Gettin' back to the EVO. On the TC's, I have performed some of the upgrades to the breather system that is suppose to help blow-by......otherwise known as puking oil out the breather and the TC can be just as bad as some EVO's. One of those tricks was to enlarge the drain-back hole.

I have an EVO apart that was not known for puking, but I am wondering if anybody recommends any mods while I have it apart. I am a little behind the curve on EVO's....been over 15-years since I saw the internals on one. The umbrella valves still feel pliable and look good. I guess my question would be...."should I fix it if it doesn't need fixing"?

 

Nothing should need fixing unless it's broken, as you said. You could drop a couple dollars and just replace the umbrella seals.

The best thing I've found for getting rid of the oil puking in to the air cleaner is to route the breathers to a hose and filter instead of in to the air cleaner and running the oil towards the lower end of the dipstick.

 

This one was not puking, so I'll take your advice. I have found that the worst puking seems to be found on bikes with modified air breathers and filters. I think the stock breather systems allow that mist to be better sucked back into the engine, which is what it was designed to do anyway. I know we all want to get more air down the intake, but there seems to be a trade off. Once you disturb the air flow and mist coming from the heads....it has no place to go but out behind the filter. Most of us know that the modified breathers generally route the mist to a fitting on the rear of the backing plate below the intake. As air flows through the filter at riding speed, it tends to disturb the flow and blow this mist about inside the filter as well, eventually soaking the filter and blowing back on your shoes.

Too bad we still don't have chain-drive's. (No I really don't mean that.) The metric guys route the puke over to the chain. Self-lubricating I suppose.