cowtownchemist Posted March 12 Share Posted March 12 I replaced my breather hose over the weekend. Getting the old one out was pretty easy with the tank off. Getting the new one in was a struggle. There is just not much room to get your hands in there and get the right leverage to force the hose onto the openings. But after a few choice words and a little determination I got it on securely. One thing I learned is that the MG Cycle breather hose clamp is too small for the upper attachment to the frame. It worked for the lower side to the engine but I had to use the original clamp for the upper end. https://www.mgcycle.com/index.php?main_page=product_info&cPath=71&products_id=1186 https://www.mgcycle.com/index.php?main_page=product_info&cPath=71&products_id=2785 Old vs. New 3 3 Link to comment Share on other sites More sharing options...
guzzler Posted March 12 Share Posted March 12 Exactly where mine went too! Cheers 1 Link to comment Share on other sites More sharing options...
audiomick Posted March 12 Share Posted March 12 3 hours ago, guzzler said: Exactly where mine went too! I dare say they all give up more or less there. The motor is "rigidly" mounted to the frame, so the motor movement (vibration) relative to the frame is probaly fairly minimal. The hose, however, has two long straight sections with a bend in the middle, and no support along the way. The vibrations caused by the motor have a significant sideways component, so the hose is going to be moving like the belly on a fat cat when it gets a trot up on the way to dinner. The hose no doubt vibrates along its length quite a lot, and that no doubt puts stress on the bends at the ends and the anchor points. Incidently, there are a lot of really good excuses for having a paunch in there... 2 Link to comment Share on other sites More sharing options...
docc Posted March 12 Share Posted March 12 I also wonder about the motor oil in use affecting the longevity. "Mineral" oils have a significant heat-driven evaporative component while true synthetics (Group IV and Group V base oils) do not. I did change my hose while fighting various oil leaks, I saved my take-off as it was not faulty. That was at about 100,000 miles/ 161,000 km. 3 Link to comment Share on other sites More sharing options...
audiomick Posted March 12 Share Posted March 12 @docc aren't we supposed to only use synthetic oils in our V11s? Either way, I don't doubt what you wrote in the least, but rubber parts just get old. If your old hose was still good (pun intended...), I reckon there was a bit of luck involved as well. Link to comment Share on other sites More sharing options...
docc Posted March 13 Share Posted March 13 16 minutes ago, audiomick said: @docc aren't we supposed to only use synthetic oils in our V11s? Either way, I don't doubt what you wrote in the least, but rubber parts just get old. If your old hose was still good (pun intended...), I reckon there was a bit of luck involved as well. In spite of carrying various talisman on my person, and on mySport, at all times, I am not much of a believer in luck. VooDoo, sure, but not "luck" . . . "Synthetic" oil runs the gambit of claims and allowances. Good luck finding out what the actual base oil is on your motor oil of choice. There are but a very few actual Group IV/ Group V base oils. That true, full synthetic motor oils do not suffer the heat-evaporative losses of other oils might suggest a lesser load on our crankcase ventilation and less stress on this failure-prone hose. Of course, very humid environs, storage conditions, and even tuning status (too much fuel load?) all contribute to what this crankcase ventilation hose has to suffer from . . . 2 Link to comment Share on other sites More sharing options...
docc Posted March 13 Share Posted March 13 Also, be aware this vent hose can be abraded by contact with motor parts . . . 1 1 Link to comment Share on other sites More sharing options...
cowtownchemist Posted March 13 Share Posted March 13 The failure of this hose caused a lot of muck and grime to leak out and get all over everything under my tank. It was so bad that I couldn't even see the red of the frame. Everything looked black. My question is, when the hose is functioning properly, where does all the oil go? Is it just getting spit into the frame? Sorry if this is a dumb question... Link to comment Share on other sites More sharing options...
LaGrasta Posted March 13 Share Posted March 13 2 hours ago, cowtownchemist said: The failure of this hose caused a lot of muck and grime to leak out and get all over everything under my tank. It was so bad that I couldn't even see the red of the frame. Everything looked black. My question is, when the hose is functioning properly, where does all the oil go? Is it just getting spit into the frame? Sorry if this is a dumb question... This hose is a only a breather, allowing heat and gases to escape, actual liquid oil is meant to run back down into the crankcase. Link to comment Share on other sites More sharing options...
docc Posted March 13 Share Posted March 13 To take that a step further, the box section spine frame serves as a separator with the liquid fraction draining through the spine into the braided line that rejoins the oil sump at the back while the vapor fraction enters the airbox to be combusted. Or just gunk up the airbox . . . 5 1 Link to comment Share on other sites More sharing options...
GuzziMoto Posted March 13 Share Posted March 13 What docc said. The vent goes into the frame at the top. What is vented is a mixture of air pressure (from pistons moving up and down changing the volume of the area in the crankcases, plus some blow by past the piston rings) and oil that is carried in the moving air. That oil is something of a fine mist, typically. Once in the frame at the top the air slows down and the mist of oil collects and drains down to the bottom of that section of the spine frame. There you will find drain lines that route the collected oil back into the sump at the bottom. Some spine frames have 1 drain line, others have a pair. I have no idea why they would use two lines back to the sump, one should do. Meanwhile that air pressure that carried the oil into the spine frame is then vented into the airbox. Ideally it is just air at that point, no oil. But if you overfill your sump with oil you can end up with excess oil being blown into the airbox as it can overwhelm the system that is trying to remove the oil from the air that it vents. 4 1 Link to comment Share on other sites More sharing options...
cowtownchemist Posted March 13 Share Posted March 13 Thanks all for the replies. Today I learned something! 1 Link to comment Share on other sites More sharing options...
LaGrasta Posted March 13 Share Posted March 13 I work in advertising, being concise is an art that none of you have obviously mastered. 1 Link to comment Share on other sites More sharing options...
PJPR01 Posted March 13 Share Posted March 13 15 minutes ago, LaGrasta said: I work in advertising, being concise is an art that none of you have obviously mastered. Ahem...do you always take the short route home on the motorbike or sometimes the leisurely, meandering longer route? Which one is more enjoyable? 1 3 Link to comment Share on other sites More sharing options...
Lucky Phil Posted March 16 Share Posted March 16 On 3/14/2024 at 9:18 AM, LaGrasta said: I work in advertising, being concise is an art that none of you have obviously mastered. I've heard many opinions on advertising over the years but "concise" has never been one of them. Phil 1 2 Link to comment Share on other sites More sharing options...
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