As far as synthetic oils go.. I've been running Mobil-1 in my rig because I've heard it's pretty much the best of the synthetics... would Mobil-1 15-40 work well in 400ex too? Or would you recommend a different synthetic?

 

I have followed the synthetic oil theories and posts with a great deal of interest. On the various newsgroups involving motorcycles, the vast majority of riders in the USA and England are running Mobil 1. You can check it out for yourself by going to Deja News or Remarq.com.

 

I am running Mobil 1 15w50 right now in my 400, I like it so far...

 

so my 2004 trx400ex only blows blue smoke on idle and going really slow idk what to do no power loss and no white smoke only blue so dont think it is the rings maby somthing els plzz helpp