concord006 Posted March 2, 2010 #1 Posted March 2, 2010 Hi all, Running a 83' Venture. I have a question about vacuum. Is there a required amount of vaccuum required? Interested in range required to run the pressure sensor for timing advance. I tested the pressure sensor and seems to be good. I am getting low fuel mileage 25mi to 32mi/us gal. Also seem like the diaphram on #2 carb is loose fitting on plunger maybe loosing vacuum. Any thoughts would be greatly apprieciated.
friesman Posted March 2, 2010 #2 Posted March 2, 2010 Welcome to the group! Glad youre here. I have the shop manuals for my 85 Venture if that would help you out, but I dont know what those vacuum specs might be. I am sure somone here will be by with the specs, but if you need to borrow the manuals for something, just send me a message, and we can see about getting them to you. Brian
Squeeze Posted March 2, 2010 #3 Posted March 2, 2010 Usually, the Vacuum is around 0.235 to 0.266 bar. The Manual says 0.266 iirc @1000 RpM. But it depends on a Lot of different Things and the RpM you running at.
concord006 Posted March 3, 2010 Author #4 Posted March 3, 2010 I now have a new problem. I just cracked my diaphram piston. It was a little loose so i figured I could tighten it a bit. Diaphram looks good but plastic piston is not. Anyone know where to get one at a reasonable price?
skydoc_17 Posted March 3, 2010 #5 Posted March 3, 2010 Hey Brent, Just a FYI here, the MKII (1986 to 1993) sliders WILL NOT fit your MKI (1983 to 1985) Carbs. I'm sure someone has a used one laying around. When you get that slider replaced, Do a Carb. Sync. on your Carb. Set and you should see an improvement in that gas mileage. Oh, be sure to check the other three Diaphragms and sliders. Welcome to the site! Earl
friesman Posted March 3, 2010 #6 Posted March 3, 2010 I now have a new problem. I just cracked my diaphram piston. It was a little loose so i figured I could tighten it a bit. Diaphram looks good but plastic piston is not. Anyone know where to get one at a reasonable price? I have a spare set of carbs that sposed to be for my 85 that I bought for the diaphragms, if you need a part off them send me a msg. I think it should fit, but not positive. Brian
Condor Posted March 3, 2010 #7 Posted March 3, 2010 Hey Brent, Just a FYI here, the MKII (1986 to 1993) sliders WILL NOT fit your MKI (1983 to 1985) Carbs. I'm sure someone has a used one laying around. When you get that slider replaced, Do a Carb. Sync. on your Carb. Set and you should see an improvement in that gas mileage. Oh, be sure to check the other three Diaphragms and sliders. Welcome to the site! Earl The only difference that I'm aware of between the MkI and MkII sliders is the bleader hole... or what ever they call it.. in the bottom part of the plastic slider. Otherwise they are one size fits all... The hole can be drilled out to match the rest. Haven't figured out how to shrink it yet.....
Squeeze Posted March 3, 2010 #8 Posted March 3, 2010 ... Haven't figured out how to shrink it yet..... Epoxy and rebore
skydoc_17 Posted March 3, 2010 #9 Posted March 3, 2010 Hey Jack, When I had GS51's 1983 VR at the shop this past summer, we had a slider do the same thing, the brass ring that held the washers that retained the Diaphragm basically fell apart. I told Gary, no problem, I have a set from a 86'VR and we would just swap them out. What we found out was the slider outside diameter on the MKII Carbs. was physically to large to go into the Carb. body of the 83'VR. P/N 83'VR Slider-41R-14949-00-00 P/N 86'VR Slider-1FK-14940-00-00 Now I am willing to admit that because GS51's (Gary) VR was the very first VR produced, that Carb. set could be one of a kind, or maybe the MKI bike you worked on has a MKII Carb. set on it, but I keep a few sets of sliders loaded with new Diaphragms for members that come to my shop to speed up the swap out process and twice, I have had the problem of not being able to put MKII sliders in a MKI bike. I will mention that especially on the 85'MKI's I have seen the MKII Carb. set on those bikes more than once so maybe they started putting the larger Carbs. on the MKI bikes before they increased the engine displacement to 1300 c.c.'s. The only reason I brought it up was I didn't want this new member to go to all the trouble to round up different sliders, (maybe even buy new ones) just to find out that they won't fit his bike. I always respect what you have to say about these bikes Jack, I was just mentioning a problem I have had with the MKI's Carbs. in the past. Earl
Condor Posted March 3, 2010 #10 Posted March 3, 2010 Hey Jack, When I had GS51's 1983 VR at the shop this past summer, we had a slider do the same thing, the brass ring that held the washers that retained the Diaphragm basically fell apart. I told Gary, no problem, I have a set from a 86'VR and we would just swap them out. What we found out was the slider outside diameter on the MKII Carbs. was physically to large to go into the Carb. body of the 83'VR. P/N 83'VR Slider-41R-14949-00-00 P/N 86'VR Slider-1FK-14940-00-00 Now I am willing to admit that because GS51's (Gary) VR was the very first VR produced, that Carb. set could be one of a kind, or maybe the MKI bike you worked on has a MKII Carb. set on it, but I keep a few sets of sliders loaded with new Diaphragms for members that come to my shop to speed up the swap out process and twice, I have had the problem of not being able to put MKII sliders in a MKI bike. I will mention that especially on the 85'MKI's I have seen the MKII Carb. set on those bikes more than once so maybe they started putting the larger Carbs. on the MKI bikes before they increased the engine displacement to 1300 c.c.'s. The only reason I brought it up was I didn't want this new member to go to all the trouble to round up different sliders, (maybe even buy new ones) just to find out that they won't fit his bike. I always respect what you have to say about these bikes Jack, I was just mentioning a problem I have had with the MKI's Carbs. in the past. Earl Yeah, interesting Earl. I've never had the problem... not to say it doesn't exist... or maybe I've just been lucky??? I've got about a 5-6 carb sets and some I've used as parts, and so far I haven't had the problem... now just watch the next time I do a mix'n'match I'll run face first into it.... But if I do I will know what's going on.... :)
GigaWhiskey Posted March 3, 2010 #14 Posted March 3, 2010 I will mention that especially on the 85'MKI's I have seen the MKII Carb. set on those bikes more than once so maybe they started putting the larger Carbs. on the MKI bikes before they increased the engine displacement to 1300 c.c.'s. The only reason I brought it up was I didn't want this new member to go to all the trouble to round up different sliders, (maybe even buy new ones) just to find out that they won't fit his bike. Earl Ok Earl, you had to just throw that out there didn't you, lol. So, how can I tell the difference visually with the diaphrams in. I would like to know what I have now.
Venturous Randy Posted March 3, 2010 #15 Posted March 3, 2010 Before you do any kind of mods on the carb/boots, make sure you do not have any vacuum leaks. An easy way to check around the carbs/boots/YICS connections is to spray either(starter fluid) in that area. The top area around the YICS box can also crack. My suggestion on the entire YICS system is to remove it all and use good plugs on the ports. RandyA
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