though maybe a couple of you guys can chime in. Thanks for any advice. Video coming shortly

 

My buddy had a loose chain causing rattle and slapping about 4k rpm's. Look to see if there is any slack or play in the chain. It might be rattling or slapping the front cog on the way back if it is too loose or hitting the chain guard. Just trying to help.

 

Ill check on that. The chain actually does sound a little loud. Ill let you know how it goes.

 

Well it wasnt the chain. But the rattle is definitely coming from behind the drive sprocket. I looked at the manual and its not really detailed enough for me to pin point the problem. Loose pinion or something somewhere?

 

Came back from the shop. It doesnt look too well. It could be a lot of things from inside the block. Maybe a valve guide fell or the engine needs replacing. Either way, im going to have to either sell this bike for cheap and get a new one, get my hands dirty with what little time i have in my schedule, or pay for repairs which im sure would be worth more than the value of the bike itself. I'll try and find some solutions this weekend. Maybe open up the heads to see if something is loose. Thanks for the advice

 

Motors are cheap too get, unless to spec racing. Ebay motors go for $300 and up. I am haing a spec built. I do have a couple to choose from if you want. Starting at $250

 

^^^Thanks for the offer but if I was going to look for new engines I would look locally. Shipping would kill me. Lets hope this one is still usable though!

 

New motors is going to cost as much as spec($2500+) or more. Might as well get a new bike then. Try rebuilding it first then. There is a downloadable F2 manual somewhere on here.

 

Is it still running? I lost a valve keeper once which caused a valve to continually drop into the cylinder, then be pounded back up by the piston. Sounded exactly like you describe. You can isolate valvetrain problems because you probably won't have compression in one cylinder. Feel the headers and check that they're all evenly hot. If they're not, you probably only have some head work to do, which is cheap and easy and can be done at home.

 

It runs and i drove it to the shop twice. I was planning on taking the head off tomorrow because the valve keeper was my first object to look for. The compression is definitely off in one cylinder so it could be a loose part or timing. I didnt feel all headers individually, but my hand got burned feeling for an exhaust leak after a few seconds of being on. Im hoping just a loose part haha.