Author Topic: Crankcase Breather (Read 12936 times)

ricklee4570 · « **on:** June 21, 2007, 06:51:22 AM »

I have been thinking about the Crankcase Ventilation. It goes into the Airbox. My thinking is that it surely cant be good to route engine gasses and oil mist back through the carbs into the engine. I have to drain my airbox of oil every so often. This tells me that more than likely oil is being sucked into the carbs. I know this is an EPA thing where we are trying to reduce emissions.

Wouldnt it make more sense to only introduce fresh clean air into the engine through the carbs. I think this would make more power, and keep the carbs cleaner.

Has anybody experimented with running a catch can and an inline filter on the end of the vent tube and just plugging the airbox inlet from the crankcase? My thinking is that this would still allow the engine to vent the gasses and the oil would be caught in the canister.

okbandit · « **Reply #1 on:** June 21, 2007, 08:43:52 AM »

I am running a stage 2 Holeshot setup where the airbox is completely eliminated. It forces you to deal with the crankcase vent in a seperate manner as you describe. Mine just has a filter on a piece of hose ziptied out of the way and works great. The part of your description that sounds like trouble is that mine does not leak any oil. From your description you have a problem of some sort if oil is collecting at that rapid a rate. If you do plug the line and use a filter or catch can with stock jetting it is likely to lean your mixture a bit, but if that happens it is easy to correct. You need to find out where that oil is coming from though, it sounds excessive.

ricklee4570 · « **Reply #2 on:** June 21, 2007, 08:52:45 AM »

It runs like a top, spark plugs look normal. I have put about 1700 miles on it, and just checked the plugs, all good. No smoke from the exhaust. I changed the oil and filter and put 3.6 to 3.7 quarts of oil in it, just like the manual states. When cold on centerstand it registers right at the halfway mark on the sightglass. When hot, right at the full line on centerstand.

So I dont think Im overfilling the oil. After about 1600 miles it wasnt appreciably low on oil. I drain the airbox about once a week and get a little oil out, enough to puddle in the palm of your hand. I do tend to run it in the higher rpm ranges occasionally (8000 to 9500 rpm) for short blasts on the highway. Bike now has 38,000 miles on it (mostly highway) Compression is good on all cylinders. Oil is definitly coming from crankcase vent.

I was assuming this was normal??

wedge98 · « **Reply #3 on:** June 21, 2007, 10:31:58 AM »

I had a very similar problem with my TL1000R. The problem was just that as the bike ages the air/oil mixture increases in volume and as a result the volume of the hoses used to remove the mixture becomes inadequete.

To fix this problem I adapted much larger fuel line hoses to replace the stock vent lines and ran a long (approx 3ft) line to a filter vent which replaced the 6 inch line to the airbox. This fixed my problem and I have been running 500 miles with no oil issues since this fix.

The bike has 10,000 miles on it, but I've done a lot of track time with her so the engine has more wear than a normal commute TL.

ricklee4570 · « **Reply #4 on:** June 21, 2007, 11:27:43 AM »

Quote from: "wedge98"

I had a very similar problem with my TL1000R. The problem was just that as the bike ages the air/oil mixture increases in volume and as a result the volume of the hoses used to remove the mixture becomes inadequete.

To fix this problem I adapted much larger fuel line hoses to replace the stock vent lines and ran a long (approx 3ft) line to a filter vent which replaced the 6 inch line to the airbox. This fixed my problem and I have been running 500 miles with no oil issues since this fix.

The bike has 10,000 miles on it, but I've done a lot of track time with her so the engine has more wear than a normal commute TL.

Im not sure I follow you on that? What difference does length of the vent line make? If oil is coming through it, it wouldnt seem to matter how long the hose is. It will just take a little longer to get to the end. Maybe Im just not understanding what you mean?

Red01 · « **Reply #5 on:** June 21, 2007, 03:53:11 PM »

In a healthy engine, the amount of oil mist inhaled thru the airbox almost nothing. The oil mist burns just fine with the rest of the fuel mixture. This keeps the environmentalists and the EPA happier than venting the oil mist overboard like they used to do. Having a catch can would work too, but then you have to empty it somewhere.

okbandit · « **Reply #6 on:** June 21, 2007, 05:51:56 PM »

I run the poo out of my 2001. I have racked up 15k on it and I don't have any oil mist to mention. I routinely run to redline. May just be the oil level. There are a lot of different methods to set the level even from factory suzuki sources. I would try running at the bottom of the sight glass for a week and see how much you collect just as a test. My vent as mentioned before is a filter from autozone ($10) and a piece of hose and it is ziptied under the tank so it is higher than the valve cover. Might be that any oil in my line is draining back into the motor when I park it. If your test comes back the same as with the current level it might be a solution for you as well.

bikeb4cage · « **Reply #7 on:** June 22, 2007, 09:09:07 AM »

I posted on this a couple months ago - I have a stage II (crank case vent filter) and DO get misting - bike has 10K miles on it - have played with the oil level, but still get the misting, regardless of how low I set (within reason...pretty sure if I drained the sump I would get no misting). I presume this is normal, but since I am the third owner, who knows what kind of abuse the bike has had. My bike doesn't seem to consume oil, but I haven't put more than 1000 miles on it since getting it, so hard to say (since I have been playing with oil level in that time frame). Will have a better feel for oil consumption in a couple weeks when I take a 3 day trip to Deal's Gap. Anybody know what could be causing excessive misting (other than oil level)?

thanks
Jay

ricklee4570 · « **Reply #8 on:** June 22, 2007, 09:41:23 AM »

I am beginning to think that the misting may be more common than most think. Mine has had the compression checked, and its very strong, and it mists. Under high rpm it will blow some oil as well. I think some bikes may be more prone to this. Most people that are not as enthusiastic at checking all the mechanical aspects of their machines would never notice the mist.

I am a little hesitant to keep reducing oil level to prevent it. I would rather run the proper level of oil than to run low.

wedge98 · « **Reply #9 on:** June 22, 2007, 01:01:37 PM »

Quote from: "ricklee4570"

Quote from: "wedge98"
I had a very similar problem with my TL1000R. The problem was just that as the bike ages the air/oil mixture increases in volume and as a result the volume of the hoses used to remove the mixture becomes inadequete.

To fix this problem I adapted much larger fuel line hoses to replace the stock vent lines and ran a long (approx 3ft) line to a filter vent which replaced the 6 inch line to the airbox. This fixed my problem and I have been running 500 miles with no oil issues since this fix.

The bike has 10,000 miles on it, but I've done a lot of track time with her so the engine has more wear than a normal commute TL.

Im not sure I follow you on that? What difference does length of the vent line make? If oil is coming through it, it wouldnt seem to matter how long the hose is. It will just take a little longer to get to the end. Maybe Im just not understanding what you mean?

Well there are two major differences here from the stock setup:

1) all hoses ID have been increased to the maximum size I can use

2) The length of the hose to the airbox is longer

The first difference is the biggest reason the fix works. What this does is increase the volume for the mixture to go through which drops the pressure and helps keep the pressure from pushing the mixture into the airbox.

the second difference is like adding a little extra room for error. The farther the mixture has to travel, the harder it becomes for it to reach the vent as oil. The idea is the oil gets stuck on the walls and the air passes through the middle. I've experimented a lot with this on my TL and the longer the hose, the better it works.

Now in theory there is a different hose length that will work for all bikes, some may need a few inches, others a lot more. It all depends on how bad your situation is.

I plan to do this mod on my new 1200S soon. I'll take pictures when I perform the modification and post them on my webpage so you can see what I do.

Best of luck :)

ricklee4570 · « **Reply #10 on:** June 22, 2007, 01:28:38 PM »

I would be interested in seeing the pics! Thanks!

roogazza · « **Reply #11 on:** June 26, 2007, 01:28:07 AM »

Though not noticable on the street, at race meetings and after a 6 lapper I seem to get a fair amount of fumes and mist . My motor is in pretty good knick with good compression so I'm not really concerned.
I have thought of fitting an extra vent when I remove the alternator (a plate blanks off the hole ) as they seem to have a lot of crankcase pressure. Gaz.

wedge98 · « **Reply #12 on:** June 26, 2007, 03:52:49 PM »

I took my 2002 B12 apart over the weekend to inspect the bike and do some work on her. When I took a look inside the airbox I saw a fair sized puddle of oil. So it looks like I suffer from this issue as well.

I plan on doing the hose mod in July or August when I also add the following:

Ivan's Jet Kit (carb sync and then tuning) $130 shipped
Jardine Slip-On Street Can $250 shipped
Pair Removal plates $42 or I might make my own

Oh and if you are looking for this, there is a hose with a plug in it that removes the oil from the airbox. You should unplug the hose and drain it.

okbandit · « **Reply #13 on:** June 26, 2007, 04:46:03 PM »

Wedge I have the pair plates for $10 if you need them. Had a mess laser cut.

wedge98 · « **Reply #14 on:** June 26, 2007, 11:39:41 PM »

Quote from: "okbandit"

Wedge I have the pair plates for $10 if you need them. Had a mess laser cut.

I'll take them! :D PM sent