Chaplain Dusty Posted January 25, 2015 #1 Posted January 25, 2015 Considering the carb problems on the 83' Venture, would it be worth going to say 85' carbs?
Venturous Randy Posted January 25, 2015 #2 Posted January 25, 2015 The carbs will work, but you will need to have an 84 to 89(I think) TCI and run the boost sensor vacuum hose to a port off the manifold. Randy
jasonm. Posted January 25, 2015 #3 Posted January 25, 2015 the carbs are for the same exact engine. Yes they will work. Boost sensor?...that won't be an issue...you are just changing the carbs. The sensor hooks to the manifold.
Prairiehammer Posted January 25, 2015 #4 Posted January 25, 2015 the carbs are for the same exact engine. Yes they will work. Boost sensor?...that won't be an issue...you are just changing the carbs. The sensor hooks to the manifold. That is incorrect. The 1983 carb is unique in that the vacuum advance (Boost Sensor) is hooked to a spigot on the carb body NOT to the intake boot as on the later years. So as Randy stated, if you used 1984 and later carbs on the 1983, the TCI must be changed as well. Perhaps one could drill into the carb body of a later carb (there is a blank boss where on the 1983 the vacuum pickup is installed) and add the spigot for the Boost Sensor and retain the 1983 TCI. The 1983 TCI is unique to that year, too.
Chaplain Dusty Posted February 16, 2015 Author #5 Posted February 16, 2015 Thanks for the feedback. I've been having issues on hard starting. I had the 83' carbs cleaned up and re-jetted for the high altitude of Northern New Mexico and the carbs have been sinked, but I continue to have issues. This is why I was considering different carbs. Just want the bike to be reliable in that respect. Chaplain Dusty
Prairiehammer Posted February 16, 2015 #6 Posted February 16, 2015 (edited) Thanks for the feedback. I've been having issues on hard starting. I had the 83' carbs cleaned up and re-jetted for the high altitude of Northern New Mexico and the carbs have been sinked, but I continue to have issues. This is why I was considering different carbs. Just want the bike to be reliable in that respect. Chaplain Dusty Ken, what are the issues with your current carbs? "Hard starting"? Meaning the engine turns over, but it is reluctant to fire? Is this issue occurring with a cold engine or when the engine is warmed up? How does the bike perform after getting it started? What is your fuel mileage? Have you replaced the spark plugs? How many miles on the bike? Has the engine compression been checked? Have you checked the valve clearances? What is the idling rpm of the warm engine? As you may now realize, hard starting can be caused by many things, not just the carbs. The 1983 carbs are not inherently more troublesome when compared to other years. Finally, because all Constant Velocity carburetors (the Venture carbs are CV carbs) are intrinsically altitude compensating, rejetting to compensate for the high altitude is a finicky endeavor, where the science of such is mostly misunderstood and usually becomes a trial and error experience. Unless you were to miraculously find a set of brand new carbs, it is likely that you will still have issues with any used carbs that you find. Unless the carbs you have are actually "worn out" (an oft used but incorrect phrase, since unless there is excessive wear at the throttle plate shaft, the carbs are not "worn" out). All the Venture carbs share major and minor components with each other and with the First Generation V-Max. Thus, parts to refresh and make the carbs like new are available. The one fly in this ointment is the mechanic's skill and attention to detail. Here on this forum we regularly encounter users who have had their Venture carbs "rebuilt" and yet continue to have problems. Most problems after the ersatz rebuild are a result of incorrect and or incomplete "refurbishment" and or poor quality parts. Elaborate your particular issues here and we will help you to restore efficient and reliable operation to your carbs and to the Venture. Edited February 16, 2015 by Prairiehammer
Marcarl Posted February 16, 2015 #7 Posted February 16, 2015 Yep,,, I agree,,,for me the question is: what exactly is meant by cleaned,, like exactly,,,, were the carbs stripped right down? every screw and gasket removed? every hole cleaned and cleaned again? and then checked to make sure they were clean and open, were the floats set and rechecked? and checked for leaks?,,,, or,,,,,,,was a carb cleaner sprayed around for a bit to make things look clean and pretty and then put money in the pocket. Yep! sure is a difference.
videoarizona Posted February 16, 2015 #8 Posted February 16, 2015 Ken, I agree with Kevin as well. Altitude adjustments mean nothing to a CV carb. My Austin Healey with SU carbs went from sea level to Mile High Denver and all I had to do was change the mechanical timing (The VR's have a computer). In extreme cold days of winter, I opened the enrichment port 3 turns for a slightly richer mixture. This "port" was nothing more than an adjustable seat for the CV slide...with very fine threads. We don't need it with our CV. But if you did find your bike running really lean, then changing one jet would be the choice I would make. But in reality, I doubt you will need that. If the diaphrams are good, if the fuel delivery is good, if the spark is good, if the TCI (computer) is good, if the electrical connections throughout the running and ignition circuits are clean, if the plugs and wires are good, if the coils are good...she will start and run like a dream. It's simply a matter of taking one step at a time, one system at a time and going through it. No shotgun approaches here allowed. I look at it this way....I've had my bike for almost one year now. I'm slowly going through each system as I learn about them here on the forum. Making changes or simply cleaning everything I can get into. I figure by doing this, I'm making the bike more reliable AND learning how to work on the bike at the same time. Riding and working on the bike were the two reasons I bought a VR. So far so good! I'm hoping you have the same fun and success I've been having (despite some frustrations on my part for sure)!! So I would recommend taking the carbs off and going through them on your own. Learn them. Have fun rebuilding them to the extant that you are comfortable with. Lots of info and help here... Then move on to the next thing on your list! david
Chaplain Dusty Posted February 18, 2015 Author #9 Posted February 18, 2015 Ken, what are the issues with your current carbs? "Hard starting"? Meaning the engine turns over, but it is reluctant to fire? Is this issue occurring with a cold engine or when the engine is warmed up? How does the bike perform after getting it started? What is your fuel mileage? Have you replaced the spark plugs? How many miles on the bike? Has the engine compression been checked? Have you checked the valve clearances? What is the idling rpm of the warm engine? As you may now realize, hard starting can be caused by many things, not just the carbs. The 1983 carbs are not inherently more troublesome when compared to other years. Finally, because all Constant Velocity carburetors (the Venture carbs are CV carbs) are intrinsically altitude compensating, rejetting to compensate for the high altitude is a finicky endeavor, where the science of such is mostly misunderstood and usually becomes a trial and error experience. Unless you were to miraculously find a set of brand new carbs, it is likely that you will still have issues with any used carbs that you find. Unless the carbs you have are actually "worn out" (an oft used but incorrect phrase, since unless there is excessive wear at the throttle plate shaft, the carbs are not "worn" out). All the Venture carbs share major and minor components with each other and with the First Generation V-Max. Thus, parts to refresh and make the carbs like new are available. The one fly in this ointment is the mechanic's skill and attention to detail. Here on this forum we regularly encounter users who have had their Venture carbs "rebuilt" and yet continue to have problems. Most problems after the ersatz rebuild are a result of incorrect and or incomplete "refurbishment" and or poor quality parts. Elaborate your particular issues here and we will help you to restore efficient and reliable operation to your carbs and to the Venture. When I first got the bike, it would not start. I replaced the battery and it turned over, but to no avail. I took it to the Yamaha dealer to have the carbs cleaned, etc., which was done, but found that the TCI unit was bad. That has been replaced. Of course none of this was cheap. The bike ran very well for about a week with the exception of some backfiring, but was still hard starting when cold. It then began idling rough and at times would quit running. I took it back to Yamaha and asked them if they had synchronized the carbs after their rebuild (not sure exactly what was done other than cleaning). They said that they had and didn't understand why their adjustments had not held. At any rate, they synchronized the carbs and all seemed great and the bike seemed to start a little bit easier, but still took awhile to start when cold. When the bike is warm, she normally starts pretty regularly and runs well. Now, she acts as if she will start, but to no avail. I have found that it is best not to use the choke. She floods real easy. The fuel mileage does not seem too great when she is running. The compression was checked and was ok. I have not ridden for over 20 years, so a lot of what I used to know has gone by the wayside with age, but I need to figure this out.
bongobobny Posted February 18, 2015 #10 Posted February 18, 2015 Hmmm, a pinhole or two on the diaphragms comes to mind. You might try a can of seafoam in the gas and ride it like you stole it, but that will only help to clean the carbs out but won't fix bad diaphragms...
Neil86 Posted February 18, 2015 #11 Posted February 18, 2015 (edited) A couple suggestions.... The 83-85 have a YICS system, meaning hoses running from intake ports on head to a plastic reservoir. The reservoir (YICS chamber) is prone to leaks as the plastic ages and can result in vacuum leaks which might explain the poor cold starting you are encountering. Many YICS systems have been abandoned and the ports capped off. As mentioned earlier the 1983 used a vacuum signal from the #2 (Left front carb) and a unique TCI. If they replaced the TCI with an 84-89 model the vacuum signal has to come from a synch port NOT the carb, or else your timing advance will be way off and performance will suffer. If the TCI has a 41R- xx number on the foil sticker its a 84-89 model...if its a 26H-xx is the 83 model TCI. Edited February 18, 2015 by Neil86
cowpuc Posted February 20, 2015 #12 Posted February 20, 2015 IMHO, lots of GREAT advice happening here Chap! What your describing sounds familiar to a situation I was having with Tweeks last spring. After testing and diagnosing, I finally came to the conclusion that her low fuel economy and hard starting was being caused by a very tired motor not being able to handle the fuel she was getting.. I am an old 2 stroke Motocross guy and have done TONS of two stroke tuning (plug chops, plug chops and MORE plug chops) and have done my share of fattening em up and leaning em down via the slide needle that controls fuel flow within the main jet after having proper jetting.. Anyway, what I was seeing on Tweeks plugs and feeling in her performance reminded a LOT of those days. I went looking for a way to fine tune the needles in her slides (basically doing to a CV carb what we are not suppose to do). What I discovered on Tweeks was that, due to wear and tear, I needed to lean her down considerably on the needles.. I figured I would give it shot.. Of course, those CV carbs have "fixed" needles in their slides. If you pull the diaphram and slides (check em real close for pin holes and tears), take the slides apart, drop the needles and you will see a small,,, hey,, wait a minute here, I think I posted this on here already,, let me see if I can find that old post..
Chaplain Dusty Posted February 22, 2015 Author #13 Posted February 22, 2015 Cowpuc, Thanks for the great info. I'm changing the oil on "Francis" and replacing the front wheel bearings. I will then begin on the carb issues. I've got spring break coming up and will have about two weeks of time to jump on those puppies. I'm looking forward to getting in some good riding in the near future. Bless you my brother!
Chaplain Dusty Posted February 22, 2015 Author #14 Posted February 22, 2015 Neil, Thanks for the info. This is a learning experience and I need a biggggggg learning curve. I will check that out. When I took it to Yamaha about the rough idle, etc. after they did the carb work, they had mentioned that it could possible be a vacuum leak in the hoses, which they checked out. Whether they looked at the YICS system or not, I do not know. After they synched the carbs, it ran real well for about two weeks and was easier to start, Yet now, she will not start. Chaplain Dusty
cowpuc Posted February 23, 2015 #15 Posted February 23, 2015 @Chaplain Dusty, here is a link to that thread I was looking for. http://www.venturerider.org/forum/watering-hole/86325-carb-metering-rod-question.html?highlight=slide+needle I couldnt remember if I had actually sent this to you or not. I did end up dropping the needles on Tweeks by 67 thou as I recall. I worked perfect, she got and held her MPG just fine and maintained the ability to still run 85 octane (no spark knock from running to lean). She also made the whole summer last year and didnt burn down so I guess the jetting is pretty close. I didnt dare go any farther than the 67 thou though cause I had a hunch I would have to rejet my pilots and I didnt want to put that kind of work in her, again. Hope this helps and BLESS YOU TOO my brother!! Puc
Cuthbert42 Posted February 25, 2015 #16 Posted February 25, 2015 One question that comes to mind is, have you checked the valve clearances. It doesn't matter how clean you carbs are if your valves are out of spec. When that is done, clean the carbs yourself, most shops have no interest in properly cleaning 30 year old carbs, you'll also learn a lot more about your bike if you do the work yourself. Just my two cents.
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