Crankcase breather

[Jitsguy78]

Can someone show where the Crankcase breather is? Thankyou.

 

[dmonkey]

On the right side of the bike the breather tube connects to the crankcase right behind the starter motor, it bends and passes to the left side of the bike where it feeds into the airbox.

 

[Jitsguy78]

On the right side of the bike the breather tube connects to the crankcase right behind the starter motor, it bends and passes to the left side of the bike where it feeds into the airbox.
View attachment 2854

Thankyou

 

[Thepen]

Does anyone know if there's a one way valve in that system? Or is it just a regular straight tube? Thinking of just running it outside the airbox to not gunk it up with oil vapors.

 

[dmonkey]

I don't think there is a one-way positive crankcase ventilation (PCV) valve unless they hid it really well, but it has a long and upward path to the airbox which likely helps reduce what oil makes it there. If it's gunking up the airbox then there is likely a real issue such as having filled the crankcase with too much oil or having blow by in the engine. The engine might still benefit from lowering the pressure in the crankcase to reduce heat and such, though you would lose some engine braking by reducing that pressure. For that you could install a PCV valve, there are ones that will thread into the oil fill hole. If you really want to filter any oil out before it goes back to the airbox you could add an oil catch can to the line. If you just dump the line into the atmosphere rather than back into the airbox then it will be releasing excess hydrocarbons and unburned fuel into the atmosphere and then you not only have to deal with a bunch of Dodge Ram 1500s tailgating you on this bike, but you'll also have Captain Planet and the Planeteers following you around in a huff.

 

[Thepen]

Perfect, thanks for the advice, I think I'll go the dumping unburned fuel into the atmosphere and Dodge ram route.

 

[SneakyDingo]

I don't think there is a one-way positive crankcase ventilation (PCV) valve unless they hid it really well

RE: the PCV valve, I don't think there is one either. Once @dmonkey pointed out the location of the breather tube, I went back to the reference diagrams. After all, breathers do wear out eventually, which means they have a part number associated with them. The breather hose that attaches to the "COVER SUB-ASSY., AIR CLEANER" with clips marked 20 in this image, via the breather tube marked 1.



Since we know that this connects to the engine and roughly where it is, it seems like it'd attach at the point marked "F-25" on this diagram. There are no part numbers beyond that point, and looking at it there yields no breather valve.



Something else that I thought about when I was looking at this: This bike is a "revised and updated" model right? So what did they do for the CT110's? Well, ends up they had a complicated-but-simple breather system as well. We know that when you introduce more curves in an air intake, air is restricted somewhat. In one of the CT110 forums, they supposedly talked to a retired Honda engineer about these CT110 engines and they used a complicated airflow path to introduce enough restrictions to no longer need a breather valve.

 

[m in sc]

its just a vent tube. leave it connected to the airbox. this thing isnt turning enough rpm to cause any issues. .02

 

[Reptoid Overlords]

a bunch of Dodge Ram 1500s tailgating you on this bike

It's funny how the full sized pickups around here will not crowd you on a bike, but will tailgate the piss out of everything else. Anything built in Korea or a Lexus RX though is is being driven by someone high, late, on their phone and more important than anyone else on the road.

 

[SLO]

Perfect, thanks for the advice, I think I'll go the dumping unburned fuel into the atmosphere and Dodge ram route.

Does it run better?

 

[SLO]

Perfect, thanks for the advice, I think I'll go the dumping unburned fuel into the atmosphere and Dodge ram route.

I started smoking cigs again, so I am causing more harm than that will!

 

[m in sc]

i mean, you can run an open breather but you'll get oil mist wherever you leave it, possibly, over time. fwiw, it also pulls in any crankcase condensation that builds up. Old cars, early to mid 60s, typically ran what they called 'draft tubes' which was an open breather to the ground, no pcv. they started using pcv valves long before emissions standards were implemented.. for a good reason. this just has a captured breather tube, leave it connected. it does zero harm to anything and removing it gains nothing good. Higher rpm running, more than this motor will turn in remotely stock form, that stock tube is fine. you get into big 11k rpm bbk motors you then need to address it some, there's all sorts of fancy case breathers & catch cans in the aftermarket grom world to do whatever you wish.

 

[SLO]

i mean, you can run an open breather but you'll get oil mist wherever you leave it, possibly, over time. fwiw, it also pulls in any crankcase condensation that builds up. Old cars, early to mid 60s, typically ran what they called 'draft tubes' which was an open breather to the ground, no pcv. they started using pcv valves long before emissions standards were implemented.. for a good reason. this just has a captured breather tube, leave it connected. it does zero harm to anything and removing it gains nothing good. Higher rpm running, more than this motor will turn in remotely stock form, that stock tube is fine. you get into big 11k rpm bbk motors you then need to address it some, there's all sorts of fancy case breathers & catch cans in the aftermarket grom world to do whatever you wish.

I wasn't going to do it. I know that overfilling crankcase is BAD!

 

[SLO]

I can look at plugs and I know I am running rich. I get about 90 mpg in mountains with a 13 tooth front sprocket ,and a 3/0 17 rear tire. I have an injector for the Honda 150, a mini moto exhaust, KM type air filter. unhooked snorkel at rear rack. I have not checked valves,probably fine,3400 miles on it. I can;t see buying a fuel controller for the 143cc big bore kit. Dumb me, but why can't I put a 100 to 1 synthetic 2 cvcle oil in it , keep an I on the plugs ?if I think she's gonna run hot,or even 50 to 1 ratio? Starts to build up crud,reduce ratio.I trust mu dumb idea more than someone else''s that isn't making the part they sell, but let the lowest bid supplier,that will probably outsource various methods of acquiring products from wherever. Dumb asses invent shit! I know that you better not try and patent anything that will hurt someone else's global business or empower other people,even with a simple idea that it would take a dumb ass to think of. THINK? ???

 

[m in sc]

I have no idea why yours is running like it is over all, but i can speculate. if the filter is directly on the throttle body that's probably why though. there's a whole phenomenon of reversion on flat backed filters that completely can mess up air flow.

your mileage probably has more to do with other factors, I have the bbk, a cam, a fuel 'controller' and a 150 injector and i get over 100 still. and i know the fueling is correct because i checked it with an afr gauge.

if yours is working for you, sweet. Id recommend an all foam filter (uni) as they don't cause reversion issues. .02

 

[SLO]

Thanks! I do believe I would get a lot better mileage if I wasn't going up hills,and back and forth from about 2200 ft elevation to over 5000 ft in a few miles of distance. I was wondering what the torque specs on the valve adjustment should be on the locking nut. I was going to check today,but will have to get a set of shims to check. I will get a small torque wrench while I am at it. I am using a KM type filter I got via a link from another forum post. I have the SKA stainless I put on the shelf due to lack of filtration concerns. I did pull out the snorkel at rack,and it lays to the side. Maybe that increase of airflow could cause O2 sensor to tell ECU to give it the fuel? I am ready to put on the big bore 143cc, but If I lived Florida ,or was riding flatland in the city I probably wouldn't. Can you tell me the torque specs on that nut when you get this. Thanks again!

 

[SLO]

Oh yeah, 13 tooth front sprocket, over sized rear tire. Gonna go back to 2.75 on both when I find what I want that is in stock in that size.

 

[SLO]

I just checked valves at 3400 plus miles. Intake was at .006 adjusted to .004. Exhaust was right on at .007. That might explain plug indicating rich mixture. I put a # 6 heat range plug in it ,it came with a #7. It helped, but still was not clean after running for about 40 miles. I will see how it looks after I ride it. Was on the ground, gotta fix some kinda lift until I buy one.

 

[brian5060]

Hey all, regarding the breather system - there is a clear plastic sock connected to the air box casing. This can be seen from the exterior of the bike, no panels need to be removed (highlighted in attachment for awareness.) Am I correct in assuming this is a condensate trap? From what I see in the service manual there is no discussion or part call out for this piece. Probably because the manual states this is a “closed” system. I bring it up because mine is full of water and a bit of oil (assuming it’s oil as there is a milky white substance layered within.) Would you folks consider it good practice to purge this trap once in a while; or, not to bother? For context I have 150 miles on the bike.

 

[dmonkey]

Yes, it's a clear condensation trap on the filtered side of the airbox, and there is an open drain tube on the unfiltered side. If you observe anything in the sight tube you should clear it and it would also be a good idea to visually inspect the air filter, removing it so that you can see if oil blow-by has accumulated on the filtered side. It is a "closed" system in that it is designed to recirculate blow-by gas back to the combustion chamber rather than just vent it to the atmosphere.

If there is noticeable oil you should also check the oil level to see if it's too low or too high. Check it warm, bike on the center stand front tire touching level ground, dipstick inserted but not threaded in.

From the Owner's Manual, Page 50