Yep, I tend to lean towards your diagnosis, a valve or tight lash

I hhave a habbit of doing things right but this weekend on a moonlight project, 2006 xr650l, It started hard and when it ran, would smoke like nuts. I knew everything was right but something didn't seem right. Listening to the top end with a stethescope there was no normal valve clearance noise. After rechecking the valves, I had both intakes tight. hmmm. Not satisfied I pulled the head, disassembled and checked everything. Intake springs were soft. Seems they would give a littla as I was clearancing the valves. Not saying this is your problem but something to check.
Other than that, If a ring chattered out during the initial start-up. I would also look at the lands and grooves on the piston.

----- Gimpster -----

 

I would definetly check the head for either a bad valve or one being too tight.

 

EVERYBODY THANK YOU SO MUCH... I HAVE NOT FOUND MY PROB. BUT ON ON A MUCH BETTER PATH!! THE ENGINE IS JUS SO CLEAN ON THE INSIDE, AND THE RINGS, PISTON, AND PISTON WALLS ALL LOOK GOOD...NO, GREAT!!

I CAN SEE WEAR IN THE RINGS THOUGH. THERE NOT AS WIDE AS THEY WERE WHEN I PUT THEM IN. AND AS FAR AS VALVES, THERE ALL NEW. THE SEALS, SEATS, AND KEEPERS ARE ALL NEW.

ALLTHOUGH I DID BUY A HEAD ON EBAY THAT HAS A LOT OF HELI-COILS IN IT!!! WHICH MEANS ITS HAS BEEN TIGHTENED AND LOOSEND A LOT!! I MIGHT HAVE TO GET A SHOP TO DO A TEST ON IT. I DONT KNOW HOW TO MAKE A GHETTO LEAK DOWN TESTER!! IF SOME ONE WANTS TO TEACH ME IM ALL EARS.

THANKS FORUM GUYZ!!

 

Ok, I have about 5 ninutes to explain this because have to go to work.
Take an old plug and put it in a vice. Bust the insulator off with a hammer.
Take a center punch and start chipping the insulator out of the center of the plug. This will take forever because that stuff is hard.
After this is done you should just have the base of the plug that is hollow.
Take the base and braze a 1/8" short pipe nipple on it. Then take an air fitting and screw it in the nipple.
You now have a getto leak down tester
Screw it in your head and bring the engine up to TDC. Set your air compressor (you do have one of those don't you?) to 100PSI and inject air into your engine.
Listen for where the air comes out. Breather- bad rings. Air box = bad intake valve.............ya yada yada..............got to go...I'm late..............

 

GOTCHA!!! YES...I HAVE A CORN PRESSER.LOL...THANKS AGAIN!!

 

Just a little tip oon the spark plug porcelin insulator removal. If you break the top off the plug, take it to the grinder on tha hex wrench end. Grind it down and as you get cluse to the hex part, there is a retaining ring inside. Grrind it far enough to get the ring out and the porcelin will easily fall out or can be tapped to fall out. This should save you some chipping time when building a cylinder pressure up device

----- Gimpster -----

 

YOU GUYS MAKE IT SOUND SO EASY. THANKS AGAIN!!!!