On any bike with a couple thousand miles, it's pretty easy to see how that oily sticky residue builds up inside the throttle body. This same residue is on the inake valves and on the pistons (because modern oils don't burn well). Blow-by must be dealt with. The EPA says it can't be vented to atmosphere, so the re-burn is about the only option. The tradeoff is this residue. A separator or catch can is the ideal option. So yeah, they've been doing it for years, so you can trust the engineers is a one side. Smack those fools because the engineers couldn't get a oil pump right. The residue isn't good for the engine, but it isn't an engine killer either. Call it a necessary evil. Can't believe people are still arguing about this....

 

This is a factory stock Twincam. The head is right off the jug. I forget exactly how many miles but it was around 70,000 and never apart till now. scary isn't it, Thats why some folks still argue about this. Tell you what though, I have run external myself in the past on an engine that liked to puke out of the breather, It ran an S&S cleaner that did a bad job in regards to the breathers, it just dribbled down and soaked the filter and puked on the cam cover.. My current M8 has no issues like that so im riding off into the sunset. To each his own. Good Times!

 

 

Gunslinger, this inlet photo looks remarkably good,really not at all frightening,especially after 70000 Miles!

 

I was talking about the butterfly valve mainly. The intake valves at least get a little cleaning being downstream of the injectors.

 

For some reason my pic would not upload last night, but this is the piston off of my 18 RGS with 1000 miles...


bypass vent tube is just above cleaner cover.

 

Hey, you got a free performance upgrade after 1000 miles. The more carbon added to the top of the pistons= more compression. Just one of the benefits of owning a new Harley.

 

 

The oem air holes in the breather are roughly 1/8" ID. No restrictions in the new lines I ran. These are going flowing into a 3/8" fuel line which are double the size of the tiny OEM hoses on the OEM cleaner. Also if you start the engine you will notice that there are serious engine pulses pushing air through the line. I've ran 4 bikes like this and never had a problem.

And yes I pulled the heads for a 117 kit. Why wait? And these pistons are like this DUE to the way the factory jets that crap right back in the engine.

 

Here's a video showing a kit that some guy bought from dark customs. The kit is basically what I did...and it works.