I am the proud owner of 09 AC THUNDERCAT and have had no issues until today. We we're doing some top end runs on a paved road and after about the 3rd pass i could smell oil and there was steam coming of the engine. I looked and there was oil coming out of both air box drains. I took of the air box cover to discover there was alot of oil in there. This is the second time and only seems to do it with top end riding. Any ideas as to what is causing this problem?

 

oil overheated and foamed out crankcase breather into airbox.

 

After speaking to the mechanic I now know that running these bikes at full throttle will cause this sort of issue in the winter. He recommends dropping a half litre of oil for top end running. The crankcase builds too much pressure with oil being thicker than normal and has to go somewhere. He told me to also use thinner oil in winter or stop running WOT. )9 T-CAT.

 

thats it

 

I had this happen when the oil filter needs changing as well. Almost like the oil cannot flow through the filter fast enough and pressure builds up and the oil has to go someplace. I do not notice it when doing a lot of full throttle riding for a period of time following an oil change.

For a lot of people not running at WOT is not an option so a thinner oil in winter is probably the way to go. Are you running synthetic oil by chance?

SJ

 

I was running the AC oil which comes in the kit but changed to amsiol after this the other day and it has'nt happened yet. I also dropped a half litre and the problem hasn't come back so I think it worked.