Lately, I've been noticing an odor coming from the exhaust when the engine is first started. Goes away after a few minutes. Anyone ever notice the same thing? I use the same fuel in the 400 as the 450 and do not notice the smell in the 450.

 

you are prob smelling the exhaust lol j/p...um the mixture is prob too rich which is causing the smell check what gas you are supposed to use and use that instead

 

You experiencing any oil consumption????

 

Negative on the oil consumption. Happens only when first starting from cold. Run the same 92-93 Octane gas in all machines - just simpler that way. Runs good just stinks when warming up.

I must say too, when it is cold it seems to take a long time to idle on it's own. You can go to half choke almost right away, but when dropping down to no choke many times it will stall and "kick" back. After it's warm, no problems. I'll change the plug and see if that helps. Engine is still completely stock, save for adjusting the valves about a year ago.

 

400ex's are some of the worst machines to run in the cold months. Very cold blooded. i have to put a tarp over mine with a space heater blowing on it in the middle of janurary for it to start. also try using a lighter weight oil for winter, IE 5w-30, thats waht the honda dealer told me to run, and it seems fine.

 

Is the smell from the inside or outside of the pipe. Maybe its from your cleaning products...like over spray from wd 40 or the armourall got on the pipes. I know some of those products really stink while they burn off.