OK - I've read through the posts here and I was wondering one thing...Are there any negative effects to the motor (or anything else) by re-routing the head breather to a filter or atmosphere?

Someone mentioned the vacuum system created by the air intake...wouldn't you lose the vacuum to the breather by re-routing? Could/Will this cause problems with anything?

I get a fair amount of blow-back in my 2004 Road King Custom. It has a Stage 1 and no other motor modifications. I've ridden about 150 miles this year (in the last few weeks). I removed the air filter tonight and it already has a nice oil coating all over the inside. Last year a clogged oil pump caused about 2 quarts of oil to eject out of my air cleaner. I've had the blow-back both before and after this happened. Either way, I'm sick of cleaning the damn air filter every other time I fill up with gas. This is getting ridiculous. The funny thing is, I never seem to use oil between changes. ???

Any help is appreciated. Thanks!

 

Now, *this* is the shiz:

http://www.accmachtech.com/catchcans.asp

No lame filters. Use a catch can that you can mount cleanly, and drain when needed. Available in clear (so you can polish) or for me the choice would be black.

UltraK, considering your penchant for cleanliness, I simply cannot be-LIEVE you just vented to atmosphere right behind the air cleaner. Messy messy. You'll see.

 

http://shop.ebay.com/?_from=R40&_trk...All-Categories

See above for a lot better pricing on a "can"....

 

 

If you have a motor that doesn't "bleed" serious amounts of oil from the breathers you're best to let it vent to the air cleaner. By serious I mean enough oil that the filter needs cleaning every oil change. My Evo will foul the filter and drip oil on the timing cover (and all the way back to the tail light while riding) so I used the same set-up years ago to end the mess. The only issue with venting to atmosphere is the spot of oil you'll leave every time you park your bike (plus, nearly everyone will point it out to you). A catch tank would solve that issue, though.

 

I had a 99 ultra that had a blowby problem. I had to clean the air filter after every ride. I replaced the stock breathers with Doherty breathers in the rocker boxes and it completely solved the problem. I kept the bike another year and 16k miles and had no blowby at all.

 

Golan makes a nice mini billet oil catch can for use on HD's

 

There is a lot of things the oil can mess with. It all depends how much oil gets into the Throttle Body but even a small amount is not good.

Stepper motor bikes have an issue with the oil/mist gumming up the stepper motor so when you come to a stop light the closed loop part of idle will take longer as the stepper motor plunger is dragging with oil residue. The bike will idle too low and you think it is going to die before the idle settles into the correct RPM point. I have to clean these all the time for correct operation.

All bikes have an IAT(Intake air temp) sensor hanging in the TB, when this gets coated up with oil the accuracy of this sensor is in question. This sensor is very important for proper Delphi operation. Intake air temperature has an enormous effect on igntion timing. There is a big difference between 50F air and 105F air in terms of ignition timing.

All bikes have a MAP(manifold air pressure) sensor. This sensor can also be affected by oil/mist. Since on a Delphi bike this sensor is critical for proper operation I would not want it to be effected in anyway.

Generally Oil/mist will gum up the top of the intake valves as well as could start to form carbon on the top of the pistons. Carbon on the top of pistons over time will effect the "squishband" of the motor setup which will ulitimately effect the ignition timing. This will ulitimately lead to detonation or pinging. I have (4) examples of this with customer bikes where I tuned them and they rode them for a time and they all of a sudden started to ping a little. We cleaned the bike TB vigorously with SeaFoam to remove some of the carbon and the bike went from slight detonation back to no detonation. One of the bikes was 1.5 years later and one of the others was 6 months so there is no real time limit. It totally depends on the amount of oil being sucked into the motor.

There is another school of thought that the oil/mist vapor will also effect the burn rate of the gasoline as it builds up in the throttle body. This means the bike performance will be affected over time.

My general procedure on the dyno these days is to clean the air filters, clean out the throttle bodies, change plugs, make sure the exhaust is tight at the head before I even load the bike on the dyno. One or all of these things will effect the data I collect when tuning a bike. I strongly recommend to all of my customers that they consider getting the head breathers vented to atmosphere. I have seen new bikes(2009) with under 5000 miles that had oil residue all over the TB and oil in the filters.

I have never owned a bike that I did not vent the breathers to atmosphere and I have not see any ill effects from this. It is nice to take the air cleaner off and see a clean like new TB. You be the judge!

 

Do all air cleaner systems vent into the throttle body? Is there any that don't?

 

JCleary - That can is 2.5" x 5.75"! It's like a water bottle with the top cut off - Where do you mount that on your bike?