barend Posted January 23, 2010 Share #1 Posted January 23, 2010 (edited) In another effort to find out why she ('83 VR) is running like crap, I was looking at some of the carb sync threads and was trying to locate all applicable parts on the carbs. Instead of a "plug" on the #2 (?) cylinder (left front) I noticed there is a vacuum line on there. This used to run to a cannister above the plastic heat shield on the rear cylinders and from there to ???? The cannister had a big hole melted into it following a exhaust leak and I never traced the outgoing vac line down.I did not see "vacuum line" mentioned anywhere, so is this thing on all bikes? i.e. does it matter/is it important? Am I correct in assuming that I should be OK to cap this tube altogether? Is it safe to say that if my plugs are all a light gray and the exhaust pipes all get hot my coils are good? Same question for the CTI? (which I have not found yet!) There is (a lot of) road grime on the left front carb towards the airbox and the left rear carb appears to be "wet" as well, any idea where this may be coming from? I seem to remember some/ several saying to pull the YICS chamber, don't remember why, if I do, do I plug the hoses or cross connect them and in which way? Well that ought to get me started I think. Thanks in advance! edit: should probably add that I could smell fuel while checking around Edited January 23, 2010 by barend Link to comment Share on other sites More sharing options...
Condor Posted January 23, 2010 Share #2 Posted January 23, 2010 (edited) OK first off the '83... if it's OEM... has the vacume hose coming off a bib on the side of the #2 carb above the butterfly. The only year to do so. The hose goes to the boost sensor... yours has a hole in it. From there to the TCI it's electrical. The previous owner may have replaced the TCI with a later year and changed the vacume pick up to the #2 manafold. or.... he didn't know what he was doing. The running like cr@p could be a couple of things. The hole in the boost sensor.. main reason, .. the #2 carb bib may not be capped off, and these motors don't run worth a damn with the cover off the air cleaner box. Hope this helps a little.... Also the TCI is located underneath the plate in front of the batery box and behind the boost sensor. A ***** to get to. Most folks relocate it to the top of the air cleaner box when replacing. On the grime. Get a couple of cans of carb cleaner and spray the 'H' out of the carbs. Afterwords take some 'Deep Creap'... made by Sea Foam... and lube all the linkage and choke pistons, and anything else that moves. Carbs will get dirty over time and yours may never have been cleaned since they were installed at the factory?? Edited January 23, 2010 by Condor Link to comment Share on other sites More sharing options...
dingy Posted January 23, 2010 Share #3 Posted January 23, 2010 (edited) I did not see "vacuum line" mentioned anywhere, so is this thing on all bikes? i.e. does it matter/is it important? Am I correct in assuming that I should be OK to cap this tube altogether? Is it safe to say that if my plugs are all a light gray and the exhaust pipes all get hot my coils are good? Same question for the CTI? (which I have not found yet!) Do yo mean CDI? If bike is firing okay what is concern about the CDI. CDI is located under coil mount bracket. There is (a lot of) road grime on the left front carb towards the airbox and the left rear carb appears to be "wet" as well, any idea where this may be coming from? See this thread for info on oil on left carbs. This comes from accumulated oil in air box draining out left side and down onto carbs when bike is on side stand. Attached is Tech Notice from Yamaha on fixing oil... I seem to remember some/ several saying to pull the YICS chamber, don't remember why, if I do, do I plug the hoses or cross connect them and in which way? One of several threads on YICS chamber. http://www.venturerider.org/forum/showthread.php?t=35356 Well that ought to get me started I think. Thanks in advance! edit: should probably add that I could smell fuel while checking around Gary Edited January 23, 2010 by dingy Link to comment Share on other sites More sharing options...
barend Posted January 23, 2010 Author Share #4 Posted January 23, 2010 OK first off the '83... if it's OEM... has the vacume hose coming off a bib on the side of the #2 carb above the butterfly. The only year to do so. The hose goes to the boost sensor... yours has a hole in it. http://www.venturerider.org/forum/album.php?albumid=445&pictureid=2643 is that little box on the top the boost sensor? It has two vacuum ports and no electrical. The hose coming from the carb is attached to a bib just to the left and slightly below the throttle stop screw From there to the TCI it's electrical. The previous owner may have replaced the TCI with a later year and changed the vacume pick up to the #2 manafold. or.... he didn't know what he was doing. The running like cr@p could be a couple of things. The hole in the boost sensor.. main reason, .. the #2 carb bib may not be capped off, and these motors don't run worth a damn with the cover off the air cleaner box. Hope this helps a little.... Also the TCI is located underneath the plate in front of the batery box Ahh!! and behind the boost sensor. :confused07: you got me! you say the boost sensor is essentially in front and below the battery box, you're also saying my boost sensor is shot (from heat generated by the rear cylinder exhaust??) A ***** to get to. Most folks relocate it to the top of the air cleaner box when replacing. On the grime. Get a couple of cans of carb cleaner and spray the 'H' out of the carbs. Afterwords take some 'Deep Creap'... made by Sea Foam... and lube all the linkage and choke pistons, and anything else that moves. Carbs will get dirty over time and yours may never have been cleaned since they were installed at the factory?? Probabaly not:D So I guess the next question would be: can I cap this #2 bib? i.e do I need the boost sensor? I may see if I can get ahold of you on the phone after work, if that's OK? Thanks for the links Gary! Link to comment Share on other sites More sharing options...
dingy Posted January 23, 2010 Share #5 Posted January 23, 2010 (edited) I believe I have a spare boost sensor I can get you. Shipping cost only. Sensor is off of an 88, but the parts fiche shows the same part # for the 83 & 88 so it should be OK. On my 83 all 4 bibs on intake manifolds are capped. What would be helpful is to know model # of your CDI. Just in case a previous owner changed it out. The 83 ran from a port just above throttle plates. 84 and later ran from intake boot port. Attached is a picture of my 83 carb rack, throttle cable side, showing black rubber hose that goes to boost sensor. Gary Edited January 23, 2010 by dingy Link to comment Share on other sites More sharing options...
Condor Posted January 23, 2010 Share #6 Posted January 23, 2010 I re read your first post. I don't know what that canister is, but I take a guess and say it's the canister for the California smog. My '83 has it in front over the heat shield. I'd disconect it. Sorry about my being not reading right. Your boost is propably OK. I'd just cap off all the vacume ports on the manafolds and run a vacume hose from the #2 carb bib to the boost sensor. The boost sensor is located in front of the TCI.... Link to comment Share on other sites More sharing options...
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