i usually end up throwing stuff. when i tried to take my tires off by hand with tire irons (big big big mistake) i ended up throwing the tire iron and it bounced and hit the roof of the shed which is like 15 feet in the air. i solved my problems and set them against a big wood suport beam in the shed and set the forks of the fork lift right above the bead very carefully and pushed it off the bead. lol billy style

 

Well I'll help where I can I'm not real up on the 400's but there are plenty here who are and will help. Don't give up I have been there before it sucks I know.
It sounds like you don't have a air leak unless it's a crank seal. What do you think about maybe having a bad jet?

Jeff

 

I feel for you RAJ. I've been having trouble with mine for about 6-8 months now. Not anything like your prob. but still little stuff that will make you contimplate the "gas and zippo" cure. Let us know what it is when you find out.

 

Get yourself a B8ES plug then do a plug check again.

 

When you popped the cylinder on did you use a new base gasket? Did you use any kind of sealant on the gasket? Did you have the bottom end apart at all? Are you sure you torqued the base nuts properly? Have you double checked the torque on the head gasket? Do the compression check and make sure you are not to high or low. If you are high you will need to run higher octane fuel if you are low then you have an upper leak somewhere. Try the new plug maybe your current one is just burning to hot. Are you having any problems setting the idle? Does it tend to race on you at idle or have a nice controllable idle speed? Somethings to look at also if you could answer the questions it might help with some more ideas to check. Jay