DeeGee Posted July 28, 2014 Share #1 Posted July 28, 2014 The crankcase ventilation tube that comes out the left side of the engine and goes up the frame. Where does this connect to? Or does it not connect to anything? Link to comment Share on other sites More sharing options...
Neil86 Posted July 28, 2014 Share #2 Posted July 28, 2014 On a 1st gen (83-93) Venture the crankcase vent hose is connected to bottom of airbox other end is connected to middle of the oblong breather chamber directly below carbs at base of cylinders. Link to comment Share on other sites More sharing options...
Peder_y2k Posted July 28, 2014 Share #3 Posted July 28, 2014 (edited) I rerouted the big hose from twinkie to airbox (using a new hose) to dump under the bike frame. This to keep oil vapor out of the airbox........when the vapor condenses, it forms a puddle that leaks out of the airbox and drips on the motor. I prefer it drip on the ground......but the hose doesn't drip. -Pete, in Tacoma WA USA Edited July 28, 2014 by Peder_y2k Link to comment Share on other sites More sharing options...
KIC Posted July 28, 2014 Share #4 Posted July 28, 2014 some people ,like me have a "T" installed half way up the tube to help stop the sucking of the oil into the airbox. My T goes up along the left side. Since the airbox really is sensitive to extra air (leaks) I put a small bolt in the end to keep the air leak from being big. if your hose is not connected to the bottom of the air box, make sure it is blocked off. Also, in order to work on those hoses, go to harbor freight and get the set of long needle nose plyers. they are worth their weight in gold when working on the Venture. Link to comment Share on other sites More sharing options...
DeeGee Posted July 28, 2014 Author Share #5 Posted July 28, 2014 some people ,like me have a "T" installed half way up the tube to help stop the sucking of the oil into the airbox. My T goes up along the left side. Since the airbox really is sensitive to extra air (leaks) I put a small bolt in the end to keep the air leak from being big. if your hose is not connected to the bottom of the air box, make sure it is blocked off. Also, in order to work on those hoses, go to harbor freight and get the set of long needle nose plyers. they are worth their weight in gold when working on the Venture. That's how mine is. It's still hooked up to the air box. But then Ts off and comes out the left side. When i noticed the tube it was connected to anything. I wasn't sure if I pulled it off trying to install my new plug wires. Link to comment Share on other sites More sharing options...
yamagrl Posted July 28, 2014 Share #6 Posted July 28, 2014 Most of you "Gearheads" and "Wrenchers" recognize the importance and value of a properly functioning PCV system and when giving a car a tune-up would always replace the PCV valve and never disable the PCV system. I rearched this same dilemma on our Vstar. I elect to deal with the oil in the air box. This is normal and apparently causes no real problems. Just a small amount of oil in the airbox. The biggest problem is getting the hose connected to the airbox. Link to comment Share on other sites More sharing options...
yamagrl Posted July 28, 2014 Share #7 Posted July 28, 2014 Researched Link to comment Share on other sites More sharing options...
Prairiehammer Posted July 28, 2014 Share #8 Posted July 28, 2014 On an unmolested First Gen, there are TWO hoses connected to the airbox; a larger hose that is connected to the 'twinky' at the bottom and to the rear of the airbox at the top and a smaller hose that connects to a small nipple at left front corner of the airbox and to a T-fitting in the large hose just above the twinky. The large hose is the crankcase ventilation (think PCV, Positive Crankcase Ventilation on your car). The smaller hose is the drain back hose for accumulated oil in the airbox. On the early Ventures, this small hose did not connect to the larger hose and there was no T in the larger hose. On those early Ventures the airbox drain was to the ground through a check valve. Yamaha issued a TSB to eliminate the airbox draining to the ground and route the airbox accumulated oil to a new T in the crankcase ventilation hose. Link to comment Share on other sites More sharing options...
yamagrl Posted July 28, 2014 Share #9 Posted July 28, 2014 Mine has both Link to comment Share on other sites More sharing options...
DeeGee Posted July 28, 2014 Author Share #10 Posted July 28, 2014 so the hose coming off the T is just a drain? It doesn't connect to anything? Link to comment Share on other sites More sharing options...
yamagrl Posted July 28, 2014 Share #11 Posted July 28, 2014 It connects back up to the front of the airbox Link to comment Share on other sites More sharing options...
DeeGee Posted July 28, 2014 Author Share #12 Posted July 28, 2014 It connects back up to the front of the airbox Awesome thank you! My air box isn't in the bike right now. Probably the reason why i dont see where it hooks up lol Link to comment Share on other sites More sharing options...
KIC Posted July 28, 2014 Share #13 Posted July 28, 2014 So if you have the "T" coming off the hose and the small hose nipple on the airbox is closed off, should the "T" hose be totally closed off ? Mine came with a second small cone shape filter on the "T" hose that was leaving oil everywhere. I took the cone filter off and just put a bolt in it that wasn't "tight" so that a little air would allow the oil to flow back down and not get sucked into the airbox. Link to comment Share on other sites More sharing options...
Neil86 Posted July 28, 2014 Share #14 Posted July 28, 2014 KIC.. If you are venting the crankcase to atmosphere, yes cap the air box nipples. With the setup you found on your bike....it would have been venting crankcase out the cone filter too, causing the mess. Might as well remove the small hose into tee and cap it there so everything blows out the large hose wherever you point it. The drain hose is to drain accumulated oil from the airbox, so you are no longer needing it. Kevin... I think the object in the original 83-84? drain hose was an inline filter to prevent dirty air migrating back into airbox. The RSV has one on both drain hoses from the air plenums. Link to comment Share on other sites More sharing options...
Prairiehammer Posted July 28, 2014 Share #15 Posted July 28, 2014 Kevin...I think the object in the original 83-84? drain hose was an inline filter to prevent dirty air migrating back into airbox. The RSV has one on both drain hoses from the air plenums. Yes, of course, you are correct, Neil. I had a mental lapse, and was mixing up the check valve in the vacuum line from number two carb to the boost sensor with the filter in the '83-'84 airbox drain line. Rather curious that the filter that is on the '83 drain line is identical to the filter on the RSV. The oil drain hose does not make a mess on the RSV? I think the oily discharge was the reason the airbox drain was changed on the First Gen, starting with 1985. Then Yamaha reverted to the same drain and filter for the 1999? Link to comment Share on other sites More sharing options...
Neil86 Posted July 28, 2014 Share #16 Posted July 28, 2014 well perhaps its not identical...but same concept...however the RSV drains the plenums down behind the engine where the coolant and tank vent hoses are...didn't the 83 drain upwind of the engine so it could blow back onto frame. Link to comment Share on other sites More sharing options...
Prairiehammer Posted July 28, 2014 Share #17 Posted July 28, 2014 well perhaps its not identical...but same concept...however the RSV drains the plenums down behind the engine where the coolant and tank vent hoses are...didn't the 83 drain upwind of the engine so it could blow back onto frame. The filter is identical, same part number. http://www.boats.net/parts/detail/yamaha/Y-4X7-2149Y-00-00.html And yes, the outlet of the airbox drain on the '83 is just in front of the engine, left of the oil filter. Link to comment Share on other sites More sharing options...
Neil86 Posted July 28, 2014 Share #18 Posted July 28, 2014 wonder if anyone has ever replaced one...lol Regarding the open vent...I know my 86 sorta reeks if the hose isn't attached securely to airbox. Link to comment Share on other sites More sharing options...
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