just changed the oil for the first time in my 400 ex and it had a really strong gas smell to it. anyone had that same problem with theres if it is a problem.....i think it might be break in blow-by...what do you think??

 

I'm not sure of the EX carb....but I'm pretty sure you have a leaky needle valve assembly. I had that problem on my TM45 off my DS650.

The problem was, even when the float bowl was full of gas...the needle valve wouldn't seal the gas line closed....hence letting fuel fill up the carb and then come out of the main and pilot jets...Then...the fuel would flow down the carb throat and intake...and into the engine....Mixing in with the oil...

By the way, this is all when parked and not running....


I simply replaced a torn O-ring worth 30 cents around the needle valve assembly....and bang...no more richness, flooding, waste of gas or gas in my oil.


Hope this helps

Jeff

 

The explanation given sounds reasonable to me. I would turn your gas valve off after you ride too. I can only imagine the explosion should enough gas mix with the oil to allow it to ignite.

/Jon